r_screen_detect.py 文件源码

def screen_position():
    '''
    Returns position of rectangle x,y,w,h if:
        - bounding rectangle is big enough (more than 0.2 % of total captured image)
        - contour's area is more than 70% of the area of the bounding rectangle
    '''
    cap = cv2.VideoCapture(0)
    nb_max_iterations = int(30*ALLOWED_DETECTION_TIME)
    for it in range(nb_max_iterations):
        ret, frame = cap.read()
        mask = detect_color(frame)
        masked_frame = cv2.bitwise_and(frame, frame, mask=mask)
        imgray = cv2.cvtColor(masked_frame, cv2.COLOR_BGR2GRAY)
        contours, hierarchy = cv2.findContours(imgray,cv2.RETR_TREE,cv2.CHAIN_APPROX_NONE)
        contours = sorted(contours, key=lambda x:len(x), reverse=True)
        i = 0
        while(i < len(contours)):
            x,y,w,h = cv2.boundingRect(contours[i])
            rect_cnt = np.array([[[x, y]], [[x+w, y]], [[x+w, y+h]], [[x, y+h]]], dtype=np.int32)
            rect_cnt_area = cv2.contourArea(rect_cnt)
            if(cv2.contourArea(contours[i]) > VALID_AREA_RATIO * rect_cnt_area and \
                    rect_cnt_area > VALID_MIN_AREA and \
                    rect_cnt_area < VALID_MAX_AREA):
                cap.release()
                return x,y,w,h
            else:
                i += 1
    cap.release()
    return -1,-1,-1,-1