int main(int argc, char** argv)
{
if (argc != 2) {
help(argv);
return 1;
}
std::string arg = argv[1];
VideoCapture capture(arg);
if (!capture.isOpened()){
capture.open(atoi(arg.c_str()));
}
if (!capture.isOpened()) {
cerr << "Failed to open a video device or video file!\n" << endl;
help(argv);
return 1;
}
char filename[200];
Mat frame1;
Mat frame2;
Mat frame3;
Mat frame4;
capture >> frame1;
sprintf(filename,"frame%.3d.jpg",1);
imwrite(filename,frame1);
frame3 = imread(filename);
capture.set(CV_CAP_PROP_POS_FRAMES, 100);
capture >> frame2;
sprintf(filename,"frame%.3d.jpg",2);
imwrite(filename,frame2);
frame4 = imread(filename);
cout << (double)cmpHistOfHSV(frame1, frame2) << endl;
cout << (double)partOfCmpHist(frame1, frame2) << endl;
cout << cmpHistOfHSV(frame3, frame4) << endl;
cout << partOfCmpHist(frame3, frame4) << endl;
return 0;
}
the output:
0
0
4074.85
6790.25
why, the video frame is different the img?
Appendix：
double cmpHistOfHSV(Mat src_base1, Mat src_base2)
{
const int HL_RANGE = 0;
const int HR_RANGE = 256;
const int SL_RANGE = 0;
const int SR_RANGE =
180;
180;
const int H_BINS = 12;//50
const int S_BINS = 6;//60
Mat hsv_base1, hsv_base2;
// Convert to HSV
cvtColor(src_base1, hsv_base1, CV_BGR2HSV);
cvtColor(src_base2, hsv_base2, CV_BGR2HSV);
//30 bins for Hue, 32 for Saturation
int h_bins = H_BINS;
int s_bins = S_BINS;
int histSize[] = {h_bins, s_bins};
//hue varies from 0 to 256, saturation from 0 to 180
float h_ranges[] = {HL_RANGE, HR_RANGE};
float s_ranges[] = {SL_RANGE, SR_RANGE};
const float *ranges[] = {h_ranges, s_ranges};
//Use the 0th and 1th channels
int channels[] = {0, 1};
//Histogram
MatND hist_base1;
MatND hist_base2;
//Calculate the histogram for HSV images
calcHist(&hsv_base1, 1, channels, Mat(), hist_base1, 2, histSize, ranges, true, false);
normalize(hist_base1, hist_base1, 0, 1, NORM_MINMAX, -1, Mat());
calcHist(&hsv_base2, 1, channels, Mat(), hist_base2, 2, histSize, ranges, true, false);
normalize(hist_base2, hist_base2, 0, 1, NORM_MINMAX, -1, Mat());
double base_base = compareHist(hist_base1, hist_base2, 1);
return base_base;
}
}
