CImage.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#include "img-precomp.h"  // Precompiled headers

#include <mrpt/img/CImage.h>
#include <mrpt/io/CFileInputStream.h>
#include <mrpt/io/CFileOutputStream.h>
#include <mrpt/io/CMemoryStream.h>
#include <mrpt/io/zip.h>
#include <mrpt/math/CMatrix.h>
#include <mrpt/math/fourier.h>
#include <mrpt/math/utils.h>  // for roundup()
#include <mrpt/core/round.h>  // for round()
#include <mrpt/system/CTicTac.h>
#include <mrpt/system/CTimeLogger.h>
#include <mrpt/system/memory.h>
#include <mrpt/system/filesystem.h>
#include <mrpt/serialization/CArchive.h>
#include <iostream>

// Universal include for all versions of OpenCV
#include <mrpt/otherlibs/do_opencv_includes.h>

#if MRPT_HAS_MATLAB
#include <mexplus/mxarray.h>
#endif

// Prototypes of SSE2/SSE3/SSSE3 optimized functions:
#include "CImage_SSEx.h"

using namespace mrpt;
using namespace mrpt::img;
using namespace mrpt::math;
using namespace mrpt::system;
using namespace std;

// This must be added to any CSerializable class implementation file.
IMPLEMENTS_SERIALIZABLE(CImage, CSerializable, mrpt::img)

bool CImage::DISABLE_ZIP_COMPRESSION = false;
bool CImage::DISABLE_JPEG_COMPRESSION = false;
int CImage::SERIALIZATION_JPEG_QUALITY = 95;

static std::string IMAGES_PATH_BASE(".");

const std::string& CImage::getImagesPathBase() { return IMAGES_PATH_BASE; }
void CImage::setImagesPathBase(const std::string& path)
{
    IMAGES_PATH_BASE = path;
}

// Do performance time logging?
#define IMAGE_ALLOC_PERFLOG 0

#if IMAGE_ALLOC_PERFLOG
mrpt::img::CTimeLogger alloc_tims;
#endif

/*---------------------------------------------------------------
                    Constructor
---------------------------------------------------------------*/
CImage::CImage(
    unsigned int width, unsigned int height, TImageChannels nChannels,
    bool originTopLeft)
    : img(nullptr), m_imgIsReadOnly(false), m_imgIsExternalStorage(false)
{
    MRPT_START
    changeSize(width, height, nChannels, originTopLeft);
    MRPT_END
}
/*---------------------------------------------------------------
            Default Constructor
---------------------------------------------------------------*/
CImage::CImage()
    : img(nullptr), m_imgIsReadOnly(false), m_imgIsExternalStorage(false)
{
#if MRPT_HAS_OPENCV
    MRPT_START
    changeSize(1, 1, CH_RGB, true);
    MRPT_END
#endif
}

/*---------------------------------------------------------------
                    Copy constructor
---------------------------------------------------------------*/
CImage::CImage(const CImage& o)
    : img(nullptr), m_imgIsReadOnly(false), m_imgIsExternalStorage(false)
{
    MRPT_START
    *this = o;
    MRPT_END
}

/*---------------------------------------------------------------
                    Copy operator
---------------------------------------------------------------*/
CImage& CImage::operator=(const CImage& o)
{
    MRPT_START
    if (this == &o) return *this;
    releaseIpl();
    m_imgIsExternalStorage = o.m_imgIsExternalStorage;
    m_imgIsReadOnly = false;

    if (!o.m_imgIsExternalStorage)
    {  // A normal image
#if MRPT_HAS_OPENCV
        ASSERTMSG_(
            o.img != nullptr,
            "Source image in = operator has nullptr IplImage*");
        img = cvCloneImage((IplImage*)o.img);
#endif
    }
    else
    {  // An externally stored image:
        m_externalFile = o.m_externalFile;
    }
    return *this;
    MRPT_END
}

/*---------------------------------------------------------------
                swap
---------------------------------------------------------------*/
void CImage::swap(CImage& o)
{
    std::swap(img, o.img);
    std::swap(m_imgIsReadOnly, o.m_imgIsReadOnly);
    std::swap(m_imgIsExternalStorage, o.m_imgIsExternalStorage);
    std::swap(m_externalFile, o.m_externalFile);
}

/*---------------------------------------------------------------
                copyFromForceLoad

Copies from another image, and, if that one is externally
stored, the image file will be actually loaded into memory
in "this" object.
---------------------------------------------------------------*/
void CImage::copyFromForceLoad(const CImage& o)
{
    if (o.isExternallyStored())
    {
        // Load from that file:
        if (!this->loadFromFile(o.getExternalStorageFileAbsolutePath()))
            THROW_TYPED_EXCEPTION_FMT(
                mrpt::img::CExceptionExternalImageNotFound,
                "Error loading externally-stored image from: %s",
                o.getExternalStorageFileAbsolutePath().c_str());
    }
    else
    {  // It's not external storage.
        *this = o;
    }
}

/*---------------------------------------------------------------
                copyFastFrom
---------------------------------------------------------------*/
void CImage::copyFastFrom(CImage& o)
{
    MRPT_START
    if (this == &o) return;
    if (o.m_imgIsExternalStorage)
    {
        // Just copy the reference to the ext. file:
        *this = o;
    }
    else
    {  // Normal copy
#if MRPT_HAS_OPENCV
        if (!o.img) THROW_EXCEPTION("Origin image is empty! (o.img==nullptr)");
#endif
        // Erase current image:
        releaseIpl();

        // Make the transfer of just the pointer:
        img = o.img;
        m_imgIsReadOnly = o.m_imgIsReadOnly;
        m_imgIsExternalStorage = o.m_imgIsExternalStorage;
        m_externalFile = o.m_externalFile;

        o.img = nullptr;
        o.m_imgIsReadOnly = false;
        o.m_imgIsExternalStorage = false;
    }

    MRPT_END
}

/*---------------------------------------------------------------
                    Constructor from IplImage
---------------------------------------------------------------*/
CImage::CImage(void* iplImage)
    : img(nullptr), m_imgIsReadOnly(false), m_imgIsExternalStorage(false)
{
    MRPT_START

#if MRPT_HAS_OPENCV
    if (!iplImage)
        changeSize(1, 1, 1, true);
    else
        img = cvCloneImage((IplImage*)iplImage);
#endif
    MRPT_END
}

/*---------------------------------------------------------------
                    Destructor
---------------------------------------------------------------*/
CImage::~CImage() { releaseIpl(); }
/*---------------------------------------------------------------
                    changeSize
---------------------------------------------------------------*/
void CImage::changeSize(
    unsigned int width, unsigned int height, TImageChannels nChannels,
    bool originTopLeft)
{
    MRPT_START

#if MRPT_HAS_OPENCV
    // If we're resizing to exactly the current size, do nothing and avoid
    // wasting mem allocs/deallocs!
    if (img)
    {
        makeSureImageIsLoaded();  // For delayed loaded images stored externally
        IplImage* ipl = static_cast<IplImage*>(img);
        if (static_cast<unsigned int>(ipl->width) == width &&
            static_cast<unsigned int>(ipl->height) == height &&
            ipl->nChannels == nChannels &&
            ipl->origin == (originTopLeft ? 0 : 1))
        {
            return;  // nothing to do, we're already right with the current
            // IplImage!
        }
    }

    // Delete current img
    releaseIpl();

#if IMAGE_ALLOC_PERFLOG
    const std::string sLog = mrpt::format("cvCreateImage %ux%u", width, height);
    alloc_tims.enter(sLog.c_str());
#endif

    img = cvCreateImage(cvSize(width, height), IPL_DEPTH_8U, nChannels);
    ((IplImage*)img)->origin = originTopLeft ? 0 : 1;

#if IMAGE_ALLOC_PERFLOG
    alloc_tims.leave(sLog.c_str());
#endif

#else
    THROW_EXCEPTION("The MRPT has been compiled with MRPT_HAS_OPENCV=0 !");
#endif

    MRPT_END
}

/*---------------------------------------------------------------
                    loadFromFile
---------------------------------------------------------------*/
bool CImage::loadFromFile(const std::string& fileName, int isColor)
{
    MRPT_START

#if MRPT_HAS_OPENCV
    IplImage* newImg = cvLoadImage(fileName.c_str(), isColor);
    if (newImg != nullptr)
    {
        releaseIpl();
        img = newImg;
        return true;
    }
    else
    {
        return false;
    }
#else
    THROW_EXCEPTION("The MRPT has been compiled with MRPT_HAS_OPENCV=0 !");
#endif
    MRPT_END
}

/*---------------------------------------------------------------
                    saveToFile
---------------------------------------------------------------*/
bool CImage::saveToFile(const std::string& fileName, int jpeg_quality) const
{
    MRPT_START
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);

#if MRPT_OPENCV_VERSION_NUM > 0x110
    int p[3];
    p[0] = CV_IMWRITE_JPEG_QUALITY;
    p[1] = jpeg_quality;
    p[2] = 0;
    return (0 != cvSaveImage(fileName.c_str(), img, p));
#else
    return (0 != cvSaveImage(fileName.c_str(), img));
#endif
#else
    THROW_EXCEPTION("The MRPT has been compiled with MRPT_HAS_OPENCV=0 !");
#endif
    MRPT_END
}

/*---------------------------------------------------------------
                    loadFromIplImage
---------------------------------------------------------------*/
void CImage::loadFromIplImage(void* iplImage)
{
    MRPT_START
    ASSERT_(iplImage != nullptr);
    releaseIpl();
    if (iplImage)
    {
#if MRPT_HAS_OPENCV
        img = cvCloneImage((IplImage*)iplImage);
#else
        THROW_EXCEPTION("The MRPT has been compiled with MRPT_HAS_OPENCV=0 !");
#endif
    }
    MRPT_END
}

/*---------------------------------------------------------------
                    setFromIplImageReadOnly
---------------------------------------------------------------*/
void CImage::setFromIplImageReadOnly(void* iplImage)
{
    MRPT_START
    releaseIpl();
#if MRPT_HAS_OPENCV
    ASSERT_(iplImage != nullptr);
    ASSERTMSG_(iplImage != this->img, "Trying to assign read-only to itself.");

    img = (IplImage*)iplImage;
#else
    if (iplImage)
    {
        THROW_EXCEPTION("The MRPT has been compiled with MRPT_HAS_OPENCV=0 !");
    }
#endif
    m_imgIsReadOnly = true;
    m_imgIsExternalStorage = false;
    MRPT_END
}

/*---------------------------------------------------------------
                    setFromIplImage
---------------------------------------------------------------*/
void CImage::setFromIplImage(void* iplImage)
{
    MRPT_START

    releaseIpl();
    if (iplImage)
    {
#if MRPT_HAS_OPENCV
        img = (IplImage*)iplImage;
#else
        THROW_EXCEPTION("The MRPT has been compiled with MRPT_HAS_OPENCV=0 !");
#endif
    }
    m_imgIsReadOnly = false;
    m_imgIsExternalStorage = false;

