说明：  图像评估指标FSIM，传统全参考图像质量衡量标准FSIM（feature similarity），仿效SSIM的计算构成，同样由两部分耦合的幂指数，FSIM由PC项和GM项耦合
(FSIM, the traditional full reference image quality measurement standard (FSIM), is composed of two parts of power index, FSIM is composed of PC term and GM term)