写出ssim的python代码

以下是使用Python实现SSIM的示例代码：

import numpy as np
import cv2

def SSIM(img1, img2):
    # Compute the mean of the two input images
    mu1 = np.mean(img1)
    mu2 = np.mean(img2)

    # Compute the variance of the two input images
    var1 = np.var(img1)
    var2 = np.var(img2)

    # Compute the covariance of the two input images
    cov = np.mean((img1 - mu1) * (img2 - mu2))

    # Compute the SSIM value
    c1 = (0.01 * 255) ** 2
    c2 = (0.03 * 255) ** 2
    ssim = ((2 * mu1 * mu2 + c1) * (2 * cov + c2)) / ((mu1 ** 2 + mu2 ** 2 + c1) * (var1 + var2 + c2))

    return ssim

# Load two images
img1 = cv2.imread("image1.jpg")
img2 = cv2.imread("image2.jpg")

# Convert the images to gray scale
img1_gray = cv2.cvtColor(img1, cv2.COLOR_BGR2GRAY)
img2_gray = cv2.cvtColor(img2, cv2.COLOR_BGR2GRAY)

# Compute the SSIM value of the two images
ssim_value = SSIM(img1_gray, img2_gray)

print("The SSIM value of the two images is:", ssim_value)

请注意，这只是一个简单的示例代码，并且可能需要根据您的实际情况进行修改。此外，您需要确保已安装必要的Python库，例如OpenCV和NumPy。