HISTOGRAM STRETCHING

% **** HISTOGRAM STRETCHING ****

a=imread('old imagelc.jpg');

aa=double(a);

[row col]=size(aa);

h=zeros(1,300);

rmax=(max(max(aa)));

rmin=(min(min(aa)));

slope=255/(rmax-rmin);

smin=0;

aa=aa+1;

for x=1:row

    for y=1:col

        c(x,y)=slope*(aa(x,y)-rmin)+smin;

    end

end

for x=1:row

    for y=1:col

   %if aa(x,y)==0

    %   aa(x,y)=1;

        t=aa(x,y);

        h(t)=h(t)+1;

    end

end

figure(1);

bar(h);

z=zeros(1,300);

for x=1:row

    for y=1:col

        %if aa(x,y)==0

         %   aa(x,y)=1;

        p=round(c(x,y));

        z(p)=z(p)+1;

    end

end

end

figure(2);

bar(z);

figure(3);

imshow(uint8(c));

figure(4);

imshow(uint8(aa));