I'm trying to remove specular reflection from a ring light from my image. I want to remove specular reflection from both the test image and the flat image before performing flat-field correction. Here are the two images:
Test Image Flat / Background Image
The light and the camera are placed directly above the flat object (changing geometry is not feasible). My understanding is that the signal received by the camera is the sum of diffused color and the specular reflection. So to estimate the reflection component, I placed a black surface (same material as the original object) and captured the reflected component. The black surface was captured as follows:
However, when I try to subtract it from my image, the ring shaped area in both the images become darker, which implies that the black surface had a stronger specular reflection component than both the test image and the flat image. After subtraction of specular component, the image looks like this:
Can someone tell me why is that?
