how to assign weights to specific blocks of an image?

I want to perform face recongition using LBP feautres.In th eoriginal paper it is mentioned that some regions have mre information than the others such as eyes for facial recongition .And also they assigned it a weight(4) after dividing it into blocks also .My question is how to assign weight after dividing the image into blocks ?Should I just multiply the pixel values by 4?

But the region could become whit if I do that ( max value 255 for gray scale).Kindly help me out in this ....

One more question Should I apply weight first then lbp caluclation or lb first then apply weight????

[Image Analyst]

Wasn't it described in the paper? If not, then you should ask the authors to describe the missing parts so that you can replicate their work.