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CMappedImage.cpp
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1 /* +---------------------------------------------------------------------------+
2  | Mobile Robot Programming Toolkit (MRPT) |
3  | http://www.mrpt.org/ |
4  | |
5  | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file |
6  | See: http://www.mrpt.org/Authors - All rights reserved. |
7  | Released under BSD License. See details in http://www.mrpt.org/License |
8  +---------------------------------------------------------------------------+ */
9 
10 #include "base-precomp.h" // Precompiled headers
11 
13 #include <mrpt/utils/round.h>
14 
15 using namespace mrpt;
16 using namespace mrpt::utils;
17 using namespace mrpt::math;
18 
19 
20 /*---------------------------------------------------------------
21  Constructor
22  ---------------------------------------------------------------*/
23 CMappedImage::CMappedImage( CImagePtr img, double x0, double x1, double y0, double y1, TInterpolationMethod method ) :
24  m_img( img ),
25  m_x0 (x0),
26  m_x1 (x1),
27  m_y0 (y0),
28  m_y1 (y1),
29  m_pixel_size(0),
30  m_method( method )
31 {
32  m_img->grayscale();
33  if (m_img->isColor())
34  {
35  CImage *new_img = new CImage();
36  m_img->grayscale(*new_img);
37  m_img = CImagePtr( new_img );
38  }
39  changeCoordinates(x0,x1,y0,y1);
40 }
41 
42 /*---------------------------------------------------------------
43  changeCoordinates
44  ---------------------------------------------------------------*/
45 void CMappedImage::changeCoordinates(double x0, double x1, double y0, double y1)
46 {
48  ASSERT_(x0!=x1);
49  ASSERT_(y0!=y1);
50 
51  m_x0 =x0; m_x1 =x1;
52  m_y0 =y0; m_y1 =y1;
53 
54  if (y1<0 || x1<0)
55  {
56  m_x1 = m_img->getWidth()-1;
57  m_y1 = m_img->getHeight()-1;
58  }
59 
60  ASSERT_( m_img->getWidth()>0 && m_img->getHeight() );
61 
62  m_pixel_size = (m_x1-m_x0) / m_img->getWidth();
63 
64  MRPT_END
65 }
66 
67 /*---------------------------------------------------------------
68  getPixel
69  ---------------------------------------------------------------*/
70 double CMappedImage::getPixel(double x,double y ) const
71 {
72  // Image size:
73  const size_t W = m_img->getWidth();
74  const size_t H = m_img->getHeight();
75 
76  // the sub-pixel pixel coordinates:
77  const double px = (x-m_x0)/m_pixel_size;
78  const double py = (y-m_y0)/m_pixel_size;
79 
80  if (px<0 || py<0 || px>W || py>H) { return 0; } // Out of image
81 
82  switch (m_method)
83  {
84  case IMG_INTERP_NN:
85  {
86  // The closest pixel:
87  const int px0 = mrpt::utils::round(px);
88  const int py0 = mrpt::utils::round(py);
89  return static_cast<double>(*m_img->get_unsafe(px0, py0));
90  }
91  break;
92  case IMG_INTERP_LINEAR:
93  {
94  // See: http://en.wikipedia.org/wiki/Bilinear_interpolation
95 
96  // The four pixels around:
97  const int px0 = (int)floor(px);
98  const int px1 = (int)ceil(px);
99  const int py0 = (int)floor(py);
100  const int py1 = (int)ceil(py);
101 
102  const double P11 = static_cast<double>(*m_img->get_unsafe(px0, py0));
103  const double P12 = static_cast<double>(*m_img->get_unsafe(px0, py1));
104  const double P21 = static_cast<double>(*m_img->get_unsafe(px1, py0));
105  const double P22 = static_cast<double>(*m_img->get_unsafe(px1, py1));
106 
107  const double R1 = P11*(px1-px) /* /(px1-px0)*/ + P21*(px-px0) /* /(px1-px0) */;
108  const double R2 = P12*(px1-px) /* /(px1-px0)*/ + P22*(px-px0) /* /(px1-px0) */;
109 
110  return R1 * (py1-py) + R2 * (py-py0);
111  }
112  break;
113 
114  case IMG_INTERP_CUBIC:
115  {
116  THROW_EXCEPTION("TO DO!");
117  }
118  break;
119 
120  case IMG_INTERP_AREA:
121  default:
122  THROW_EXCEPTION("The selected interpolation method is not supported in this method.");
123  };
124 
125 }
126 
Classes for serialization, sockets, ini-file manipulation, streams, list of properties-values, timewatch, extensions to STL.
Definition: zip.h:16
double m_pixel_size
width * pixel_size = (x1-x0)
Definition: CMappedImage.h:29
A class for storing images as grayscale or RGB bitmaps.
Definition: CImage.h:101
#define THROW_EXCEPTION(msg)
void changeCoordinates(double x0, double x1, double y0, double y1)
Changes the coordinates of the image (see constructor for the meaning)
double getPixel(double x, double y) const
Returns the interpolated pixel at the coordinates (x,y), in the range [0,255] (grayscale) If the poin...
This base provides a set of functions for maths stuff.
Definition: CArrayNumeric.h:19
#define MRPT_END
GLint GLvoid * img
Definition: glext.h:3645
TInterpolationMethod
Interpolation methods for images.
Definition: CImage.h:31
#define MRPT_START
This is the global namespace for all Mobile Robot Programming Toolkit (MRPT) libraries.
#define ASSERT_(f)
int round(const T value)
Returns the closer integer (int) to x.
Definition: round.h:26
GLenum GLint GLint y
Definition: glext.h:3516
CMappedImage(CImagePtr img, double x0=0, double x1=-1, double y0=0, double y1=-1, TInterpolationMethod method=IMG_INTERP_LINEAR)
Constructor: Must pass an image (as a smart pointer) and the coordinates of the border.
TInterpolationMethod m_method
Definition: CMappedImage.h:30
GLenum GLint x
Definition: glext.h:3516



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