说明：  多焦点图像融合 利用基于双边梯度的锐化标准 相当对应的论文是J. Tian, L. Chen, L. Ma and W. Yu, "Multi-focus image fusion using a bilateral gradient-based sharpness criterion,"
(This is a demo program of the paper J. Tian, L. Chen, L. Ma and W. Yu, "Multi-focus image fusion using a bilateral gradient-based sharpness criterion," Optics Communications, Vol. 284, Jan. 2011, pp. 80-87.)