    MRPT_END
}

/*---------------------------------------------------------------
                    loadFromMemoryBuffer
---------------------------------------------------------------*/
void CImage::loadFromMemoryBuffer(
    unsigned int width, unsigned int height, bool color,
    unsigned char* rawpixels, bool swapRedBlue)
{
    MRPT_START

#if MRPT_HAS_OPENCV
    resize(width, height, color ? 3 : 1, true);
    m_imgIsReadOnly = false;
    m_imgIsExternalStorage = false;

    if (color && swapRedBlue)
    {
        // Do copy & swap at once:
        unsigned char* ptr_src = rawpixels;
        unsigned char* ptr_dest =
            reinterpret_cast<unsigned char*>(((IplImage*)img)->imageData);
        const int bytes_per_row_out = ((IplImage*)img)->widthStep;

        for (int h = height; h--;)
        {
            for (unsigned int i = 0; i < width;
                 i++, ptr_src += 3, ptr_dest += 3)
            {
                unsigned char t0 = ptr_src[0], t1 = ptr_src[1], t2 = ptr_src[2];
                ptr_dest[2] = t0;
                ptr_dest[1] = t1;
                ptr_dest[0] = t2;
            }
            ptr_dest += bytes_per_row_out - width * 3;
        }
    }
    else
    {
        if (((IplImage*)img)->widthStep ==
            ((IplImage*)img)->width * ((IplImage*)img)->nChannels)
        {
            // Copy the image data:
            memcpy(
                ((IplImage*)img)->imageData, rawpixels,
                ((IplImage*)img)->imageSize);
        }
        else
        {
            // Copy the image row by row:
            unsigned char* ptr_src = rawpixels;
            unsigned char* ptr_dest =
                reinterpret_cast<unsigned char*>(((IplImage*)img)->imageData);
            int bytes_per_row = width * (color ? 3 : 1);
            int bytes_per_row_out = ((IplImage*)img)->widthStep;
            for (unsigned int y = 0; y < height; y++)
            {
                memcpy(ptr_dest, ptr_src, bytes_per_row);
                ptr_src += bytes_per_row;
                ptr_dest += bytes_per_row_out;
            }
        }
    }
#else
    THROW_EXCEPTION("The MRPT has been compiled with MRPT_HAS_OPENCV=0 !");
#endif
    MRPT_END
}

/*---------------------------------------------------------------
                    operator()
---------------------------------------------------------------*/
unsigned char* CImage::operator()(
    unsigned int col, unsigned int row, unsigned int channel) const
{
#if MRPT_HAS_OPENCV

#if defined(_DEBUG) || (MRPT_ALWAYS_CHECKS_DEBUG)
    MRPT_START
#endif

    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    IplImage* ipl = ((IplImage*)img);

#if defined(_DEBUG) || (MRPT_ALWAYS_CHECKS_DEBUG)
    ASSERT_(ipl);
    if (row >= (unsigned int)ipl->height || col >= (unsigned int)ipl->width ||
        channel >= (unsigned int)ipl->nChannels)
    {
        THROW_EXCEPTION(
            format(
                "Pixel coordinates/channel out of bounds: row=%u/%u col=%u/%u "
                "chan=%u/%u",
                row, ipl->height, col, ipl->width, channel, ipl->nChannels));
    }
#endif

    return (unsigned char*)&ipl
        ->imageData[row * ipl->widthStep + col * ipl->nChannels + channel];
#if defined(_DEBUG) || (MRPT_ALWAYS_CHECKS_DEBUG)
    MRPT_END
#endif

#else
    THROW_EXCEPTION("MRPT was compiled without OpenCV");
#endif
}

/*---------------------------------------------------------------
                    get_unsafe()
---------------------------------------------------------------*/
unsigned char* CImage::get_unsafe(
    unsigned int col, unsigned int row, unsigned int channel) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    IplImage* ipl = ((IplImage*)img);
    return (unsigned char*)&ipl
        ->imageData[row * ipl->widthStep + col * ipl->nChannels + channel];
#else
    return nullptr;
#endif
}

uint8_t CImage::serializeGetVersion() const
{
#if !MRPT_HAS_OPENCV
    return 100;
#else
    return 8;
#endif
}
void CImage::serializeTo(mrpt::serialization::CArchive& out) const
{
#if !MRPT_HAS_OPENCV
    out << m_imgIsExternalStorage;
    if (m_imgIsExternalStorage) out << m_externalFile;
// Nothing else to serialize!
#else
    {
        // Added in version 6: possibility of being stored offline:
        out << m_imgIsExternalStorage;

        if (m_imgIsExternalStorage)
        {
            out << m_externalFile;
        }
        else
        {  // Normal image loaded in memory:
            ASSERT_(img != nullptr);

            const bool hasColor = isColor();

            out << hasColor;

            // Version >2: Color->JPEG, GrayScale->BYTE's array!
            if (!hasColor)
            {
                // GRAY-SCALE: Raw bytes:
                // Version 3: ZIP compression!
                // Version 4: Skip zip if the image size <= 16Kb
                int32_t width = ((IplImage*)img)->width;
                int32_t height = ((IplImage*)img)->height;
                int32_t origin = ((IplImage*)img)->origin;
                int32_t imageSize = ((IplImage*)img)->imageSize;

                out << width << height << origin << imageSize;

                // Version 5: Use CImage::DISABLE_ZIP_COMPRESSION
                bool imageStoredAsZip =
                    !CImage::DISABLE_ZIP_COMPRESSION && (imageSize > 16 * 1024);

                out << imageStoredAsZip;

                // Version 4: Skip zip if the image size <= 16Kb
                if (imageStoredAsZip)
                {
                    std::vector<unsigned char> tempBuf;
                    mrpt::io::zip::compress(
                        ((IplImage*)img)->imageData,  // Data
                        ((IplImage*)img)->imageSize,  // Size
                        tempBuf);

                    int32_t zipDataLen = (int32_t)tempBuf.size();

                    out << zipDataLen;

                    out.WriteBuffer(&tempBuf[0], tempBuf.size());
                    tempBuf.clear();
                }
                else
                {
                    out.WriteBuffer(
                        ((IplImage*)img)->imageData,
                        ((IplImage*)img)->imageSize);
                }
            }
            else
            {
                // COLOR: High quality JPEG image

                // v7: If size is 0xN or Nx0, don't call "saveToStreamAsJPEG"!!
                const int32_t width = ((IplImage*)img)->width;
                const int32_t height = ((IplImage*)img)->height;

                // v8: If DISABLE_JPEG_COMPRESSION
                if (!CImage::DISABLE_JPEG_COMPRESSION)
                {
                    // normal behavior: compress images:
                    out << width << height;

                    if (width >= 1 && height >= 1)
                    {
                        // Save to temporary memory stream:
                        mrpt::io::CMemoryStream aux;
                        saveToStreamAsJPEG(
                            aux, CImage::SERIALIZATION_JPEG_QUALITY);

                        const uint32_t nBytes =
                            static_cast<uint32_t>(aux.getTotalBytesCount());

                        out << nBytes;
                        out.WriteBuffer(aux.getRawBufferData(), nBytes);
                    }
                }
                else
                {  // (New in v8)
                    // Don't JPEG-compress behavior:
                    // Use negative image sizes to signal this behavior:
                    const int32_t neg_width = -width;
                    const int32_t neg_height = -height;

                    out << neg_width << neg_height;

                    // Dump raw image data:
                    const IplImage* ipl = static_cast<const IplImage*>(img);
                    const size_t bytes_per_row = ipl->width * 3;

                    out.WriteBuffer(
                        &ipl->imageData[0], bytes_per_row * ipl->height);
                }
            }
        }  // end m_imgIsExternalStorage=false
    }
#endif
}

void CImage::serializeFrom(mrpt::serialization::CArchive& in, uint8_t version)
{
#if !MRPT_HAS_OPENCV
    if (version == 100)
    {
        in >> m_imgIsExternalStorage;
        if (m_imgIsExternalStorage)
            in >> m_externalFile;
        else
        {
            THROW_EXCEPTION(
                "[CImage] Cannot deserialize image since MRPT has been "
                "compiled without OpenCV");
        }
    }
#else
    releaseIpl();  // First, free current image.

    switch (version)
    {
        case 100:  // Saved from an MRPT build without OpenCV:
        {
            in >> m_imgIsExternalStorage;
            if (m_imgIsExternalStorage) in >> m_externalFile;
        }
        break;
        case 0:
        {
            uint32_t width, height, nChannels, imgLength;
            uint8_t originTopLeft;

            in >> width >> height >> nChannels >> originTopLeft >> imgLength;

            changeSize(width, height, nChannels, originTopLeft != 0);
            in.ReadBuffer(((IplImage*)img)->imageData, imgLength);
        }
        break;
        case 1:
        {
            // Version 1: High quality JPEG image
            mrpt::io::CMemoryStream aux;
            uint32_t nBytes;
            in >> nBytes;

            aux.changeSize(nBytes + 10);

            in.ReadBuffer(aux.getRawBufferData(), nBytes);

            aux.Seek(0);

            loadFromStreamAsJPEG(aux);
        }
        break;
        case 2:
        case 3:
        case 4:
        case 5:
        case 6:
        case 7:
        case 8:
        {
            // Version 6:   m_imgIsExternalStorage ??
            if (version >= 6)
                in >> m_imgIsExternalStorage;
            else
                m_imgIsExternalStorage = false;

            if (m_imgIsExternalStorage)
            {
                // Just the file name:
                in >> m_externalFile;
            }
            else
            {  // Normal, the whole image data:

                // Version 2: Color->JPEG, GrayScale->BYTE's array!
                uint8_t hasColor;
                in >> hasColor;
                if (!hasColor)
                {
                    // GRAY SCALE:
                    int32_t width, height, origin, imageSize;
                    in >> width >> height >> origin >> imageSize;

                    changeSize(width, height, 1, origin == 0);
                    ASSERT_(imageSize == ((IplImage*)img)->imageSize);

                    if (version == 2)
                    {
                        // RAW BYTES:
                        in.ReadBuffer(((IplImage*)img)->imageData, imageSize);
                    }
                    else
                    {
                        // Version 3: ZIP compression!
                        bool imageIsZIP = true;

                        // Version 4: Skip zip if the image size <= 16Kb
                        // Version 5: Use CImage::DISABLE_ZIP_COMPRESSION
                        if (version == 4 && imageSize <= 16 * 1024)
                            imageIsZIP = false;

                        if (version >= 5)
                        {
                            // It is stored int the stream:
                            in >> imageIsZIP;
                        }

