how can I read and extract the 2 LSBs of every byte from the RGB image array ?

i want to read the 2 LSbs of every byte for exaple i want to read (00) from this byte (11111100) for the whole of the image

Answer 1

[yanqi liu]

clc; clear all; close all;
img = imread('cameraman.tif');
img2 = blockproc(img,[1 1],@sp);
figure; imshowpair(img,img2,'montage')

function y=sp(x)
% every byte 
x2 = dec2bin(x.data);
% 2 LSB of every byte
y=bin2dec(x2(end-1:end));
end

Answer 2

[Voss]

One way is to read the data as bytes (type uint8) like usual, then the 2 LSBs are the remainder after dividing by 4, e.g.:

b = uint8(0:255)

b = 1×256

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29

r = rem(b,4)

r = 1×256

0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1 2 3 0 1

s = dec2bin(r)

s = 256×2 char array
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'
    '00'
    '01'
    '10'
    '11'

a = s-'0'

a = 256×2

0 0 0 1 1 0 1 1 0 0 0 1 1 0 1 1 0 0 0 1