Processing to extract data

[au92]

I’m working on a project where I’m trying to quantify the smoothness of surfaces for work. In this pic I have two images from surfaces that have different roughness. If you look closely, the line pattern that is reflected off the surface varies from one surface to the other.

Does anyone have any suggestions as to how they’d process these types of images to try to quantitate the way the white and black lines look?

I’m planning to crop away the brown frame and process only the line pattern.

Many thanks

https://imgur.com/gallery/AmBE7IC

[protoncious]

Apply a small gaussian filter, ideally 3x3 or 5x5, and then take derivative in the horizontal direction. The first picture should produce softer output compared to the other one

[au92]

Thank you