I came across this fascinating website that takes a very close look at a CMOS sensor. I want to make sure that I understand the optical black (OB) region, and the active pixel array. I marked these two regions in the following picture. I was wondering what the region in the edge (marked with question mark) is? Is that non-microlensed pixels mentioned in the article? If yes, then what is the purpose of non-microlensed pixels?