python识别视频黑屏或者低清晰度

import os
import numpy as np
import cv2 as cv
from skimage import filters, io


class DetectException(Exception):
    pass


class DetectionUtil:

    DARK_THRES_PIXEL = 20
    DARK_THRES_PERCENT = 0.90
    QUALITY_THRES = 30


    def unqualified_detection(self, image_path):
        """black screen or low quality."""
        # image = cv.imread(image_path)
        try:
            image = io.imread(image_path)
        except Exception as e:
            raise DetectException(e)
        image = image[:, :, ::-1]
        gray_image = cv.cvtColor(image, cv.COLOR_BGR2GRAY)
        row, col = gray_image.shape[:2]
        pixel_count = row*col

        dark_condition = (gray_image <self.DARK_THRES_PIXEL)
        dark_array = gray_image[dark_condition]
        if dark_array.size / pixel_count >= self.DARK_THRES_PERCENT:
            return True
        quality = self.genengrad_detection(image)
        if quality < self.QUALITY_THRES:
            return True
        return False

    def _preprocess_image(self, image):
        re_img = cv.resize(image, (800, 900), interpolation=cv.INTER_CUBIC)
        gray_image = cv.cvtColor(re_img, cv.COLOR_BGR2GRAY)
        image_matrix = np.matrix(gray_image)
        return image_matrix

    def genengrad_detection(self, image):
        matrix =self._preprocess_image(image)
        return np.sqrt(np.sum(filters.sobel(matrix)**2))


if __name__ == "__main__":
    print(DetectionUtil().unqualified_detection(r"视频封面地址"))
    #true为黑屏或者低分辨率