Okay, the way is very simple, but requires a bit of work and patience. You can get any picture like those: Textures for 3D, graphic design and Photoshop!
In photoshop create a layer with one of the RGB colors. Paste the piece of the picture with the damaged wood as a mask for the layer and adjust brightness or contrast with curves, so you clamp it to almost black and white. This way you will separate wood from paint from the original picture.
I will try to explain it better with images.
Cheers.