utils.py 文件源码

def batch_ssim(dbatch):
    im1,im2=np.split(dbatch,2)
    imgsize=im1.shape[1]*im1.shape[2]
    avg1=im1.mean((1,2),keepdims=1)
    avg2=im2.mean((1,2),keepdims=1)
    std1=im1.std((1,2),ddof=1)
    std2=im2.std((1,2),ddof=1)
    cov=((im1-avg1)*(im2-avg2)).mean((1,2))*imgsize/(imgsize-1)
    avg1=np.squeeze(avg1)
    avg2=np.squeeze(avg2)
    k1=0.01
    k2=0.03
    c1=(k1*255)**2
    c2=(k2*255)**2
    c3=c2/2
    return np.mean((2*avg1*avg2+c1)*2*(cov+c3)/(avg1**2+avg2**2+c1)/(std1**2+std2**2+c2))