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