How to find the contrast value of an image?

I have to extract features of a retinal image out of which contrast of the image is one feature. Is there any inbuilt function to find the contrast value of a grayscale image? I dont find any inbuilt function or corresponding code.

Answer 1

[KSSV]

Refer here:

https://in.mathworks.com/matlabcentral/answers/231214-how-to-find-the-contrast-of-a-image-in-matlab

https://in.mathworks.com/matlabcentral/answers/81133-how-to-calculate-contrast-per-pixel-cpp-of-an-image

[Vishalini Ram]

Sir, I have referred the first link which says image_contrast = max(grayImage(:)) - min(grayImage(:)); But in my work, i have another feature where i have to find difference between maximum intensity and minimum intensity. I have done that already. Now i cant do the same operation in the name of contrast of image. I dont find the other link useful too. Could you help me further?

[Syed Zenith Rhyhan]

How this code can be worked?

Please give me the source code?

[Image Analyst]

This is the source code given in the answer:

image_contrast = max(grayImage(:)) - min(grayImage(:));

Did you overlook it? grayImage should be replaced with the name of your image variable of course.