MATLAB: Drawing in the images

Question

Hi

I want to develop a procedure to remove some inpainted text from images, i.e. I have to estimate the inpainted pixels. I will do that with first an imputation step and then applying SVD (and perhaps later further improvements).

The imputations step just have to give an initial guess of the inpainted pixels. I thought of applying a gaussian filter to get estimates of the inpainted pixels, but I think this does not give good results.

Does somebody know another way to get good inital guesses, i.e. imputations?

Answer 1

I don't know how "imputation" applies to an image. What algorithm is that?

If the text was inpainted, and the inpainting was good, it will smear the surrounding through the text and it will basically disappear. It can be detected however - you can't get back the original text, but you can tell where the inpainting occurred. There are some forensic methods to detect such alterations in an image. And there are methods people use to try to prevent that - those methods are called anti-forensics. And there are even, believe it or not, forensic methods that try to detect when anti-forensic processed have been employed. These are called "counter anti-forensics". You might think I'm joking, but I'm not. Earlier this year I attended a few papers from a conference on it at a larger symposium.

I don't know how you'd use SVD. Why do you think you can? Have you seen a paper on that? Otherwise do a web search for "image forensics". The think is, I don't know how you can remove the inpainting. Once you detect where it was applied, what do you mean by "remove" it? Do you mean replace with black pixels, to make a guesstimate at what the original text might have looked like? That may or may not be possible depending on how far out the inpainting mask outline was.