mse - MSE & PSNR - 最大像素

Question

问：我有一张 512x512 的封面图片。使用下面的代码。我将为max_pixel行输入什么？

import cv2
import numpy as np


def PSNR(original, compressed):
    mse = np.mean((original - compressed) ** 2)
    print(f"MSE value is {mse}")
    if (mse == 0):  # MSE is zero means no noise is present in the signal .
        # Therefore PSNR have no importance.
        return 100
    max_pixel = 255.0
    psnr = 20 * log10(max_pixel / sqrt(mse))
    return psnr


def main():
    original = cv2.imread("lena512.png")
    compressed = cv2.imread("lenastego.png", 1)
    value = PSNR(original, compressed)
    print(f"PSNR value is {value} dB")

if __name__ == "__main__":
    main()