在OpenCV中在图像中绘制矩形

Question

To find out the maximum and minimum pixel value of a gray scale image is

     IplImage* src = cvLoadImage(argv[1],0);

     double min_val;
     double max_val;
     CvPoint minLoc;
     CvPoint maxLoc;
     cvMinMaxLoc(dst,&minVal,&maxVal, &minLoc, &maxLoc);
     printf("Min val %f \n",minVal);
     printf("Max Val %f \n",maxVal);
     printf("Min location %d \n",minLoc);
     printf("Max location %d \n",maxLoc);

I am using OpenCV C API. Now I want to draw a rectangle around the maximum pixel location (maxLoc) with cvRectangle(CvArr* img, CvPoint pt1, CvPoint pt2, CvScalar color, int thickness=1, int lineType=8, int shift=0) but I don't know what will be the parameters of rectangle vertices ie pt1 and pt2. Will the other 3 parameters be always 1, 8 and 0. Can anybody help me with the parameters.

Answer 1

the two corners of your rectangle will be displaced say 1 pixel above and below the location of the max pixel.

so cvRectangle(img, minLoc+cvPoint(- 1,- 1), minLoc+cvPoint(1,1), 255, 2) will draw a rectangle 1px araound the point, with the rect having a border thickness of 2px

Yes, If the other parameters are not specified, they default to their values 1,8,0