[tgarv]

I wonder how much easier it would be if you narrow down the likely set of pieces for each square. There are obviously some positions for some pieces that are invalid (bishop on the wrong colored square), but there are probably a lot of other positions that are so uncommon that they could be discounted.

[levesque]

What would make it easier IMHO is to make it a top-down version only. Take a photo from the top, then the program breaks down the board into 8x8 squares, feeds each square into a classification algorithm that you will train on a bunch of hand labeled images. Fine tune the model as you gather more data.

[dmurray]

The pieces look more similar from the top, though. With bad enough contrast everything is just a circle. So you need some kind of angle.

[codetrotter]

> With bad enough contrast everything is just a circle.

Yes but does real world photos ever have that poor contrast? IMO, top down photo is worth exploring.

[rtkwe]

Probably not much. How many are actually impossible if you factor in pawn promotion though? The only one that comes to mind immediately for any individual piece is pawns on their own first row and a board without two kings.