Thank you both for the replies..the card board idea would certainly work, but would be a real hassle doing that for each skid.
The lighting I can't change because it took a long time to get just right to find the parts consistently. And I can't make the pattern more complicated on a lot of the parts because on some parts it's just 2 or 3 holes I can base it on.
I was wondering if there's instead a way to: whenever that error pops up simple turn off a flag and continue the program without erroring out. I though maybe that's what error recovery is for. But maybe there's no way to do this