Matlab在图像中画标记框

   img = imread(\'M1.JPG\');
   figure;
   hold on;
   imshow(img);
   hold off;
   px = 1200;
   py = 2000;
   step = 200;
   x1 = px - step;
   x2 = px + step;
   y1 = py - step;
   y2 = py + step;
   hold on;
   rectx = [x1 x2 x2 x1 x1];
   recty = [y1 y1 y2 y2 y1];
   plot(rectx, recty, \'linewidth\',2);
   hold off;

效果

   img = imread(\'M1.JPG\');
   figure;
   hold on;
   subplot(121);
   imshow(img);
   hold off;
   px = 1200;
   py = 2000;
   step = 200;
   x1 = px - step;
   x2 = px + step;
   y1 = py - step;
   y2 = py + step;
   hold on;
   rectx = [x1 x2 x2 x1 x1];
   recty = [y1 y1 y2 y2 y1];
   plot(rectx, recty, \'linewidth\',2);
   hold off;
   img2 = imread(\'M2.jpg\');
   hold on;
   subplot(122);
   imshow(img2);
   hold off;
   px = 1200;
   py = 2000;
   step = 200;
   x1 = px - step;
   x2 = px + step;
   y1 = py - step;
   y2 = py + step;
   hold on;
   rectx = [x1 x2 x2 x1 x1];
   recty = [y1 y1 y2 y2 y1];
   plot(rectx, recty, \'linewidth\',2);
   hold off;