Python cv2 模块，MORPH_GRADIENT 实例源码

def recognize_text(original):
    idcard = original
    gray = cv2.cvtColor(idcard, cv2.COLOR_BGR2GRAY)

    # Morphological gradient:
    kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (5, 5))
    opening = cv2.morphologyEx(gray, cv2.MORPH_GRADIENT, kernel)

    # Binarization
    ret, binarization = cv2.threshold(opening, 0.0, 255.0, cv2.THRESH_BINARY | cv2.THRESH_OTSU)

    # Connected horizontally oriented regions
    kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (9, 1))
    connected = cv2.morphologyEx(binarization, cv2.MORPH_CLOSE, kernel)

    # find countours
    _, contours, hierarchy = cv2.findContours(
        connected, cv2.RETR_CCOMP, cv2.CHAIN_APPROX_SIMPLE
    )
    return contours, hierarchy