二級考試C++實例:單通道圖像的直方圖

字號:

今天學習opencv中圖像的直方圖,重點研究單通道圖像直方圖生成的過程,以下是直方圖生成的代碼:
    #include "cv.h"
    #include "highgui.h"
    #include
    #include
    int main( int argc, char** argv )
    {
    IplImage *src = 0;
    IplImage *histimg = 0;
    CvHistogram *hist = 0;
    int hdims = 50; // 劃分HIST的個數,越高越精確
    float hranges_arr[] = {0,255};
    float* hranges = hranges_arr;
    int bin_w;
    float max_val;
    int i;
    if( argc != 2 || (src="http://pic02.newdu.com/uploads/202503/20/img_default_show5657.png" data-src=cvLoadImage(argv[1], 0)) == NULL) // 強制轉為灰度圖像
    return -1;
    cvNamedWindow( "Histogram", 0 );
    cvNamedWindow( "src", CV_WINDOW_AUTOSIZE);
    hist = cvCreateHist( 1, &hdims, CV_HIST_ARRAY, &hranges, 1 ); // 計算直方圖
    histimg = cvCreateImage( cvSize(320,200), 8, 3 );
    cvZero( histimg );
    cvCalcHist( &src, hist, 0, 0 ); // 計算直方圖
    cvGetMinMaxHistValue( hist, 0, &max_val, 0, 0 ); // 只找值
    cvConvertScale( hist->bins,
    hist->bins, max_val ? 255. / max_val : 0., 0 ); // 縮放 bin 到區(qū)間 [0,255]
    cvZero( histimg );
    bin_w = histimg->width / hdims; // hdims: 條的個數,則 bin_w 為條的寬度
    // 畫直方圖
    for( i = 0; i < hdims; i++ )
    {
    double val = ( cvGetReal1D(hist->bins,i)*histimg->height/255 );
    CvScalar color = CV_RGB(255,255,0); //(hsv2rgb(i*180.f/hdims);
    cvRectangle( histimg, cvPoint(i*bin_w,histimg->height),
    cvPoint((i+1)*bin_w,(int)(histimg->height - val)),
    color, 1, 8, 0 );
    }
    cvShowImage( "src", src);
    cvShowImage( "Histogram", histimg );
    cvWaitKey(0);
    cvDestroyWindow("src");
    cvDestroyWindow("Histogram");
    cvReleaseImage( &src );
    cvReleaseImage( &histimg );
    cvReleaseHist ( &hist );
    return 0;
    }