图像灰度变换中的线性变换、对数变换、Gamma变换函数，不是利用matlab里面现成的函数实现，而是是利用数学公式计算得到，对于理解上述变换的实质有一定的价值
,Image gray-scale transformation of the linear transformation, logarithmic transformation, Gamma transform function, instead of using off-the-shelf function inside matlab implementation, but are calculated using mathematical formula for understanding the essence of the above-mentioned transformation must have the value of