WebSVN - OpenCV2-Cookbook - Diff - Rev 3 and 5 - /trunk/Chapter 04/colorhistogram.h


#if !defined COLHISTOGRAM
#define COLHISTOGRAM

#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>

class ColorHistogram {

  private:

    int histSize[3];
        float hranges[2];
    const float* ranges[3];
    int channels[3];

  public:

        ColorHistogram() {

                // Prepare arguments for a color histogram
                histSize[0]= histSize[1]= histSize[2]= 256;
                hranges[0]= 0.0;    // BRG range
                hranges[1]= 255.0;
                ranges[0]= hranges; // all channels have the same range 
                ranges[1]= hranges;
                ranges[2]= hranges;
                channels[0]= 0;         // the three channels 
                channels[1]= 1;
                channels[2]= 2;
        }

        // Computes the histogram.
        cv::MatND getHistogram(const cv::Mat &image) {

                cv::MatND hist;

                // BGR color histogram
                hranges[0]= 0.0;    // BRG range
                hranges[1]= 255.0;
                channels[0]= 0;         // the three channels 
                channels[1]= 1;
                channels[2]= 2;

                // Compute histogram
                cv::calcHist(&image,
                        1,                      // histogram of 1 image only
                        channels,       // the channel used
                        cv::Mat(),      // no mask is used
                        hist,           // the resulting histogram
                        3,                      // it is a 3D histogram
                        histSize,       // number of bins
                        ranges          // pixel value range
                );

                return hist;
        }

        // Computes the histogram.
        cv::SparseMat getSparseHistogram(const cv::Mat &image) {

                cv::SparseMat hist(3,histSize,CV_32F);

                // BGR color histogram
                hranges[0]= 0.0;    // BRG range
                hranges[1]= 255.0;
                channels[0]= 0;         // the three channels 
                channels[1]= 1;
                channels[2]= 2;

                // Compute histogram
                cv::calcHist(&image,
                        1,                      // histogram of 1 image only
                        channels,       // the channel used
                        cv::Mat(),      // no mask is used
                        hist,           // the resulting histogram
                        3,                      // it is a 3D histogram
                        histSize,       // number of bins
                        ranges          // pixel value range
                );

                return hist;
        }

        // Computes the 2D ab histogram.
        // BGR source image is converted to Lab
        cv::MatND getabHistogram(const cv::Mat &image) {

                cv::MatND hist;

                // Convert to Lab color space
                cv::Mat lab;
                cv::cvtColor(image, lab, CV_BGR2Lab);

                // Prepare arguments for a 2D color histogram
                hranges[0]= -128.0;
                hranges[1]= 127.0;
                channels[0]= 1; // the two channels used are ab 
                channels[1]= 2;

                // Compute histogram
                cv::calcHist(&lab,
                        1,                      // histogram of 1 image only
                        channels,       // the channel used
                        cv::Mat(),      // no mask is used
                        hist,           // the resulting histogram
                        2,                      // it is a 2D histogram
                        histSize,       // number of bins
                        ranges          // pixel value range
                );

                return hist;
        }

        // Computes the 1D Hue histogram with a mask.
        // BGR source image is converted to HSV
        cv::MatND getHueHistogram(const cv::Mat &image) {

                cv::MatND hist;

                // Convert to Lab color space
                cv::Mat hue;
                cv::cvtColor(image, hue, CV_BGR2HSV);

                // Prepare arguments for a 1D hue histogram
                hranges[0]= 0.0;
                hranges[1]= 180.0;
                channels[0]= 0; // the hue channel 

                // Compute histogram
                cv::calcHist(&hue,
                        1,                      // histogram of 1 image only
                        channels,       // the channel used
                        cv::Mat(),      // no mask is used
                        hist,           // the resulting histogram
                        1,                      // it is a 1D histogram
                        histSize,       // number of bins
                        ranges          // pixel value range
                );

                return hist;
        }

        cv::Mat colorReduce(const cv::Mat &image, int div=64) {

          int n= static_cast<int>(log(static_cast<double>(div))/log(2.0));
          // mask used to round the pixel value
          uchar mask= 0xFF<<n; // e.g. for div=16, mask= 0xF0

          cv::Mat_<cv::Vec3b>::const_iterator it= image.begin<cv::Vec3b>();
          cv::Mat_<cv::Vec3b>::const_iterator itend= image.end<cv::Vec3b>();

          // Set output image (always 1-channel)
          cv::Mat result(image.rows,image.cols,image.type());
          cv::Mat_<cv::Vec3b>::iterator itr= result.begin<cv::Vec3b>();

          for ( ; it!= itend; ++it, ++itr) {
       
        (*itr)[0]= ((*it)[0]&mask) + div/2;
        (*itr)[1]= ((*it)[1]&mask) + div/2;
        (*itr)[2]= ((*it)[2]&mask) + div/2;
          }

          return result;
}

};


