c++ - opencv face detection loop parameters -

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i need explanation of following loop face detection in opencv 

videocapture capture("dsc_0772.avi"); //-1, 0, 1 device id  mat cap_img,gray_img; vector<rect> faces, eyes; while(1) {     capture >> cap_img;     waitkey(10);     cvtcolor(cap_img, gray_img, cv_bgr2gray);     cv::equalizehist(gray_img,gray_img);     face_cascade.detectmultiscale(gray_img, faces, 1.1, 5, cv_haar_scale_image | cv_haar_do_canny_pruning, cvsize(0,0), cvsize(300,300));     for(int i=0; < faces.size();i++)     {         point pt1(faces[i].x+faces[i].width, faces[i].y+faces[i].height);         point pt2(faces[i].x,faces[i].y);          rectangle(cap_img, pt1, pt2, cvscalar(0,255,0), 2, 8, 0);     }

i don't understand faces[i].x , other loop parameters

how selected face detection

thanks help

faces std::vector of rect. loop going through each rect in vector , creating 2 points. rect stores not x , y(of top left corner) height , width of rectangle. faces[i].x+faces[i].width taking x coordinate of rectangle plus width , faces[i].y+faces[i].height taking y coordinate of rectangle plus height. getting opposite corner of rectangle. feeding points plus image rectangle() function.


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