                        if (imageIsZIP)
                        {
                            uint32_t zipDataLen;
                            in >> zipDataLen;

#if 0
                        size_t outDataBufferSize = imageSize;
                        size_t outDataActualSize;
                        mrpt::io::zip::decompress(
                            in, zipDataLen, ((IplImage*)img)->imageData,
                            outDataBufferSize, outDataActualSize);
                        ASSERT_(outDataActualSize == outDataBufferSize);
#else
                            MRPT_TODO("Implement deserialization case:");
                            THROW_EXCEPTION("Implement mising method");
#endif
                        }
                        else
                        {
                            // Raw bytes:
                            in.ReadBuffer(
                                ((IplImage*)img)->imageData,
                                ((IplImage*)img)->imageSize);
                        }
                    }
                }
                else
                {
                    bool loadJPEG = true;

                    if (version >= 7)
                    {
                        int32_t width, height;
                        in >> width >> height;

                        if (width >= 1 && height >= 1)
                        {
                            loadJPEG = true;
                        }
                        else
                        {
                            loadJPEG = false;

                            if (width < 0 && height < 0)
                            {
                                // v8: raw image:
                                const int32_t real_w = -width;
                                const int32_t real_h = -height;

                                this->changeSize(real_w, real_h, 3, true);

                                const IplImage* ipl =
                                    static_cast<const IplImage*>(img);
                                const size_t bytes_per_row = ipl->width * 3;
                                for (int y = 0; y < ipl->height; y++)
                                {
                                    const size_t nRead = in.ReadBuffer(
                                        &ipl->imageData[y * ipl->widthStep],
                                        bytes_per_row);
                                    if (nRead != bytes_per_row)
                                        THROW_EXCEPTION(
                                            "Error: Truncated data stream "
                                            "while parsing raw image?")
                                }
                            }
                            else
                            {
                                // it's a 0xN or Nx0 image: just resize and load
                                // nothing:
                                this->changeSize(width, height, 3, true);
                            }
                        }
                    }

                    // COLOR IMAGE: JPEG
                    if (loadJPEG)
                    {
                        mrpt::io::CMemoryStream aux;
                        uint32_t nBytes;
                        in >> nBytes;
                        aux.changeSize(nBytes + 10);
                        in.ReadBuffer(aux.getRawBufferData(), nBytes);
                        aux.Seek(0);
                        loadFromStreamAsJPEG(aux);
                    }
                }
            }
        }
        break;
        default:
            MRPT_THROW_UNKNOWN_SERIALIZATION_VERSION(version)
    };
#endif
}

/*---------------------------------------------------------------
Implements the writing to a mxArray for Matlab
---------------------------------------------------------------*/
#if MRPT_HAS_MATLAB
// Add to implement mexplus::from template specialization
IMPLEMENTS_MEXPLUS_FROM(mrpt::img::CImage)
#endif

mxArray* CImage::writeToMatlab() const
{
#if MRPT_HAS_MATLAB
    cv::Mat cvImg = cv::cvarrToMat(this->getAs<IplImage>());
    return mexplus::from(cvImg);
#else
    THROW_EXCEPTION("MRPT built without MATLAB/Mex support");
#endif
}

/*---------------------------------------------------------------
                    getSize
---------------------------------------------------------------*/
void CImage::getSize(TImageSize& s) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    s.x = ((IplImage*)img)->width;
    s.y = ((IplImage*)img)->height;
#endif
}

/*---------------------------------------------------------------
                    getWidth
---------------------------------------------------------------*/
size_t CImage::getWidth() const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    return ((IplImage*)img)->width;
#else
    return 0;
#endif
}

/*---------------------------------------------------------------
                    getRowStride
---------------------------------------------------------------*/
size_t CImage::getRowStride() const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    return ((IplImage*)img)->widthStep;
#else
    return 0;
#endif
}

/*---------------------------------------------------------------
                    getWidth
---------------------------------------------------------------*/
size_t CImage::getHeight() const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    return ((IplImage*)img)->height;
#else
    return 0;
#endif
}

/*---------------------------------------------------------------
                    isColor
---------------------------------------------------------------*/
bool CImage::isColor() const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    return ((IplImage*)img)->nChannels > 1;
#else
    return false;
#endif
}

/*---------------------------------------------------------------
                    getChannelCount
---------------------------------------------------------------*/
TImageChannels CImage::getChannelCount() const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    return static_cast<unsigned int>(((IplImage*)img)->nChannels);
#else
    return 0;
#endif
}

/*---------------------------------------------------------------
                    isOriginTopLeft
---------------------------------------------------------------*/
bool CImage::isOriginTopLeft() const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    return ((IplImage*)img)->origin == 0;
#else
    THROW_EXCEPTION("MRPT compiled without OpenCV");
#endif
}

/*---------------------------------------------------------------
                    getAsFloat
---------------------------------------------------------------*/
float CImage::getAsFloat(
    unsigned int col, unsigned int row, unsigned int channel) const
{
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    // [0,255]->[0,1]
    return (*(*this)(col, row, channel)) / 255.0f;
}

/*---------------------------------------------------------------
                    getAsFloat
---------------------------------------------------------------*/
float CImage::getAsFloat(unsigned int col, unsigned int row) const
{
    // Is a RGB image??
    if (isColor())
    {
        // Luminance: Y = 0.3R + 0.59G + 0.11B
        unsigned char* pixels = (*this)(col, row, 0);
        return (pixels[0] * 0.3f + pixels[1] * 0.59f + pixels[2] * 0.11f) /
               255.0f;
    }
    else
    {
        // [0,255]->[0,1]
        return (*(*this)(col, row, 0 /* Channel 0:Gray level */)) / 255.0f;
    }
}

/*---------------------------------------------------------------
                    getMaxAsFloat
---------------------------------------------------------------*/
float CImage::getMaxAsFloat() const
{
    int x, y, cx = getWidth(), cy = getHeight();

    float maxPixel = 0;

    for (x = 0; x < cx; x++)
        for (y = 0; y < cy; y++) maxPixel = max(maxPixel, getAsFloat(x, y));

    return maxPixel;
}

/*---------------------------------------------------------------
                    grayscale
---------------------------------------------------------------*/
CImage CImage::grayscale() const
{
    CImage ret;
    grayscale(ret);
    return ret;
}

// Auxiliary function for both ::grayscale() and ::grayscaleInPlace()
#if MRPT_HAS_OPENCV
IplImage* ipl_to_grayscale(const IplImage* img_src)
{
    IplImage* img_dest =
        cvCreateImage(cvSize(img_src->width, img_src->height), IPL_DEPTH_8U, 1);
    img_dest->origin = img_src->origin;

// If possible, use SSE optimized version:
#if MRPT_HAS_SSE3
    if (is_aligned<16>(img_src->imageData) && (img_src->width & 0xF) == 0 &&
        img_src->widthStep == img_src->width * img_src->nChannels &&
        img_dest->widthStep == img_dest->width * img_dest->nChannels)
    {
        ASSERT_(is_aligned<16>(img_dest->imageData));
        image_SSSE3_bgr_to_gray_8u(
            (const uint8_t*)img_src->imageData, (uint8_t*)img_dest->imageData,
            img_src->width, img_src->height);
        return img_dest;
    }
#endif

    // OpenCV Method:
    cvCvtColor(img_src, img_dest, CV_BGR2GRAY);
    return img_dest;
}
#endif

/*---------------------------------------------------------------
                    grayscale
---------------------------------------------------------------*/
void CImage::grayscale(CImage& ret) const
{
#if MRPT_HAS_OPENCV
    // The image is already grayscale??
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    const IplImage* ipl = this->getAs<const IplImage>();
    ASSERT_(ipl);
    if (ipl->nChannels == 1)
    {
        ret = *this;
        return;
    }
    else
    {
        // Convert to a single luminance channel image
        ret.setFromIplImage(ipl_to_grayscale(ipl));
    }
#endif
}

/*---------------------------------------------------------------
                    grayscaleInPlace
---------------------------------------------------------------*/
void CImage::grayscaleInPlace()
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    const IplImage* ipl = this->getAs<const IplImage>();
    ASSERT_(ipl);
    if (ipl->nChannels == 1) return;  // Already done.

    setFromIplImage(ipl_to_grayscale(ipl));
#endif
}

/*---------------------------------------------------------------
                    scaleHalf
---------------------------------------------------------------*/
void CImage::scaleHalf(CImage& out) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    // Get this image size:
    const IplImage* img_src = ((IplImage*)img);
    const int w = img_src->width;
    const int h = img_src->height;

    // Create target image:
    IplImage* img_dest =
        cvCreateImage(cvSize(w >> 1, h >> 1), IPL_DEPTH_8U, img_src->nChannels);
    img_dest->origin = img_src->origin;
    memcpy(img_dest->colorModel, img_src->colorModel, 4);
    memcpy(img_dest->channelSeq, img_src->channelSeq, 4);
    img_dest->dataOrder = img_src->dataOrder;

// If possible, use SSE optimized version:
#if MRPT_HAS_SSE3
    if (img_src->nChannels == 3 && is_aligned<16>(img_src->imageData) &&
        is_aligned<16>(img_dest->imageData) && (w & 0xF) == 0 &&
        img_src->widthStep == img_src->width * img_src->nChannels &&
        img_dest->widthStep == img_dest->width * img_dest->nChannels)
    {
        image_SSSE3_scale_half_3c8u(
            (const uint8_t*)img_src->imageData, (uint8_t*)img_dest->imageData,
            w, h);
        out.setFromIplImage(img_dest);
        return;
    }
#endif

#if MRPT_HAS_SSE2
    if (img_src->nChannels == 1 && is_aligned<16>(img_src->imageData) &&
        is_aligned<16>(img_dest->imageData) && (w & 0xF) == 0 &&
        img_src->widthStep == img_src->width * img_src->nChannels &&
        img_dest->widthStep == img_dest->width * img_dest->nChannels)
    {
        image_SSE2_scale_half_1c8u(
            (const uint8_t*)img_src->imageData, (uint8_t*)img_dest->imageData,
            w, h);

        out.setFromIplImage(img_dest);
        return;
    }
#endif

    // Fall back to slow method:
    cvResize(img_src, img_dest, IMG_INTERP_NN);
    out.setFromIplImage(img_dest);
#endif
}

/*---------------------------------------------------------------
                    scaleHalfSmooth
---------------------------------------------------------------*/
void CImage::scaleHalfSmooth(CImage& out) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    // Get this image size:
    const IplImage* img_src = ((IplImage*)img);
    const int w = img_src->width;
    const int h = img_src->height;

    // Create target image:
    IplImage* img_dest =
        cvCreateImage(cvSize(w >> 1, h >> 1), IPL_DEPTH_8U, img_src->nChannels);
    img_dest->origin = img_src->origin;
    memcpy(img_dest->colorModel, img_src->colorModel, 4);
    memcpy(img_dest->channelSeq, img_src->channelSeq, 4);
    img_dest->dataOrder = img_src->dataOrder;

