Assuming you have read the image using imread
, this should work:
bwImage=~im2bw(img,0.98); %making gray pixels white and (almost) white pixels black
bndBox=regionprops(bwImage,'BoundingBox');
bndBox
will have top-left corner of the bounding box and its width and height stored in the format [corner_x corner_y width height]
.