contrast.m

to flip image in matlab

function contrast(x,flag)
global IMG
data=double(IMG);
[m n r]=size(data);
x=power(150,x/100);
  for j=1:n 
     for i=1:m
       for k=1:r
         data(i,j,k)=round(((data(i,j,1)-128)*x)+128);
         if (data(i,j,k)>255)
            data(i,j,k)=255;
          end;
         if (data(i,j,k)<0)
             data(i,j,k)=0;
          end;
       end;
     end;
  end;
res=uint8(data);
if flag==0
imshow(res)
else
IMG=res;
imshow(IMG)
end    
end