// If possible, use SSE optimized version:
#if MRPT_HAS_SSE2
    if (img_src->nChannels == 1 && is_aligned<16>(img_src->imageData) &&
        is_aligned<16>(img_dest->imageData) && (w & 0xF) == 0 &&
        img_src->widthStep == img_src->width * img_src->nChannels &&
        img_dest->widthStep == img_dest->width * img_dest->nChannels)
    {
        image_SSE2_scale_half_smooth_1c8u(
            (const uint8_t*)img_src->imageData, (uint8_t*)img_dest->imageData,
            w, h);

        out.setFromIplImage(img_dest);
        return;
    }
#endif

    // Fall back to slow method:
    cvResize(img_src, img_dest, IMG_INTERP_LINEAR);
    out.setFromIplImage(img_dest);
#endif
}

/*---------------------------------------------------------------
                    scaleDouble
---------------------------------------------------------------*/
void CImage::scaleDouble(CImage& out) const
{
    out = *this;
    const TImageSize siz = this->getSize();
    out.scaleImage(siz.x * 2, siz.y * 2);
}

/*---------------------------------------------------------------
                getChannelsOrder
---------------------------------------------------------------*/
const char* CImage::getChannelsOrder() const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img);
    return ((IplImage*)img)->channelSeq;
#else
    THROW_EXCEPTION("MRPT compiled without OpenCV");
#endif
}

/*---------------------------------------------------------------
            loadFromMemoryBuffer
---------------------------------------------------------------*/
void CImage::loadFromMemoryBuffer(
    unsigned int width, unsigned int height, unsigned int bytesPerRow,
    unsigned char* red, unsigned char* green, unsigned char* blue)
{
#if MRPT_HAS_OPENCV
    MRPT_START

    // Fill in the IPL structure:
    changeSize(width, height, 3, true);

    // Copy the image data:
    for (unsigned int y = 0; y < height; y++)
    {
        // The target pixels:
        unsigned char* dest = (unsigned char*)((IplImage*)img)->imageData +
                              ((IplImage*)img)->widthStep * y;

        // Source channels:
        unsigned char* srcR = red + bytesPerRow * y;
        unsigned char* srcG = green + bytesPerRow * y;
        unsigned char* srcB = blue + bytesPerRow * y;

        for (unsigned int x = 0; x < width; x++)
        {
            *(dest++) = *(srcB++);
            *(dest++) = *(srcG++);
            *(dest++) = *(srcR++);
        }  // end of x
    }  // end of y

    MRPT_END
#endif
}

/*---------------------------------------------------------------
                    setOriginTopLeft
---------------------------------------------------------------*/
void CImage::setOriginTopLeft(bool val)
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img);
    ((IplImage*)img)->origin = val ? 0 : 1;
#endif
}

/*---------------------------------------------------------------
                    setPixel
---------------------------------------------------------------*/
void CImage::setPixel(int x, int y, size_t color)
{
#if MRPT_HAS_OPENCV

#if defined(_DEBUG) || (MRPT_ALWAYS_CHECKS_DEBUG)
    MRPT_START
#endif

    makeSureImageIsLoaded();  // For delayed loaded images stored externally

    IplImage* ipl = ((IplImage*)img);

#if defined(_DEBUG) || (MRPT_ALWAYS_CHECKS_DEBUG)
    ASSERT_(ipl);
#endif

    if (x >= 0 && y >= 0 && y < ipl->height && x < ipl->width)
    {
        // The pixel coordinates is valid:
        if (ipl->nChannels == 1)
        {
            *((unsigned char*)&ipl->imageData[y * ipl->widthStep + x]) =
                (unsigned char)color;
        }
        else
        {
#if defined(_DEBUG) || (MRPT_ALWAYS_CHECKS_DEBUG)
            ASSERT_(ipl->nChannels == 3);
            if (ipl->dataOrder != 0)
                THROW_EXCEPTION(
                    "Please, use interleaved images like normal people!!! :-)");
#endif
            unsigned char* dest =
                (unsigned char*)&ipl->imageData[y * ipl->widthStep + 3 * x];
            unsigned char* src = (unsigned char*)&color;

            // Copy the color:
            *dest++ = *src++;  // R
            *dest++ = *src++;  // G
            *dest++ = *src++;  // B
        }
    }

#if defined(_DEBUG) || (MRPT_ALWAYS_CHECKS_DEBUG)
    MRPT_END
#endif

#endif
}

/*---------------------------------------------------------------
                    line
---------------------------------------------------------------*/
void CImage::line(
    int x0, int y0, int x1, int y1, const mrpt::img::TColor color,
    unsigned int width, TPenStyle penStyle)
{
#if MRPT_HAS_OPENCV
    MRPT_UNUSED_PARAM(penStyle);
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    IplImage* ipl = ((IplImage*)img);
    ASSERT_(ipl);

    cvLine(
        ipl, cvPoint(x0, y0), cvPoint(x1, y1),
        CV_RGB(color.R, color.G, color.B), width);
#endif
}

/*---------------------------------------------------------------
                    drawCircle
---------------------------------------------------------------*/
void CImage::drawCircle(
    int x, int y, int radius, const mrpt::img::TColor& color,
    unsigned int width)
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    IplImage* ipl = ((IplImage*)img);
    ASSERT_(ipl);

    cvCircle(
        ipl, cvPoint(x, y), radius, CV_RGB(color.R, color.G, color.B), width);
#endif
}  // end

/*---------------------------------------------------------------
                                           update_patch
--------------------------------------------------------------*/
void CImage::update_patch(
    const CImage& patch, const unsigned int col_, const unsigned int row_)
{
#if MRPT_HAS_OPENCV
    IplImage* ipl_int = ((IplImage*)img);
    IplImage* ipl_ext = ((IplImage*)patch.img);
    ASSERT_(ipl_int);
    ASSERT_(ipl_ext);
    // We check that patch do not jut out of the image.
    if (row_ + ipl_ext->height > getHeight() ||
        col_ + ipl_ext->width > getWidth())
    {
        THROW_EXCEPTION("Error : Patch jut out of image");
    }
    for (unsigned int i = 0; i < patch.getHeight(); i++)
    {
        memcpy(
            &ipl_int->imageData[(i + row_) * ipl_int->widthStep +
                                col_ * ipl_int->nChannels],
            &ipl_ext->imageData[i * ipl_ext->widthStep], ipl_ext->widthStep);
    }
#endif
}

/*---------------------------------------------------------------
                    extract_patch
---------------------------------------------------------------*/
void CImage::extract_patch(
    CImage& patch, const unsigned int col_, const unsigned int row_,
    const unsigned int col_num, const unsigned int row_num) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally

    IplImage* ipl_int = ((IplImage*)img);
    ASSERT_(ipl_int);

    if ((ipl_int->width < (int)(col_ + col_num)) ||
        (ipl_int->height < (int)(row_ + row_num)))
    {
        THROW_EXCEPTION(
            format(
                "Trying to extract patch out of image boundaries: Image "
                "size=%ix%i, Patch size=%ux%u, extraction location=(%u,%u)",
                ipl_int->width, ipl_int->height, col_num, row_num, col_, row_))
    }

    patch.resize(col_num, row_num, ((IplImage*)img)->nChannels, true);
    IplImage* ipl_ext = ((IplImage*)patch.img);
    ASSERT_(ipl_ext);

    for (unsigned int i = 0; i < row_num; i++)
    {
        memcpy(
            &ipl_ext->imageData[i * ipl_ext->widthStep],
            &ipl_int->imageData[(i + row_) * ipl_int->widthStep +
                                col_ * ipl_int->nChannels],
            ipl_ext->widthStep);
    }

#endif
}

/*---------------------------------------------------------------
                    correlate
---------------------------------------------------------------*/
float CImage::correlate(
    const CImage& img2, int width_init, int height_init) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally

    if ((img2.getWidth() + width_init > getWidth()) |
        (img2.getHeight() + height_init > getHeight()))
        THROW_EXCEPTION("Correlation Error!, image to correlate out of bounds");

    unsigned int i, j;
    float x1, x2;
    float syy = 0.0f, sxy = 0.0f, sxx = 0.0f, m1 = 0.0f, m2 = 0.0f,
          n = (float)(img2.getHeight() * img2.getWidth());
    //  IplImage *ipl1 = (*this).img;
    //  IplImage *ipl2 = img2.img;

    // find the means
    for (i = 0; i < img2.getHeight(); i++)
    {
        for (j = 0; j < img2.getWidth(); j++)
        {
            m1 += *(*this)(
                j + width_init,
                i + height_init);  //(double)(ipl1->imageData[i*ipl1->widthStep
            //+ j ]);
            m2 += *img2(
                j, i);  //(double)(ipl2->imageData[i*ipl2->widthStep + j ]);
        }  //[ row * ipl->widthStep +  col * ipl->nChannels +  channel ];
    }
    m1 /= n;
    m2 /= n;

    for (i = 0; i < img2.getHeight(); i++)
    {
        for (j = 0; j < img2.getWidth(); j++)
        {
            x1 = *(*this)(j + width_init, i + height_init) -
                 m1;  //(double)(ipl1->imageData[i*ipl1->widthStep + j]) - m1;
            x2 = *img2(j, i) -
                 m2;  //(double)(ipl2->imageData[i*ipl2->widthStep + j]) - m2;
            sxx += x1 * x1;
            syy += x2 * x2;
            sxy += x1 * x2;
        }
    }

    return sxy / sqrt(sxx * syy);
#else
    return 0;
#endif
}

/*---------------------------------------------------------------
                cross_correlation
---------------------------------------------------------------*/
void CImage::cross_correlation(
    const CImage& patch_img, size_t& x_max, size_t& y_max, double& max_val,
    int x_search_ini, int y_search_ini, int x_search_size, int y_search_size,
    CImage* out_corr_image) const
{
    MRPT_START

    makeSureImageIsLoaded();  // For delayed loaded images stored externally

#if MRPT_HAS_OPENCV
    double mini;
    CvPoint min_point, max_point;

    bool entireImg =
        (x_search_ini < 0 || y_search_ini < 0 || x_search_size < 0 ||
         y_search_size < 0);

    const IplImage *im, *patch_im;

    if (this->isColor() && patch_img.isColor())
    {
        const IplImage* im_ = this->getAs<IplImage>();
        const IplImage* patch_im_ = patch_img.getAs<IplImage>();

