Xingyu Pan and imageLaure Tougne have published a paper describing their database of digits extracted from scans of modern coins.
The database of 3000+ images itself cannot be directly downloaded. They explain here that you may request it from them.
The paper is good! The databases discussed are
- 606 digit images manually cropped from high-resolution photographs of well-conserved coins
- 1,200 digit images automatically extracted from a subset of a PCGS database containing coins in different states of preservation
- 1,200 digit images manually extracted from the same coin photographs as above
Although the new dataset only contains digits from modern coins the authors discuss the literature of recognition of ancient coin lettering. There are as yet no public databases of images of the digit or letters extracted from images of ancient coins.