c++ - Detecting specific rectangular part of the image -

i trying find rectangular regions image , not getting required result , getting results slow , due visiting every channel , approach should use detect licence plate of vehicle , should need detect rectangular region first , apply ocr or should directly apply algorithm given

thanks

lpr (license plate recognition) has solid , practical solution if search little bit more. solution contains edge detection(e.g. sobel), thresholding(on sobel), morphological operations(find close edges, letters have), contours(to rectangle them) , optional classifier validate results(filter false positives).