        IplImage* aux = cvCreateImage(cvGetSize(im_), 8, 1);
        IplImage* aux2 = cvCreateImage(cvGetSize(patch_im_), 8, 1);
        cvCvtColor(im_, aux, CV_BGR2GRAY);
        cvCvtColor(patch_im_, aux2, CV_BGR2GRAY);
        im = aux;
        patch_im = aux2;
    }
    else
    {
        im = this->getAs<IplImage>();
        patch_im = patch_img.getAs<IplImage>();
    }

    if (entireImg)
    {
        x_search_size = im->width - patch_im->width;
        y_search_size = im->height - patch_im->height;
    }

    // JLBC: Perhaps is better to raise the exception always??
    if ((x_search_ini + x_search_size + patch_im->width - 1) > im->width)
        x_search_size -=
            (x_search_ini + x_search_size + patch_im->width - 1) - im->width;

    if ((y_search_ini + y_search_size + patch_im->height - 1) > im->height)
        y_search_size -=
            (y_search_ini + y_search_size + patch_im->height - 1) - im->height;

    ASSERT_((x_search_ini + x_search_size + patch_im->width - 1) <= im->width);
    ASSERT_(
        (y_search_ini + y_search_size + patch_im->height - 1) <= im->height);
    IplImage* result = cvCreateImage(
        cvSize(x_search_size + 1, y_search_size + 1), IPL_DEPTH_32F, 1);

    const IplImage* ipl_ext;

    if (!entireImg)
    {
        IplImage* aux = cvCreateImage(
            cvSize(
                patch_im->width + x_search_size,
                patch_im->height + y_search_size),
            IPL_DEPTH_8U, 1);
        for (unsigned int i = 0; i < (unsigned int)y_search_size; i++)
        {
            memcpy(
                &aux->imageData[i * aux->widthStep],
                &im->imageData[(i + y_search_ini) * im->widthStep +
                               x_search_ini * im->nChannels],
                aux->width * aux->nChannels);  // widthStep);  <-- JLBC:
            // widthstep SHOULD NOT be used
            // as the length of each row (the
            // last one may be shorter!!)
        }
        ipl_ext = aux;
    }
    else
    {
        ipl_ext = im;
    }

    // Compute cross correlation:
    cvMatchTemplate(ipl_ext, patch_im, result, CV_TM_CCORR_NORMED);
    // cvMatchTemplate(ipl_ext,patch_im,result,CV_TM_CCOEFF_NORMED);

    // Find the max point:
    cvMinMaxLoc(result, &mini, &max_val, &min_point, &max_point, nullptr);
    x_max = max_point.x + x_search_ini + (round(patch_im->width - 1) / 2);
    y_max = max_point.y + y_search_ini + (round(patch_im->height - 1) / 2);

    // Free memory:
    if (!entireImg)
    {
        IplImage* aux = const_cast<IplImage*>(ipl_ext);
        cvReleaseImage(&aux);
        ipl_ext = nullptr;
    }

    // Leave output image?
    if (out_corr_image)
        out_corr_image->setFromIplImage(result);
    else
        cvReleaseImage(&result);
#else
    THROW_EXCEPTION("The MRPT has been compiled with MRPT_HAS_OPENCV=0 !");
#endif

    MRPT_END
}

/*---------------------------------------------------------------
                    normalize
---------------------------------------------------------------*/
void CImage::normalize()
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    IplImage* ipl = getAs<IplImage>();  // Source Image
    ASSERT_(ipl);
    ASSERTMSG_(
        ipl->nChannels == 1,
        "CImage::normalize() only defined for grayscale images.");

    uint8_t min_ = 255, max_ = 1;
    for (int y = 0; y < ipl->height; y++)
    {
        const uint8_t* ptr = reinterpret_cast<const uint8_t*>(
            ipl->imageData + y * ipl->widthStep);
        for (int x = 0; x < ipl->width; x++)
        {
            const uint8_t val = *ptr++;
            if (min_ > val) min_ = val;
            if (max_ < val) max_ = val;
        }
    }

    // Compute scale factor & build convert look-up-table:
    const double s = 255.0 / ((double)max_ - (double)min_);
    uint8_t lut[256];
    for (int v = 0; v < 256; v++) lut[v] = static_cast<uint8_t>((v - min_) * s);

    // Apply LUT:
    for (int y = 0; y < ipl->height; y++)
    {
        uint8_t* ptr =
            reinterpret_cast<uint8_t*>(ipl->imageData + y * ipl->widthStep);
        for (int x = 0; x < ipl->width; x++)
        {
            *ptr = lut[*ptr];
            ptr++;
        }
    }
#endif
}

/*---------------------------------------------------------------
                    getAsMatrix
---------------------------------------------------------------*/
void CImage::getAsMatrix(
    CMatrixFloat& outMatrix, bool doResize, int x_min, int y_min, int x_max,
    int y_max) const
{
#if MRPT_HAS_OPENCV
    MRPT_START

    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img);

    // Set sizes:
    if (x_max == -1) x_max = ((IplImage*)img)->width - 1;
    if (y_max == -1) y_max = ((IplImage*)img)->height - 1;

    ASSERT_(x_min >= 0 && x_min < ((IplImage*)img)->width && x_min < x_max);
    ASSERT_(y_min >= 0 && y_min < ((IplImage*)img)->height && y_min < y_max);

    int lx = (x_max - x_min + 1);
    int ly = (y_max - y_min + 1);

    if (doResize || (int)outMatrix.rows() < ly || (int)outMatrix.cols() < lx)
        outMatrix.setSize(y_max - y_min + 1, x_max - x_min + 1);

    if (isColor())
    {
        // Luminance: Y = 0.3R + 0.59G + 0.11B
        for (int y = 0; y < ly; y++)
        {
            unsigned char* pixels = this->get_unsafe(x_min, y_min + y, 0);
            float aux;
            for (int x = 0; x < lx; x++)
            {
                aux = *pixels++ * 0.3f * (1.0f / 255);
                aux += *pixels++ * 0.59f * (1.0f / 255);
                aux += *pixels++ * 0.11f * (1.0f / 255);
                outMatrix.set_unsafe(y, x, aux);
            }
        }
    }
    else
    {
        for (int y = 0; y < ly; y++)
        {
            unsigned char* pixels = this->get_unsafe(x_min, y_min + y, 0);
            for (int x = 0; x < lx; x++)
                outMatrix.set_unsafe(y, x, (*pixels++) * (1.0f / 255));
        }
    }

    MRPT_END
#endif
}

/*---------------------------------------------------------------
                    getAsRGBMatrices
---------------------------------------------------------------*/
void CImage::getAsRGBMatrices(
    mrpt::math::CMatrixFloat& outMatrixR, mrpt::math::CMatrixFloat& outMatrixG,
    mrpt::math::CMatrixFloat& outMatrixB, bool doResize, int x_min, int y_min,
    int x_max, int y_max) const
{
#if MRPT_HAS_OPENCV
    MRPT_START

    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img);

    // Set sizes:
    if (x_max == -1) x_max = ((IplImage*)img)->width - 1;
    if (y_max == -1) y_max = ((IplImage*)img)->height - 1;

    ASSERT_(x_min >= 0 && x_min < ((IplImage*)img)->width && x_min < x_max);
    ASSERT_(y_min >= 0 && y_min < ((IplImage*)img)->height && y_min < y_max);

    int lx = (x_max - x_min + 1);
    int ly = (y_max - y_min + 1);

    if (doResize || (int)outMatrixR.rows() < ly || (int)outMatrixR.cols() < lx)
        outMatrixR.setSize(y_max - y_min + 1, x_max - x_min + 1);
    if (doResize || (int)outMatrixG.rows() < ly || (int)outMatrixG.cols() < lx)
        outMatrixG.setSize(y_max - y_min + 1, x_max - x_min + 1);
    if (doResize || (int)outMatrixB.rows() < ly || (int)outMatrixB.cols() < lx)
        outMatrixB.setSize(y_max - y_min + 1, x_max - x_min + 1);

    if (isColor())
    {
        for (int y = 0; y < ly; y++)
        {
            unsigned char* pixels = this->get_unsafe(x_min, y_min + y, 0);
            float aux;
            for (int x = 0; x < lx; x++)
            {
                aux = *pixels++ * (1.0f / 255);
                outMatrixR.set_unsafe(y, x, aux);
                aux = *pixels++ * (1.0f / 255);
                outMatrixG.set_unsafe(y, x, aux);
                aux = *pixels++ * (1.0f / 255);
                outMatrixB.set_unsafe(y, x, aux);
            }
        }
    }
    else
    {
        for (int y = 0; y < ly; y++)
        {
            unsigned char* pixels = this->get_unsafe(x_min, y_min + y, 0);
            for (int x = 0; x < lx; x++)
            {
                outMatrixR.set_unsafe(y, x, (*pixels) * (1.0f / 255));
                outMatrixG.set_unsafe(y, x, (*pixels) * (1.0f / 255));
                outMatrixB.set_unsafe(y, x, (*pixels++) * (1.0f / 255));
            }
        }
    }

    MRPT_END
#endif
}

/*---------------------------------------------------------------
                    cross_correlation_FFT
---------------------------------------------------------------*/
void CImage::cross_correlation_FFT(
    const CImage& in_img, CMatrixFloat& out_corr, int u_search_ini,
    int v_search_ini, int u_search_size, int v_search_size, float biasThisImg,
    float biasInImg) const
{
    MRPT_START

    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img);

    // Set limits:
    if (u_search_ini == -1) u_search_ini = 0;
    if (v_search_ini == -1) v_search_ini = 0;
    if (u_search_size == -1) u_search_size = getWidth();
    if (v_search_size == -1) v_search_size = getHeight();

    int u_search_end = u_search_ini + u_search_size - 1;
    int v_search_end = v_search_ini + v_search_size - 1;

    ASSERT_(u_search_end < (int)getWidth());
    ASSERT_(v_search_end < (int)getHeight());

    // Find smallest valid size:
    size_t x, y;
    size_t actual_lx = max(u_search_size, (int)in_img.getWidth());
    size_t actual_ly = max(v_search_size, (int)in_img.getHeight());
    size_t lx = mrpt::round2up(actual_lx);
    size_t ly = mrpt::round2up(actual_ly);

    //  printf("ly=%u lx=%u\n",ly,lx);

    CMatrix i1(ly, lx), i2(ly, lx);

    // We fill the images with the bias, such as when we substract the bias
    // later on,
    //  those pixels not really occupied by the image really becomes zero:
    i1.fill(biasInImg);
    i2.fill(biasThisImg);

    // Get as matrixes, padded with zeros up to power-of-two sizes:
    getAsMatrix(
        i2, false, u_search_ini, v_search_ini, u_search_ini + u_search_size - 1,
        v_search_ini + v_search_size - 1);
    in_img.getAsMatrix(i1, false);

    // Remove the bias now:
    i2.array() -= biasThisImg;
    i1.array() -= biasInImg;

