I want to go through a process of how I got...
I took a picture of the imprint with a webcam and started playing with the image in GIMP. After loading the image file, I created a new layer of the specific area so I could rotate it arbitrarily. Autocrop Layer. Autocrop Image.
Tried a few options from the Colors > Auto and settled for Stretch HSV. This would stretch the image contrast to cover the maximum possible range.