Fast Fourier Transform filtering for pattern removal. Some old photo prints have various regular patterns visble in the print. This is a texture that is embossed into the stock the image is printed on.
This is a problem that often comes when restoring old photos. The method used to remove the pattern is a frequency domain filter. In this case I used a Fast Fourier Transform plug-in for Photoshop. The one I use is only available for PC, the 2008 version by Alex Chirokov.
This is a funky old photo that needed restoration. Couldn't even start without getting rid of the embossed pattern.
You run the filter on a file in RGB mode. What you get is the strange image FIG 2. You bring up the red channel and it looks like Fig3yscale version of the photo with the pattern removed. You make this version a layer on top of the original and set the top layers to Color mode. This gives you a new color image without the embossed pattern.