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%計算圖像對比度
%中心像素灰度值與周圍8近鄰像素灰度值之差的平方之和，除以以上之差的個數。
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clear;
clc;
format?long;
[filenamepathname]?=?uigetfile（{‘*.jpg;*.bmp;*.png‘}‘打開待測對比度的圖像‘）;
if?filename?==?0
????return;
end
pic?=?imread（[pathnamefilename]）;
[mnl]?=?size（pic）;%求原始圖像的行數m和列數n
if?l>=2
????pic?=?rgb2gray（pic）;?