How to compare similarity between two images?

Can i get the code to compare the similarity of two images of same size. function of SSIM is not working in my matlab can i get the code of it.plz help

[pekka lunga]

this may help http://www.codeforge.com/read/149073/compareimages.m__html

Answer 1

[Image Analyst]

Why is it not working? I've attached a demo for computing PSNR that does not use the built-in psnr(). It's used as an alternate to ssim -- it was used a lot before ssim came along.

[SHALU SINGH]

i don't need psnr to cal. similarity, i need internal cal. of ssim through that i can compare the images

[Image Analyst]

Then get the code - it's in the lastest (and probably some older) version of MATLAB, or program it up yourself from the definition.

[SHALU SINGH]

i am using matlab2013a. is this function does't work in this or i need new version of matlab.