    // Fill the "padded zeros" with copies of the images:
    //  SAVE_MATRIX(i1); SAVE_MATRIX(i2);

    // FFT:
    CMatrix I1_R, I1_I, I2_R, I2_I, ZEROS(ly, lx);
    math::dft2_complex(i1, ZEROS, I1_R, I1_I);
    math::dft2_complex(i2, ZEROS, I2_R, I2_I);

    //  SAVE_MATRIX(I1_R); SAVE_MATRIX(I1_I);
    //  SAVE_MATRIX(I2_R); SAVE_MATRIX(I2_I);

    // Compute the COMPLEX division of I2 by I1:
    for (y = 0; y < ly; y++)
        for (x = 0; x < lx; x++)
        {
            float r1 = I1_R.get_unsafe(y, x);
            float r2 = I2_R.get_unsafe(y, x);

            float ii1 = I1_I.get_unsafe(y, x);
            float ii2 = I2_I.get_unsafe(y, x);

            float den = square(r1) + square(ii1);
            I2_R.set_unsafe(y, x, (r1 * r2 + ii1 * ii2) / den);
            I2_I.set_unsafe(y, x, (ii2 * r1 - r2 * ii1) / den);
        }

    //  I2_R.saveToTextFile("DIV_R.txt");
    //  I2_I.saveToTextFile("DIV_I.txt");

    // IFFT:
    CMatrix res_R, res_I;
    math::idft2_complex(I2_R, I2_I, res_R, res_I);

    out_corr.setSize(actual_ly, actual_lx);
    for (y = 0; y < actual_ly; y++)
        for (x = 0; x < actual_lx; x++)
            out_corr(y, x) = sqrt(square(res_R(y, x)) + square(res_I(y, x)));

    MRPT_END
}

/*---------------------------------------------------------------
                    getAsMatrixTiled
---------------------------------------------------------------*/
void CImage::getAsMatrixTiled(CMatrix& outMatrix) const
{
#if MRPT_HAS_OPENCV
    MRPT_START

    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img);

    // The size of the matrix:
    size_t matrix_lx = outMatrix.cols();
    size_t matrix_ly = outMatrix.rows();

    if (isColor())
    {
        // Luminance: Y = 0.3R + 0.59G + 0.11B
        for (unsigned int y = 0; y < matrix_ly; y++)
        {
            unsigned char* min_pixels =
                (*this)(0, y % ((IplImage*)img)->height, 0);
            unsigned char* max_pixels =
                min_pixels + ((IplImage*)img)->width * 3;
            unsigned char* pixels = min_pixels;
            float aux;
            for (unsigned int x = 0; x < matrix_lx; x++)
            {
                aux = *pixels++ * 0.30f;
                aux += *pixels++ * 0.59f;
                aux += *pixels++ * 0.11f;
                outMatrix.set_unsafe(y, x, aux);
                if (pixels >= max_pixels) pixels = min_pixels;
            }
        }
    }
    else
    {
        for (unsigned int y = 0; y < matrix_ly; y++)
        {
            unsigned char* min_pixels =
                (*this)(0, y % ((IplImage*)img)->height, 0);
            unsigned char* max_pixels = min_pixels + ((IplImage*)img)->width;
            unsigned char* pixels = min_pixels;
            for (unsigned int x = 0; x < matrix_lx; x++)
            {
                outMatrix.set_unsafe(y, x, *pixels++);
                if (pixels >= max_pixels) pixels = min_pixels;
            }
        }
    }

    MRPT_END
#endif
}

/*---------------------------------------------------------------
                    setExternalStorage
---------------------------------------------------------------*/
void CImage::setExternalStorage(const std::string& fileName) noexcept
{
    releaseIpl();
    m_externalFile = fileName;
    m_imgIsExternalStorage = true;
}

/*---------------------------------------------------------------
                    unload
---------------------------------------------------------------*/
void CImage::unload() const noexcept
{
    if (m_imgIsExternalStorage)
        const_cast<CImage*>(this)->releaseIpl(
            true);  // Do NOT mark the image as NON external
}

/*---------------------------------------------------------------
                    releaseIpl
---------------------------------------------------------------*/
void CImage::releaseIpl(bool thisIsExternalImgUnload) noexcept
{
#if MRPT_HAS_OPENCV
    if (img && !m_imgIsReadOnly)
    {
        IplImage* ptr = (IplImage*)img;
        cvReleaseImage(&ptr);
    }
    img = nullptr;
    m_imgIsReadOnly = false;
    if (!thisIsExternalImgUnload)
    {
        m_imgIsExternalStorage = false;
        m_externalFile = string();
    }
#endif
}

/*---------------------------------------------------------------
            makeSureImageIsLoaded
---------------------------------------------------------------*/
void CImage::makeSureImageIsLoaded() const
{
    if (img != nullptr) return;  // OK, continue

    if (m_imgIsExternalStorage)
    {
        // Load the file:
        string wholeFile;
        getExternalStorageFileAbsolutePath(wholeFile);

        const std::string tmpFile = m_externalFile;

        bool ret = const_cast<CImage*>(this)->loadFromFile(wholeFile);

        // These are removed by "loadFromFile", and that's good, just fix it
        // here and carry on.
        m_imgIsExternalStorage = true;
        m_externalFile = tmpFile;

        if (!ret)
            THROW_TYPED_EXCEPTION_FMT(
                CExceptionExternalImageNotFound,
                "Error loading externally-stored image from: %s",
                wholeFile.c_str());
    }
    else
        THROW_EXCEPTION("img is nullptr in a non-externally stored image.");
}

/*---------------------------------------------------------------
            getExternalStorageFileAbsolutePath
---------------------------------------------------------------*/
void CImage::getExternalStorageFileAbsolutePath(std::string& out_path) const
{
    ASSERT_(m_externalFile.size() > 2);

    if (m_externalFile[0] == '/' ||
        (m_externalFile[1] == ':' && m_externalFile[2] == '\\'))
    {
        out_path = m_externalFile;
    }
    else
    {
        out_path = IMAGES_PATH_BASE;

        size_t N = IMAGES_PATH_BASE.size() - 1;
        if (IMAGES_PATH_BASE[N] != '/' && IMAGES_PATH_BASE[N] != '\\')
            out_path += "/";

        out_path += m_externalFile;
    }
}

/*---------------------------------------------------------------
            flipVertical
---------------------------------------------------------------*/
void CImage::flipVertical(bool also_swapRB)
{
#if MRPT_HAS_OPENCV
    IplImage* ptr = (IplImage*)img;
    int options = CV_CVTIMG_FLIP;
    if (also_swapRB) options |= CV_CVTIMG_SWAP_RB;
    cvConvertImage(ptr, ptr, options);
#endif
}

void CImage::flipHorizontal()
{
#if MRPT_HAS_OPENCV
    IplImage* ptr = (IplImage*)img;
    cvFlip(ptr, nullptr, 1);
#endif
}

/*---------------------------------------------------------------
            swapRB
---------------------------------------------------------------*/
void CImage::swapRB()
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    IplImage* ptr = (IplImage*)img;
    cvConvertImage(ptr, ptr, CV_CVTIMG_SWAP_RB);
#endif
}

/*---------------------------------------------------------------
                rectifyImageInPlace
---------------------------------------------------------------*/
void CImage::rectifyImageInPlace(void* mapX, void* mapY)
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);

#if MRPT_OPENCV_VERSION_NUM < 0x200
    THROW_EXCEPTION("This method requires OpenCV 2.0.0 or above.");
#else

    IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg =
        cvCreateImage(cvGetSize(srcImg), srcImg->depth, srcImg->nChannels);

    cv::Mat *_mapX, *_mapY;
    _mapX = static_cast<cv::Mat*>(mapX);
    _mapY = static_cast<cv::Mat*>(mapY);

    IplImage _mapXX = *_mapX;
    IplImage _mapYY = *_mapY;

    cvRemap(srcImg, outImg, &_mapXX, &_mapYY, CV_INTER_CUBIC);
#endif

    releaseIpl();
    img = outImg;
#endif
}

/*---------------------------------------------------------------
                rectifyImageInPlace
---------------------------------------------------------------*/
void CImage::rectifyImageInPlace(const mrpt::img::TCamera& cameraParams)
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    // MRPT -> OpenCV Input Transformation
    IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg;  // Output Image
    outImg = cvCreateImage(cvGetSize(srcImg), srcImg->depth, srcImg->nChannels);

    double aux1[3][3], aux2[1][5];
    const CMatrixDouble33& cameraMatrix = cameraParams.intrinsicParams;

    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++) aux1[i][j] = cameraMatrix(i, j);
    for (int i = 0; i < 5; i++) aux2[0][i] = cameraParams.dist[i];

    CvMat inMat = cvMat(cameraMatrix.rows(), cameraMatrix.cols(), CV_64F, aux1);
    CvMat distM = cvMat(1, 5, CV_64F, aux2);

    // Remove distortion
    cvUndistort2(srcImg, outImg, &inMat, &distM);

    // Assign the output image to the IPLImage pointer within the CImage
    releaseIpl();
    img = outImg;
#endif
}

/*---------------------------------------------------------------
                    rectifyImage
---------------------------------------------------------------*/
void CImage::rectifyImage(
    CImage& out_img, const mrpt::img::TCamera& cameraParams) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    // MRPT -> OpenCV Input Transformation
    const IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg;  // Output Image
    outImg = cvCreateImage(cvGetSize(srcImg), srcImg->depth, srcImg->nChannels);

    double aux1[3][3], aux2[1][5];
    const CMatrixDouble33& cameraMatrix = cameraParams.intrinsicParams;

    for (int i = 0; i < 3; i++)
        for (int j = 0; j < 3; j++) aux1[i][j] = cameraMatrix(i, j);
    for (int i = 0; i < 5; i++) aux2[0][i] = cameraParams.dist[i];

    CvMat inMat = cvMat(cameraMatrix.rows(), cameraMatrix.cols(), CV_64F, aux1);
    CvMat distM = cvMat(1, 5, CV_64F, aux2);

    // Remove distortion
    cvUndistort2(srcImg, outImg, &inMat, &distM);

    // OpenCV -> MRPT Output Transformation
    out_img.loadFromIplImage(outImg);

    // Release Output Image
    cvReleaseImage(&outImg);
#endif
}  // end CImage::rectifyImage

/*---------------------------------------------------------------
                    filterMedian
---------------------------------------------------------------*/
void CImage::filterMedian(CImage& out_img, int W) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    // MRPT -> OpenCV Input Transformation
    const IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg;  // Output Image
    outImg = cvCreateImage(cvGetSize(srcImg), srcImg->depth, srcImg->nChannels);

    // Filter
    cvSmooth(srcImg, outImg, CV_MEDIAN, W);

    outImg->origin = srcImg->origin;

    // OpenCV -> MRPT Output Transformation
    out_img.loadFromIplImage(outImg);

