How I Can read 3 MSBs in RGB image

e.g the Bit in image is 250 =11111010

I want to red the 3 bits of Most Significit bit =111

How I can do that

Answer 1

[DGM]

Depends what you want the output to be. It might be simple for scalar inputs:

% assume uint8
pixel = uint8(250);

% using dec2bin() to get a character vector
binarypixel = dec2bin(pixel)

binarypixel = '11111010'

msb3 = binarypixel(1:3)

msb3 = '111'

% using bitget() to get a logical vector
msb3_2 = bitget(pixel,8:-1:6)

msb3_2 = 1×3

1 1 1

... but array inputs will need to be handled differently.

% if you want to get bit planes of an array, you can use bitget()
bit8 = bitget(pixel,8)

bit8 = uint8 1

bit7 = bitget(pixel,7)

bit7 = uint8 1

bit6 = bitget(pixel,6)

bit6 = uint8 1

% or just use basic math
bit8 = mod(pixel,256)>=128

bit8 = logical
   1

bit7 = mod(pixel,128)>=64

bit7 = logical
   1

bit6 = mod(pixel,64)>=32

bit6 = logical
   1

Pay attention to the output class and scaling here. Bitget() is returning a uint8() output, while the latter is returning actual logical outputs.