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| // entropy(hsv) | |
| // it computes the histogram on a neighborhood | |
| Features::VectImgType Features::Histogram (const VectUcharPointType& pt) | |
| { | |
| VectImgType hist( 3, cv::Mat::zeros(256, 1, CV_8UC1) ); | |
| for (VectUcharPointType::const_iterator it = pt.begin(); | |
| it != pt.end(); | |
| ++it ) | |
| { | |
| const cv::Vec3b& pix = *it; | |
| for( int d = 0; d < 3; d++) | |
| { | |
| cv::Mat& tempHist = hist[d]; | |
| uchar val = pix[d]; | |
| tempHist.at<uchar>( val, static_cast<uchar>( 0 ) ) = tempHist.at<uchar>( val, static_cast<uchar>( 0 ) ) + static_cast<uchar>( 1 ); | |
| } | |
| } | |
| return hist; | |
| } | |
| // it compute the entropy | |
| cv::Vec3f Features::Entropy (const VectUcharPointType& pt, const VectImgType& hist) | |
| { | |
| assert( !pt.empty() ); | |
| size_t N = pt.size(); | |
| const float invN = 1. / static_cast< float >( N ); | |
| cv::Vec3f ent(0., 0., 0.); | |
| for( int d = 0; d < 3; d++) | |
| { | |
| const cv::Mat& Hist = hist[d]; | |
| float entropy = 0.; | |
| for (size_t i = 0; i < N; i++ ) | |
| { | |
| const float val = ( pt[i] )[d]; | |
| const float p = static_cast<float>( Hist.at< uchar >( val, 0 ) ) * invN; | |
| if( p > 0. ) | |
| { | |
| entropy -= p*log(p); | |
| } | |
| else | |
| { | |
| std::cout << "p = 0"<<std::endl; | |
| } | |
| } | |
| ent[d] = entropy; | |
| } | |
| return ent; | |
| } |
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