    // Release Output Image
    cvReleaseImage(&outImg);
#endif
}

/*---------------------------------------------------------------
                    filterMedian
---------------------------------------------------------------*/
void CImage::filterMedianInPlace(int W)
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    // MRPT -> OpenCV Input Transformation
    IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg;  // Output Image
    outImg = cvCreateImage(cvGetSize(srcImg), srcImg->depth, srcImg->nChannels);

    // Filter
    cvSmooth(srcImg, outImg, CV_MEDIAN, W);

    outImg->origin = srcImg->origin;

    // Assign the output image to the IPLImage pointer within the CImage
    releaseIpl();
    img = outImg;
#endif
}

/*---------------------------------------------------------------
                    filterGaussian
---------------------------------------------------------------*/
void CImage::filterGaussian(CImage& out_img, int W, int H) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    // MRPT -> OpenCV Input Transformation
    const IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg;  // Output Image
    outImg = cvCreateImage(cvGetSize(srcImg), srcImg->depth, srcImg->nChannels);

    // Filter
    cvSmooth(srcImg, outImg, CV_GAUSSIAN, W, H);

    outImg->origin = srcImg->origin;

    // OpenCV -> MRPT Output Transformation
    out_img.loadFromIplImage(outImg);

    // Release Output Image
    cvReleaseImage(&outImg);
#endif
}

/*---------------------------------------------------------------
                    filterGaussianInPlace
---------------------------------------------------------------*/
void CImage::filterGaussianInPlace(int W, int H)
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    // MRPT -> OpenCV Input Transformation
    IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg;  // Output Image
    outImg = cvCreateImage(cvGetSize(srcImg), srcImg->depth, srcImg->nChannels);

    // Filter
    cvSmooth(srcImg, outImg, CV_GAUSSIAN, W, H);

    outImg->origin = srcImg->origin;

    // Assign the output image to the IPLImage pointer within the CImage
    releaseIpl();
    img = outImg;
#endif
}

/*---------------------------------------------------------------
                    scaleImage
---------------------------------------------------------------*/
void CImage::scaleImage(
    unsigned int width, unsigned int height, TInterpolationMethod interp)
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    IplImage* srcImg = getAs<IplImage>();  // Source Image

    if (static_cast<unsigned int>(srcImg->width) == width &&
        static_cast<unsigned int>(srcImg->height) == height)
        return;

    IplImage* outImg;  // Output Image
    outImg =
        cvCreateImage(cvSize(width, height), srcImg->depth, srcImg->nChannels);

    // Resize:
    cvResize(srcImg, outImg, (int)interp);

    outImg->origin = srcImg->origin;

    // Assign the output image to the IPLImage pointer within the CImage
    releaseIpl();
    img = outImg;
#endif
}

/*---------------------------------------------------------------
                    scaleImage
---------------------------------------------------------------*/
void CImage::scaleImage(
    CImage& out_img, unsigned int width, unsigned int height,
    TInterpolationMethod interp) const
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);
    const IplImage* srcImg = getAs<IplImage>();  // Source Image

    if (static_cast<unsigned int>(srcImg->width) == width &&
        static_cast<unsigned int>(srcImg->height) == height)
    {
        // already at the required size:
        out_img = *this;
        return;
    }

    IplImage* outImg;  // Output Image
    outImg =
        cvCreateImage(cvSize(width, height), srcImg->depth, srcImg->nChannels);

    // Resize:
    cvResize(srcImg, outImg, (int)interp);
    outImg->origin = srcImg->origin;

    // Assign:
    out_img.setFromIplImage(outImg);
#endif
}

/*---------------------------------------------------------------
                    rotateImage
---------------------------------------------------------------*/
void CImage::rotateImage(
    double angle_radians, unsigned int center_x, unsigned int center_y,
    double scale)
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img != nullptr);

    IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg;  // Output Image
    outImg = cvCreateImage(cvGetSize(srcImg), srcImg->depth, srcImg->nChannels);

    // Based on the blog entry:
    // http://blog.weisu.org/2007/12/opencv-image-rotate-and-zoom-rotation.html

    // Apply rotation & scale:
    float m[6];
    CvMat M = cvMat(2, 3, CV_32F, m);

    m[0] = (float)(scale * cos(angle_radians));
    m[1] = (float)(scale * sin(angle_radians));
    m[3] = -m[1];
    m[4] = m[0];
    m[2] = center_x;
    m[5] = center_y;

    cvGetQuadrangleSubPix(srcImg, outImg, &M);

    outImg->origin = srcImg->origin;

    // Assign the output image to the IPLImage pointer within the CImage
    releaseIpl();
    img = outImg;

#endif
}

/** Draw onto this image the detected corners of a chessboard. The length of
 * cornerCoords must be the product of the two check_sizes.
 *
 * \param cornerCoords [IN] The pixel coordinates of all the corners.
 * \param check_size_x [IN] The number of squares, in the X direction
 * \param check_size_y [IN] The number of squares, in the Y direction
 *
 * \return false if the length of cornerCoords is inconsistent (nothing is drawn
 * then).
 */
bool CImage::drawChessboardCorners(
    std::vector<TPixelCoordf>& cornerCoords, unsigned int check_size_x,
    unsigned int check_size_y, unsigned int lines_width, unsigned int r)
{
#if MRPT_HAS_OPENCV

    if (cornerCoords.size() != check_size_x * check_size_y) return false;

    IplImage* ipl = this->getAs<IplImage>();

    unsigned int x, y, i;
    CvPoint prev_pt = cvPoint(0, 0);
    const int line_max = 8;
    CvScalar line_colors[8];

    line_colors[0] = CV_RGB(255, 0, 0);
    line_colors[1] = CV_RGB(255, 128, 0);
    line_colors[2] = CV_RGB(255, 128, 0);
    line_colors[3] = CV_RGB(200, 200, 0);
    line_colors[4] = CV_RGB(0, 255, 0);
    line_colors[5] = CV_RGB(0, 200, 200);
    line_colors[6] = CV_RGB(0, 0, 255);
    line_colors[7] = CV_RGB(255, 0, 255);

    CCanvas::selectTextFont("10x20");

    for (y = 0, i = 0; y < check_size_y; y++)
    {
        CvScalar color = line_colors[y % line_max];
        for (x = 0; x < check_size_x; x++, i++)
        {
            CvPoint pt;
            pt.x = cvRound(cornerCoords[i].x);
            pt.y = cvRound(cornerCoords[i].y);

            if (i != 0) cvLine(ipl, prev_pt, pt, color, lines_width);

            cvLine(
                ipl, cvPoint(pt.x - r, pt.y - r), cvPoint(pt.x + r, pt.y + r),
                color, lines_width);
            cvLine(
                ipl, cvPoint(pt.x - r, pt.y + r), cvPoint(pt.x + r, pt.y - r),
                color, lines_width);

            if (r > 0) cvCircle(ipl, pt, r + 1, color);
            prev_pt = pt;

            // Text label with the corner index in the first and last corners:
            if (i == 0 || i == cornerCoords.size() - 1)
                CCanvas::textOut(
                    pt.x + 5, pt.y - 5, mrpt::format("%u", i),
                    mrpt::img::TColor::blue());
        }
    }

    return true;
#else
    return false;
#endif
}

/** Replaces this grayscale image with a RGB version of it.
 * \sa grayscaleInPlace
 */
void CImage::colorImage(CImage& ret) const
{
#if MRPT_HAS_OPENCV
    if (this->isColor())
    {
        ret = *this;
        return;
    }

    const IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg = cvCreateImage(cvGetSize(srcImg), srcImg->depth, 3);

    cvCvtColor(srcImg, outImg, CV_GRAY2BGR);

    outImg->origin = srcImg->origin;

    // Assign the output image to the IPLImage pointer within the CImage
    ret.setFromIplImage(outImg);
#endif
}

/** Replaces this grayscale image with a RGB version of it.
 * \sa grayscaleInPlace
 */
void CImage::colorImageInPlace()
{
#if MRPT_HAS_OPENCV
    if (this->isColor()) return;

    IplImage* srcImg = getAs<IplImage>();  // Source Image
    IplImage* outImg;  // Output Image
    outImg = cvCreateImage(cvGetSize(srcImg), srcImg->depth, 3);

    cvCvtColor(srcImg, outImg, CV_GRAY2BGR);

    outImg->origin = srcImg->origin;

    // Assign the output image to the IPLImage pointer within the CImage
    releaseIpl();
    img = outImg;
#endif
}

/*---------------------------------------------------------------
                    joinImagesHorz
---------------------------------------------------------------*/
void CImage::joinImagesHorz(const CImage& im1, const CImage& im2)
{
#if MRPT_HAS_OPENCV
    ASSERT_(im1.getHeight() == im2.getHeight());

    const IplImage* _im1 = im1.getAs<IplImage>();
    const IplImage* _im2 = im2.getAs<IplImage>();

    ASSERT_(_im1->depth == _im2->depth && _im1->nChannels == _im2->nChannels);

    IplImage* out = cvCreateImage(
        cvSize(_im1->width + _im2->width, _im1->height), _im1->depth,
        _im1->nChannels);

    cvSetImageROI(out, cvRect(0, 0, _im1->width, _im1->height));
    cvCopy(_im1, out);
    cvSetImageROI(out, cvRect(_im1->width, 0, _im2->width, _im2->height));
    cvCopy(_im2, out);
    cvSetImageROI(out, cvRect(0, 0, out->width, out->height));

    IplImage* out2;
    if ((int)_im1->nChannels != (int)this->getChannelCount())  // Convert the
    // input to the
    // output channel
    // format
    {
        out2 = cvCreateImage(
            cvSize(_im1->width + _im2->width, _im1->height), _im1->depth,
            this->getChannelCount());
        cvCvtColor(out, out2, CV_GRAY2BGR);
        this->setFromIplImageReadOnly(out2);
    }
    else  // Assign the output image to the IPLImage pointer within the CImage
        this->setFromIplImageReadOnly(out);

#endif
}  // end

/*---------------------------------------------------------------
                    equalizeHist
---------------------------------------------------------------*/
void CImage::equalizeHist(CImage& outImg) const
{
#if MRPT_HAS_OPENCV
    // Convert to a single luminance channel image
    const IplImage* srcImg = getAs<IplImage>();  // Source Image
    ASSERT_(srcImg != nullptr);
    outImg.changeSize(srcImg->width, srcImg->height, 1, isOriginTopLeft());

    if (srcImg->nChannels == 1)
    {  // Grayscale:
        cvEqualizeHist(srcImg, outImg.getAs<IplImage>());
    }
    else
    {  // Color:
        IplImage* hsv = cvCreateImage(cvGetSize(srcImg), 8, 3);
        IplImage* h = cvCreateImage(cvGetSize(srcImg), 8, 1);
        IplImage* s = cvCreateImage(cvGetSize(srcImg), 8, 1);
        IplImage* v = cvCreateImage(cvGetSize(srcImg), 8, 1);

        cvCvtColor(srcImg, hsv, CV_BGR2HSV);
        cvSplit(hsv, h, s, v, nullptr);

        cvEqualizeHist(v, v);

        cvMerge(h, s, v, nullptr, hsv);
        cvCvtColor(hsv, outImg.getAs<IplImage>(), CV_HSV2BGR);

        cvReleaseImage(&hsv);
        cvReleaseImage(&h);
        cvReleaseImage(&s);
        cvReleaseImage(&v);
    }

