image_utils.py 文件源码

def find_lines(img, acc_threshold=0.25, should_erode=True):
    if len(img.shape) == 3 and img.shape[2] == 3:  # if it's color
        img = cv2.cvtColor(img, cv2.COLOR_RGB2GRAY)
    img = cv2.GaussianBlur(img, (11, 11), 0)
    img = cv2.adaptiveThreshold(
            img,
            255,
            cv2.ADAPTIVE_THRESH_MEAN_C,
            cv2.THRESH_BINARY,
            5,
            2)

    img = cv2.bitwise_not(img)

    # thresh = 127
    # edges = cv2.threshold(img, thresh, 255, cv2.THRESH_BINARY)[1]
    # edges = cv2.Canny(blur, 500, 500, apertureSize=3)

    if should_erode:
        element = cv2.getStructuringElement(cv2.MORPH_RECT, (4, 4))
        img = cv2.erode(img, element)

    theta = np.pi/2000
    angle_threshold = 2
    horizontal = cv2.HoughLines(
            img,
            1,
            theta,
            int(acc_threshold * img.shape[1]),
            min_theta=np.radians(90 - angle_threshold),
            max_theta=np.radians(90 + angle_threshold))
    vertical = cv2.HoughLines(
            img,
            1,
            theta,
            int(acc_threshold * img.shape[0]),
            min_theta=np.radians(-angle_threshold),
            max_theta=np.radians(angle_threshold),
            )

    horizontal = list(horizontal) if horizontal is not None else []
    vertical = list(vertical) if vertical is not None else []

    horizontal = [line[0] for line in horizontal]
    vertical = [line[0] for line in vertical]

    horizontal = np.asarray(horizontal)
    vertical = np.asarray(vertical)

    return horizontal, vertical