I've been building a similar piece of software but with vibe coding. It's to the point that I'm using gauge blocks to measure the precise scoring ring dimensions and then using various warping techniques to get the photo to map precisely. In a weekend I've been able to get it to sub pixel accuracy.

For comment reading edification, there are already electronic scoring targets for shooting.[0]

They use wave detection from each corner - either air/sound or via the target backing - to triangulate and with modern electronics can be quite accurate.

It's nice from an audience point of view to be able to see the results of each shot almost immediately. Kinda like watching snooker championships.

This approach is novel however and has other pros and cons.

[0] https://en.wikipedia.org/wiki/Electronic_scoring_system

Scoring is based on the outermost ring, rather than the innermost ring?

Huh. I'd have expected it to be based on the center, but I guess the goal is "it must be entirely within this ring to count" rather than just "I hit this ring".

My USPSA rank is public: I'm terrible with pistols. I haven't shot in competition for over a decade. This is the kind of project that tickles a couple of my nerves and might get me back to the range.

Wasn't sure what to expect when I clicked this link.

This ... Is beautiful

>> .22 bullet is 0.22" across (duh)

Um... No. An american 22 can be very slightly smaller. American-invented calibers are measured to the depth of the grooves in a rifled barrel. The rest of the world measures to the flat parts between the grooves. So no, it is not obvious how wide a bullet is.

And beware the plural. If someone (usually a salty navy person) says that a gun is "50 calibers" he means something completely different than a "50 caliber".

https://en.wikipedia.org/wiki/Caliber

Of all the things one can automate in this whole journey - he chose the ring counting on the shooting range? I don't get it.

I totally see the programming challenge there, but it's in no substantial way making the journey any easier. Any somewhat working human brain can count this quite quickly and then move on with other things.

Really, I don't get it.