# -*- coding: utf-8 -*-
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__author__ = '上海色宁'
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import cv2
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import numpy as np
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import time
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import sys
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#相关操作
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#由于使用的高斯函数圆对称，因此相关操作和卷积操作结果相同
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def correlation(img,kernal):
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kernal_heigh = kernal.shape[0]
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kernal_width = kernal.shape[1]
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cor_heigh = img.shape[0] - kernal_heigh + 1
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cor_width = img.shape[1] - kernal_width + 1
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result = np.zeros((cor_heigh, cor_width), dtype=np.float64)
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for i in range(cor_heigh):
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for j in range(cor_width):
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result[i][j] = (img[i:i + kernal_heigh, j:j + kernal_width] * kernal).sum()
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return result
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#产生二维高斯核函数
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#这个函数参考自：https://blog.csdn.net/qq_16013649/article/details/78784791
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def gaussian_2d_kernel(kernel_size=11, sigma=1.5):
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kernel = np.zeros([kernel_size, kernel_size])
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center = kernel_size // 2
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if sigma == 0:
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sigma = ((kernel_size - 1) * 0.5 - 1) * 0.3 + 0.8
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s = 2 * (sigma ** 2)
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sum_val = 0
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for i in range(0, kernel_size):
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for j in range(0, kernel_size):
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x = i - center
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y = j - center
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kernel[i, j] = np.exp(-(x ** 2 + y ** 2) / s)
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sum_val += kernel[i, j]
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sum_val = 1 / sum_val
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return kernel * sum_val
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#ssim模型
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def ssim(distorted_image,original_image,window_size=11,gaussian_sigma=1.5,K1=0.01,K2=0.03,alfa=1,beta=1,gama=1):
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distorted_image=np.array(distorted_image,dtype=np.float64)
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original_image=np.array(original_image,dtype=np.float64)
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if not distorted_image.shape == original_image.shape:
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raise ValueError("Input Imagees must has the same size")
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if len(distorted_image.shape) > 2:
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raise ValueError("Please input the images with 1 channel")
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kernal=gaussian_2d_kernel(window_size,gaussian_sigma)
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#求ux uy ux*uy ux^2 uy^2 sigma_x^2 sigma_y^2 sigma_xy等中间变量
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ux=correlation(distorted_image,kernal)
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uy=correlation(original_image,kernal)
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distorted_image_sqr=distorted_image**2
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original_image_sqr=original_image**2
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dis_mult_ori=distorted_image*original_image
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uxx=correlation(distorted_image_sqr,kernal)
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uyy=correlation(original_image_sqr,kernal)
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uxy=correlation(dis_mult_ori,kernal)
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ux_sqr=ux**2
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uy_sqr=uy**2
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uxuy=ux*uy
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sx_sqr=uxx-ux_sqr
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sy_sqr=uyy-uy_sqr
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sxy=uxy-uxuy
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C1=(K1*255)**2
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C2=(K2*255)**2
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#常用情况的SSIM
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if(alfa==1 and beta==1 and gama==1):
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ssim=(2*uxuy+C1)*(2*sxy+C2)/(ux_sqr+uy_sqr+C1)/(sx_sqr+sy_sqr+C2)
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return np.mean(ssim)
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#计算亮度相似性
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l=(2*uxuy+C1)/(ux_sqr+uy_sqr+C1)
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l=l**alfa
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#计算对比度相似性
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sxsy=np.sqrt(sx_sqr)*np.sqrt(sy_sqr)
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c=(2*sxsy+C2)/(sx_sqr+sy_sqr+C2)
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c=c**beta
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#计算结构相似性
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C3=0.5*C2
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s=(sxy+C3)/(sxsy+C3)
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s=s**gama
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ssim=l*c*s
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return np.mean(ssim)
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if __name__ == "__main__":
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start =time.clock()
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_--.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_02.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_03.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_04.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_05.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_06.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_07.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_08.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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ssim_number = ssim(cv2.cvtColor(cv2.imread("_01.jpg"), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread("_08.jpg"), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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end = time.clock()
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print('Running time: %s Seconds'%(end-start))
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img = cv2.imread("_--.jpg")
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print(img)
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'''
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images = ['_--.jpg','_01.jpg','_02.jpg','_03.jpg','_04.jpg','_05.jpg','_06.jpg','_07.jpg','_08.jpg','_09.jpg']
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start =time.clock()
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i = 0
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while i < len(images):
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j = 0
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while i+j < len(images):
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ssim_number = ssim(cv2.cvtColor(cv2.imread(images[i]), cv2.COLOR_BGR2GRAY),cv2.cvtColor(cv2.imread(images[i]), cv2.COLOR_BGR2GRAY))
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print(ssim_number)
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print("ssim of "+images[i]+","+images[j]+" is: "+str(ssim_number))
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j +=1
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i +=1
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end = time.clock()
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print('Running time: %s Seconds'%(end-start))
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'''
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