How to calculate PSNR of binary image

Please ,tell me the PSNR equation for binary image,whose pixel values are just 0 or 1 .

Thanks in advance.

Answer 1

[Pratik]

Hi,

'psnr' function can be used to calculate the value given the original and reconstructed image.

Please refer to the following documentation of 'psnr' function for more information:

www.mathworks.com/help/images/ref/psnr.html

[DGM]

IPT psnr() does not accept logical inputs.

Admittedly, all logical images are "binarized", but not all "binarized" images are logical; however, in most contexts, it's reasonable to assume that binary image handling within MATLAB is done using logical arrays.

They could always be cast as double or any other class, but bear in mind that they must be cast and scaled.

inpict = imread('cameraman.tif');
a = inpict>127;
b = inpict>128;

% this works
psnr(im2double(a),im2double(b)) % cast and scaled

ans = 22.2430

% this is identical
psnr(im2uint8(a),im2uint8(b)) % cast and scaled

ans = 22.2430

% but if the inputs are not scaled to suit their class
% then the measure becomes class-dependent.
psnr(uint8(a),uint8(b)) % cast, but not scaled

ans = 70.3738

psnr(uint16(a),uint16(b)) % cast, but not scaled

ans = 118.5725