how can I increase the PSNR and Reduce the Standard deviation for the image?

I need to increase the PSNR and reduce the standard deviation for the image for comparing my method with the other method. How can I do that?

Answer 1

[Image Analyst]

Make your test image more like your original image. I don't know what you're doing to arrive at an image. Of course the easiest way is to just assign it

testImage = refImage;

We can't really say more because of a complete lack of context.