redshift

Actually I want to give ratings about the best tv screen. So by doing this, I will be able to know how uniform colors are on a particular screen. 

Do you have any idea about how can I do this?

What are you trying to ask sir? 

Hello.

I want to calculate standard deviation of color values of the pixels of a photo given below. I have seen this on some website and the standard deviation mentioned by that website of this pic is 4.207%.

They have mentioned steps that how they have done it which I am also attaching as a image. Problem is am not able to understand that how they have done it.

Please help me calculating this standard deviation and also how to process a image using Gaussian Blur.

Thank you.