pkg load image

clear
clc

I = imread('peppers.bmp');

I8 = bitget(I, 8);
I7 = bitget(I, 7);
I6 = bitget(I, 6);
I5 = bitget(I, 5);
I4 = bitget(I, 4);
I3 = bitget(I, 3);
I2 = bitget(I, 2);
I1 = bitget(I, 1);

Ir = uint8(2*I1 + 1*I2 + 8*I3 + 4*I4 + 32*I5 + 16*I6 + 128*I7 + 64*I8);

myPSNR = psnr(Ir, I, 255);

subplot(2,4,1), imshow(I, [0 255]), title('Original')
subplot(2,4,2), imshow(Ir, [0 255]), title('Switched bit planes')