#endif
 

Rev 3	Rev 5
1	#if !defined COLHISTOGRAM	1	#if !defined COLHISTOGRAM
2	#define COLHISTOGRAM	2	#define COLHISTOGRAM
3		3
4	#include <opencv2\core\core.hpp>	4	#include <opencv2/core/core.hpp>
5	#include <opencv2\imgproc\imgproc.hpp>	5	#include <opencv2/imgproc/imgproc.hpp>
6		6
7	class ColorHistogram {	7	class ColorHistogram {
8		8
9	private:	9	private:
10		10
11	int histSize[3];	11	int histSize[3];
12	float hranges[2];	12	float hranges[2];
13	const float* ranges[3];	13	const float* ranges[3];
14	int channels[3];	14	int channels[3];
15		15
16	public:	16	public:
17		17
18	ColorHistogram() {	18	ColorHistogram() {
19		19
20	// Prepare arguments for a color histogram	20	// Prepare arguments for a color histogram
21	histSize[0]= histSize[1]= histSize[2]= 256;	21	histSize[0]= histSize[1]= histSize[2]= 256;
22	hranges[0]= 0.0; // BRG range	22	hranges[0]= 0.0; // BRG range
23	hranges[1]= 255.0;	23	hranges[1]= 255.0;
24	ranges[0]= hranges; // all channels have the same range	24	ranges[0]= hranges; // all channels have the same range
25	ranges[1]= hranges;	25	ranges[1]= hranges;
26	ranges[2]= hranges;	26	ranges[2]= hranges;
27	channels[0]= 0; // the three channels	27	channels[0]= 0; // the three channels
28	channels[1]= 1;	28	channels[1]= 1;
29	channels[2]= 2;	29	channels[2]= 2;
30	}	30	}
31		31
32	// Computes the histogram.	32	// Computes the histogram.
33	cv::MatND getHistogram(const cv::Mat &image) {	33	cv::MatND getHistogram(const cv::Mat &image) {
34		34
35	cv::MatND hist;	35	cv::MatND hist;
36		36
37	// BGR color histogram	37	// BGR color histogram
38	hranges[0]= 0.0; // BRG range	38	hranges[0]= 0.0; // BRG range
39	hranges[1]= 255.0;	39	hranges[1]= 255.0;
40	channels[0]= 0; // the three channels	40	channels[0]= 0; // the three channels
41	channels[1]= 1;	41	channels[1]= 1;
42	channels[2]= 2;	42	channels[2]= 2;
43		43
44	// Compute histogram	44	// Compute histogram
45	cv::calcHist(&image,	45	cv::calcHist(&image,
46	1, // histogram of 1 image only	46	1, // histogram of 1 image only
47	channels, // the channel used	47	channels, // the channel used
48	cv::Mat(), // no mask is used	48	cv::Mat(), // no mask is used
49	hist, // the resulting histogram	49	hist, // the resulting histogram
50	3, // it is a 3D histogram	50	3, // it is a 3D histogram
51	histSize, // number of bins	51	histSize, // number of bins
52	ranges // pixel value range	52	ranges // pixel value range
53	);	53	);
54		54
55	return hist;	55	return hist;
56	}	56	}
57		57
58	// Computes the histogram.	58	// Computes the histogram.
59	cv::SparseMat getSparseHistogram(const cv::Mat &image) {	59	cv::SparseMat getSparseHistogram(const cv::Mat &image) {
60		60
61	cv::SparseMat hist(3,histSize,CV_32F);	61	cv::SparseMat hist(3,histSize,CV_32F);
62		62
63	// BGR color histogram	63	// BGR color histogram
64	hranges[0]= 0.0; // BRG range	64	hranges[0]= 0.0; // BRG range
65	hranges[1]= 255.0;	65	hranges[1]= 255.0;
66	channels[0]= 0; // the three channels	66	channels[0]= 0; // the three channels
67	channels[1]= 1;	67	channels[1]= 1;
68	channels[2]= 2;	68	channels[2]= 2;
69		69
70	// Compute histogram	70	// Compute histogram
71	cv::calcHist(&image,	71	cv::calcHist(&image,
72	1, // histogram of 1 image only	72	1, // histogram of 1 image only
73	channels, // the channel used	73	channels, // the channel used
74	cv::Mat(), // no mask is used	74	cv::Mat(), // no mask is used
75	hist, // the resulting histogram	75	hist, // the resulting histogram
76	3, // it is a 3D histogram	76	3, // it is a 3D histogram
77	histSize, // number of bins	77	histSize, // number of bins
78	ranges // pixel value range	78	ranges // pixel value range
79	);	79	);
80		80
81	return hist;	81	return hist;
82	}	82	}
83		83
84	// Computes the 2D ab histogram.	84	// Computes the 2D ab histogram.
85	// BGR source image is converted to Lab	85	// BGR source image is converted to Lab
86	cv::MatND getabHistogram(const cv::Mat &image) {	86	cv::MatND getabHistogram(const cv::Mat &image) {
87		87
88	cv::MatND hist;	88	cv::MatND hist;
89		89
90	// Convert to Lab color space	90	// Convert to Lab color space
91	cv::Mat lab;	91	cv::Mat lab;
