How to calculate PSNR of a double sized image

While executing there is a error on command window how to remove this error:

%%psnr and mse
err = immse(im, K);
fprintf('\n The mean-squared error is %0.4f\n', err);
[peaksnr, snr] = psnr(im2double(im, K));
fprintf('\n The Peak-SNR value is %0.4f', peaksnr);
fprintf('\n The SNR value is %0.4f \n', snr);

Errors while executig the code :

??? Undefined function or method 'immse' for input arguments of type 'double'.

Error in ==> UNTITLED>pushbutton2_Callback at 316
err = immse(im, K);

Answer 1

[Walter Roberson]

immse() is for calculating Mean Squared Error (MSE), but you want to calculate PSNR.

immse() was added to the Image Processing Toolbox as of R2014b.

psnr() was added to the Image Processing Toolbox as of R2014a.

[ayushi]

ok thank you sir

[Spandan Tiwari]

Slightly aside, but relevant - there's another image similarity metric computing in the Image Processing Toolbox called ssim() for Structural Similarity Index.

Answer 2

[Image Analyst]

I have a manual way to do it, before they introduced those built-in functions. It's attached.

[Balasubramanian Durairajan]

wonderful