MATLAB RGB to Gray

function fenceng;img = imread('C:\Users\anyka001\Desktop\IMG_2696.JPG');[rows cols colors] = size(img);img_gray = zeros(rows,cols);img_gray = uint8(img_gray);  %把申请的空数组的double转换成uint8for x=1:rows    for y=1:cols        sum = 0;        for k=1:3            sum=sum+img(x,y,k)/3;        end        img_gray(x,y)=sum;    endendimshow(img_gray);[row col] = size(img_gray);img_bit =zeros(row,col);img_bit = uint8(img_bit);for bit=1:8    threshold = 2^bit;    for x=1:row        for y=1:col         if img_gray(x,y)< threshold && img_gray(x,y)>=(threshold/2)   %采用阈值判定的办法  卓个PIxel进行判断              img_bit(x,y) = img_gray(x,y);         else              img_bit(x,y) = 0;         end        end    end    figure,imshow(img_bit);end