92	cv::cvtColor(image, lab, CV_BGR2Lab);	92	cv::cvtColor(image, lab, CV_BGR2Lab);
93		93
94	// Prepare arguments for a 2D color histogram	94	// Prepare arguments for a 2D color histogram
95	hranges[0]= -128.0;	95	hranges[0]= -128.0;
96	hranges[1]= 127.0;	96	hranges[1]= 127.0;
97	channels[0]= 1; // the two channels used are ab	97	channels[0]= 1; // the two channels used are ab
98	channels[1]= 2;	98	channels[1]= 2;
99		99
100	// Compute histogram	100	// Compute histogram
101	cv::calcHist(&lab,	101	cv::calcHist(&lab,
102	1, // histogram of 1 image only	102	1, // histogram of 1 image only
103	channels, // the channel used	103	channels, // the channel used
104	cv::Mat(), // no mask is used	104	cv::Mat(), // no mask is used
105	hist, // the resulting histogram	105	hist, // the resulting histogram
106	2, // it is a 2D histogram	106	2, // it is a 2D histogram
107	histSize, // number of bins	107	histSize, // number of bins
108	ranges // pixel value range	108	ranges // pixel value range
109	);	109	);
110		110
111	return hist;	111	return hist;
112	}	112	}
113		113
114	// Computes the 1D Hue histogram with a mask.	114	// Computes the 1D Hue histogram with a mask.
115	// BGR source image is converted to HSV	115	// BGR source image is converted to HSV
116	cv::MatND getHueHistogram(const cv::Mat &image) {	116	cv::MatND getHueHistogram(const cv::Mat &image) {
117		117
118	cv::MatND hist;	118	cv::MatND hist;
119		119
120	// Convert to Lab color space	120	// Convert to Lab color space
121	cv::Mat hue;	121	cv::Mat hue;
122	cv::cvtColor(image, hue, CV_BGR2HSV);	122	cv::cvtColor(image, hue, CV_BGR2HSV);
123		123
124	// Prepare arguments for a 1D hue histogram	124	// Prepare arguments for a 1D hue histogram
125	hranges[0]= 0.0;	125	hranges[0]= 0.0;
126	hranges[1]= 180.0;	126	hranges[1]= 180.0;
127	channels[0]= 0; // the hue channel	127	channels[0]= 0; // the hue channel
128		128
129	// Compute histogram	129	// Compute histogram
130	cv::calcHist(&hue,	130	cv::calcHist(&hue,
131	1, // histogram of 1 image only	131	1, // histogram of 1 image only
132	channels, // the channel used	132	channels, // the channel used
133	cv::Mat(), // no mask is used	133	cv::Mat(), // no mask is used
134	hist, // the resulting histogram	134	hist, // the resulting histogram
135	1, // it is a 1D histogram	135	1, // it is a 1D histogram
136	histSize, // number of bins	136	histSize, // number of bins
137	ranges // pixel value range	137	ranges // pixel value range
138	);	138	);
139		139
140	return hist;	140	return hist;
141	}	141	}
142		142
143	cv::Mat colorReduce(const cv::Mat &image, int div=64) {	143	cv::Mat colorReduce(const cv::Mat &image, int div=64) {
144		144
145	int n= static_cast<int>(log(static_cast<double>(div))/log(2.0));	145	int n= static_cast<int>(log(static_cast<double>(div))/log(2.0));
146	// mask used to round the pixel value	146	// mask used to round the pixel value
147	uchar mask= 0xFF<<n; // e.g. for div=16, mask= 0xF0	147	uchar mask= 0xFF<<n; // e.g. for div=16, mask= 0xF0
148		148
149	cv::Mat_<cv::Vec3b>::const_iterator it= image.begin<cv::Vec3b>();	149	cv::Mat_<cv::Vec3b>::const_iterator it= image.begin<cv::Vec3b>();
150	cv::Mat_<cv::Vec3b>::const_iterator itend= image.end<cv::Vec3b>();	150	cv::Mat_<cv::Vec3b>::const_iterator itend= image.end<cv::Vec3b>();
151		151
152	// Set output image (always 1-channel)	152	// Set output image (always 1-channel)
153	cv::Mat result(image.rows,image.cols,image.type());	153	cv::Mat result(image.rows,image.cols,image.type());
154	cv::Mat_<cv::Vec3b>::iterator itr= result.begin<cv::Vec3b>();	154	cv::Mat_<cv::Vec3b>::iterator itr= result.begin<cv::Vec3b>();
155		155
156	for ( ; it!= itend; ++it, ++itr) {	156	for ( ; it!= itend; ++it, ++itr) {
157		157
158	(itr)[0]= ((it)[0]&mask) + div/2;	158	(itr)[0]= ((it)[0]&mask) + div/2;
159	(itr)[1]= ((it)[1]&mask) + div/2;	159	(itr)[1]= ((it)[1]&mask) + div/2;
160	(itr)[2]= ((it)[2]&mask) + div/2;	160	(itr)[2]= ((it)[2]&mask) + div/2;
161	}	161	}
162		162
163	return result;	163	return result;
164	}	164	}
165		165
166	};	166	};
167		167
168		168
169	#endif	169	#endif
170		170

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