How to recover data hidden in an image from a photo of a printed copy?

Question

Image processing

It is required to encode a hidden message in an image (in my case, these are several rectangular areas defined for a given image). Then, the image is printed and after that the hidden areas are recognized through the camera shot/several shots.
I am using OpenCV. Tried to move in the direction of such algorithms as LSB (the simplest), DFT/DCT/DWT, but so far without result. It is not possible to use recognition algorithms, since hidden rectangles can be anything. QR codes are also not suitable, as the hidden information must be invisible.
How difficult and is it even possible to implement such logic? Those. I plan to use not just steganography, but the restoration of a noisy and deformed image, because the camera additionally gives geometric and color distortions. If this is possible to implement, then what approaches and algorithms would you recommend?

Answer 1

If you want to read on this topic in Russian - look at the works of this author