Difference in pixel intensity regarding a black and white area in the image

I need to find the contrast behaviour of my camera. So i projected vertically divided gray and black image to screen and took photos. How to find difference in pixel intensity regarding a black and white area in the image?

My idea was, find histogram from black area and white area. Then substract. I am expecting a result which is attached.

I

Answer 1

[BhaTTa]

Hey @Akhilkrishna Panamkoottathil Ramakrishnan. please refer to below ML answer: https://www.mathworks.com/matlabcentral/answers/49744