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.