#endif
}

/*---------------------------------------------------------------
                    equalizeHistInPlace
---------------------------------------------------------------*/
void CImage::equalizeHistInPlace()
{
#if MRPT_HAS_OPENCV
    // Convert to a single luminance channel image
    IplImage* srcImg = getAs<IplImage>();  // Source Image
    ASSERT_(srcImg != nullptr);

    IplImage* outImg =
        cvCreateImage(cvGetSize(srcImg), srcImg->depth, srcImg->nChannels);
    outImg->origin = srcImg->origin;

    if (srcImg->nChannels == 1)
    {  // Grayscale:
        cvEqualizeHist(srcImg, outImg);
    }
    else
    {  // Color:
        IplImage* hsv = cvCreateImage(cvGetSize(srcImg), 8, 3);
        IplImage* h = cvCreateImage(cvGetSize(srcImg), 8, 1);
        IplImage* s = cvCreateImage(cvGetSize(srcImg), 8, 1);
        IplImage* v = cvCreateImage(cvGetSize(srcImg), 8, 1);

        cvCvtColor(srcImg, hsv, CV_BGR2HSV);
        cvSplit(hsv, h, s, v, nullptr);

        cvEqualizeHist(v, v);

        cvMerge(h, s, v, nullptr, hsv);
        cvCvtColor(hsv, outImg, CV_HSV2BGR);

        cvReleaseImage(&hsv);
        cvReleaseImage(&h);
        cvReleaseImage(&s);
        cvReleaseImage(&v);
    }

    // Assign the output image to the IPLImage pointer within the CImage
    releaseIpl();
    img = outImg;

#endif
}

template <unsigned int HALF_WIN_SIZE>
void image_KLT_response_template(
    const uint8_t* in, const int widthStep, int x, int y, int32_t& _gxx,
    int32_t& _gyy, int32_t& _gxy)
{
    const unsigned int min_x = x - HALF_WIN_SIZE;
    const unsigned int min_y = y - HALF_WIN_SIZE;

    int32_t gxx = 0;
    int32_t gxy = 0;
    int32_t gyy = 0;

    const unsigned int WIN_SIZE = 1 + 2 * HALF_WIN_SIZE;

    unsigned int yy = min_y;
    for (unsigned int iy = WIN_SIZE; iy; --iy, ++yy)
    {
        const uint8_t* ptr = in + widthStep * yy + min_x;
        unsigned int xx = min_x;
        for (unsigned int ix = WIN_SIZE; ix; --ix, ++xx)
        {
            const int32_t dx = ptr[+1] - ptr[-1];
            const int32_t dy = ptr[+widthStep] - ptr[-widthStep];
            gxx += dx * dx;
            gxy += dx * dy;
            gyy += dy * dy;
        }
    }
    _gxx = gxx;
    _gyy = gyy;
    _gxy = gxy;
}

float CImage::KLT_response(
    const unsigned int x, const unsigned int y,
    const unsigned int half_window_size) const
{
#if MRPT_HAS_OPENCV
    const IplImage* srcImg = this->getAs<IplImage>();
    ASSERT_(srcImg != nullptr);
    ASSERTMSG_(
        srcImg->nChannels == 1,
        "KLT_response only works with grayscale images.");

    const unsigned int img_w = srcImg->width;
    const unsigned int img_h = srcImg->height;
    const int widthStep = srcImg->widthStep;

    // If any of those predefined values worked, do the generic way:
    const unsigned int min_x = x - half_window_size;
    const unsigned int max_x = x + half_window_size;
    const unsigned int min_y = y - half_window_size;
    const unsigned int max_y = y + half_window_size;

    // Since min_* are "unsigned", checking "<" will detect negative numbers:
    ASSERTMSG_(
        min_x < img_w && max_x < img_w && min_y < img_h && max_y < img_h,
        "Window is out of image bounds");

    // Gradient sums: Use integers since they're much faster than
    // doubles/floats!!
    int32_t gxx = 0;
    int32_t gxy = 0;
    int32_t gyy = 0;

    const uint8_t* img_data = reinterpret_cast<const uint8_t*>(
        srcImg->imageData);  //*VERY IMPORTANT*: Use unsigned
    switch (half_window_size)
    {
        case 2:
            image_KLT_response_template<2>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 3:
            image_KLT_response_template<3>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 4:
            image_KLT_response_template<4>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 5:
            image_KLT_response_template<5>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 6:
            image_KLT_response_template<6>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 7:
            image_KLT_response_template<7>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 8:
            image_KLT_response_template<8>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 9:
            image_KLT_response_template<9>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 10:
            image_KLT_response_template<10>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 11:
            image_KLT_response_template<11>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 12:
            image_KLT_response_template<12>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 13:
            image_KLT_response_template<13>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 14:
            image_KLT_response_template<14>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 15:
            image_KLT_response_template<15>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 16:
            image_KLT_response_template<16>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;
        case 32:
            image_KLT_response_template<32>(
                img_data, widthStep, x, y, gxx, gyy, gxy);
            break;

        default:
            for (unsigned int yy = min_y; yy <= max_y; yy++)
            {
                const uint8_t* ptr = img_data + widthStep * yy + min_x;
                for (unsigned int xx = min_x; xx <= max_x; xx++)
                {
                    const int32_t dx = ptr[+1] - ptr[-1];
                    const int32_t dy = ptr[+widthStep] - ptr[-widthStep];
                    gxx += dx * dx;
                    gxy += dx * dy;
                    gyy += dy * dy;
                }
            }
            break;
    }
    // Convert to float's and normalize in the way:
    const float K = 0.5f / ((max_y - min_y + 1) * (max_x - min_x + 1));
    const float Gxx = gxx * K;
    const float Gxy = gxy * K;
    const float Gyy = gyy * K;

    // Return the minimum eigenvalue of:
    //    ( gxx  gxy )
    //    ( gxy  gyy )
    // See, for example: mrpt::math::detail::eigenVectorsMatrix_special_2x2():
    const float t = Gxx + Gyy;  // Trace
    const float de = Gxx * Gyy - Gxy * Gxy;  // Det
    // The smallest eigenvalue is:
    return 0.5f * (t - std::sqrt(t * t - 4.0f * de));
#else
    return 0;
#endif
}

/** Marks the channel ordering in a color image (this doesn't actually modify
 * the image data, just the format description)
 */
void CImage::setChannelsOrder_RGB()
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img);
    strcpy(((IplImage*)img)->channelSeq, "RGB");
#else
    THROW_EXCEPTION("MRPT compiled without OpenCV");
#endif
}

void CImage::setChannelsOrder_BGR()
{
#if MRPT_HAS_OPENCV
    makeSureImageIsLoaded();  // For delayed loaded images stored externally
    ASSERT_(img);
    strcpy(((IplImage*)img)->channelSeq, "BGR");
#else
    THROW_EXCEPTION("MRPT compiled without OpenCV");
#endif
}

// Load from TGA files. Used in loadFromFile()
// Contains code from
// https://github.com/tjohnman/Simple-Targa-Library/blob/master/src/simpleTGA.cpp
// (FreeBSD license)
bool CImage::loadTGA(
    const std::string& fileName, mrpt::img::CImage& out_RGB,
    mrpt::img::CImage& out_alpha)
{
#if MRPT_HAS_OPENCV
    std::fstream stream;
    stream.open(fileName.c_str(), std::fstream::in | std::fstream::binary);
    if (!stream.is_open())
    {
        std::cerr << "[CImage::loadTGA] Couldn't open file '" << fileName
                  << "'.\n";
        return false;
    }

    stream.seekg(0, std::ios_base::end);
    // long length = stream.tellg();
    stream.seekg(0, std::ios_base::beg);

    // Simple uncompressed true-color image
    char dumpBuffer[12];
    char trueColorHeader[] = "\0\0\2\0\0\0\0\0\0\0\0\0";
    stream.read(dumpBuffer, 12);
    if (memcmp(dumpBuffer, trueColorHeader, 12) != 0)
    {
        std::cerr << "[CImage::loadTGA] Unsupported format or invalid file.\n";
        return false;
    }

    unsigned short width, height;
    unsigned char bpp;

    stream.read((char*)&width, 2);
    stream.read((char*)&height, 2);
    bpp = stream.get();
    if (bpp != 32)
    {
        std::cerr << "[CImage::loadTGA] Only 32 bpp format supported!\n";
        return false;
    }

    unsigned char desc;
    desc = stream.get();
    if (desc != 8 && desc != 32)
    {
        std::cerr << "[CImage::loadTGA] Unsupported format or invalid file.\n";
        return false;
    }
    const bool origin_is_low_corner = (desc == 8);

    // Data section
    std::vector<uint8_t> bytes(width * height * 4);
    stream.read((char*)&bytes[0], width * height * 4);
    stream.close();

    // Move data to images:
    out_RGB.resize(width, height, CH_RGB, true);
    out_alpha.resize(width, height, CH_GRAY, true);

    size_t idx = 0;
    for (unsigned int r = 0; r < height; r++)
    {
        unsigned int actual_row = origin_is_low_corner ? (height - 1 - r) : r;
        IplImage* ipl = ((IplImage*)out_RGB.img);
        unsigned char* data =
            (unsigned char*)&ipl->imageData[actual_row * ipl->widthStep];

        IplImage* ipl_alpha = ((IplImage*)out_alpha.img);
        unsigned char* data_alpha =
            (unsigned char*)&ipl->imageData[actual_row * ipl_alpha->widthStep];

        for (unsigned int c = 0; c < width; c++)
        {
            *data++ = bytes[idx++];  // R
            *data++ = bytes[idx++];  // G
            *data++ = bytes[idx++];  // B
            *data_alpha++ = bytes[idx++];  // A
        }
    }

    return true;
#else
    return false;
#endif  // MRPT_HAS_OPENCV
}

std::ostream& mrpt::img::operator<<(std::ostream& o, const TPixelCoordf& p)
{
    o << "(" << p.x << "," << p.y << ")";
    return o;
}
std::ostream& mrpt::img::operator<<(std::ostream& o, const TPixelCoord& p)
{
    o << "(" << p.x << "," << p.y << ")";
    return o;
}