better error message when BoardConfig wrong

[astraw]

Hi, we noticed that when providing a wrong board config (or when using the default board config when it is wrong), the error behavior does not lead one to immediate realize the problem:

thread 'main' panicked at src/util.rs:349:14:
called `Option::unwrap()` on a `None` value
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

(Digging deeper leads one quickly to a problem in optimizer, which gets intimidating quickly.)

I wonder if it would be straightforward to catch if the board configuration seems wrong and list this as a possible cause of the error.

[powei-lin]

It is difficult to tell whether the optimization failure is due to wrong board configuration, wrong model selection, wrong model initialization, or any other reason. The optimizer is just solving a general non-linear least square problem.

[powei-lin]

If you want to generate custom aprilgrid layout and config, try using the python script in https://github.com/powei-lin/aprilgrid-rs

[astraw]

Maybe a test that checks how many tags are expected and compares with how many are found in most images would be a decent heuristic to start.

Changing the error from a panic due to unwrapping a null to "The optimization failed. It is difficult to tell whether the optimization failure is due to wrong board configuration, wrong model selection, wrong model initialization, or any other reason. The optimizer is just solving a general non-linear least square problem." would be easier for a user to move forward with.