function img = histEq(img)% 输入图像灰度、rgb图像都可以% 1 转灰度图像 2. 统计每一灰度级的数量 3. 累计灰度级 4. 归一化为累计概率 % 5. 当前灰度级的概率 P * 255 = 新映射的灰度级[width,height,channels] = size(img);if channels ==3img = rgb2gray(img); %rgb图像转成灰度end% 灰度级0-255，用hist数组% 数组下标1 开始hist=zeros(256,1);for j =1:heightfor i =1:widthgray_level = img(i,j); % 取出灰度值hist(gray_level+1) = hist(gray_level+1)+1; % 统计灰度值+1endend% 3. 累计灰度值hist_cumsum = cumsum(hist);% 4. 累计灰度概率hist_prob = hist_cumsum/(width*height);% 5. 遍历图片，映射新的灰度级for j =1:heightfor i =1:widthgray_level = img(i,j); % 取出灰度值t=hist_prob(gray_level+1)*255; % 映射img(i,j)=round(t); endend
