该matlab代码主要用于计算图像的边缘强度，信息熵，灰度均值，标准差(均方差MSE)，均方根误差，峰值信噪比（psnr），空间频率(sf)，图像清晰度，互信息(mi)，结构相似性(ssim)，交叉熵(cross entropy)，相对标准差。- calculate the　uation average gradient, edge strength, information entropy, gray are Value, standard deviation (mean square error MSE), root mean square error, peak signal to noise ratio (psnr), spatial frequency (sf), image clarity, mutual information (mi), structure Similarity (ssim), cross-entropy (cross entropy), the relative standard deviation.