查找表发数字图像处理示例程序。可以对图像灰度线性变换，显示直方图。

计算出最重要的256色，构造查找表，将24色图转变为256色图-Calculate the most important 256-color, structure look-up table, the 24-color map into a 256-color map

ENTITY maj IS PORT(a,b,c : IN BIT m : OUT BIT) END maj --Dataflow style architecture --Behavioural style architecture using a look-up table ARCHITECTURE using_table OF maj IS BEGIN PROCESS(a,b,c) CONSTANT lookuptable : BIT_VEC