add xfeat+lighterglue and pairs from sequential

[pablovela5620]

Its been a little while since this PR got opened and I was hoping we could bring sequential matching!
#175

added exponential matching + loop closure using retrival based on this https://gitlab.ethz.ch/z-ricityslam/hloc_fork

I tested with South Building dataset since its sort of sequential (to make sure the loop closure worked).
Here is a video of the reconstruction + pairs generated. sequential matcher lead to a significant reduction in pairs created and lead to a good speedup in reconstruction!

Matching Type	Number of Pairs Generated	Reconstruction Time
Exhaustive Matching	8000	20 minutes
Vocabulary Tree Matching	6396	14 minutes
Sequential w/ Loop Closure	1543	9 minutes

sequential-reconstruction-2024-12-04_12.07.41.mp4

sequentail-matches-av1.mp4

I also included xfeat feature detector + lighterglue matcher from the great work over at https://github.com/verlab/accelerated_features

@sarlinpe let me know what I can do to help get this merged!

[robinlindh]

Hey, I have tried out the pairs_from_sequential, works very well. We use RGB data from mobile video captured at 10 FPS in a custom pipeline. Earlier we used pairs_from_poses (from some other PR on here earlier) and used 20 pairs. Now I use your pairs_from_sequential with:

    pairs_from_sequential.main(
        paths.sfm_pairs, references, None,
        window_size=6,
        quadratic_overlap=True,
        #use_loop_closure=False,
        #retrieval_path=None,
        #retrieval_interval=2,
        #num_loc=5
    )

The quadratic overlap with window size 6 gives us approximately the same range of nearby images as the 20 nearest poses, but using fewer pairs.
Running on a pretty big dataset we get a pretty big speed-up but still the same accuracy.
Haven't tried the retrieval-based loop closure yet but that will quite possibly improve our accuracy too so that looks very promising.

If anything, the window_size feels somewhat limiting currently as the same parameter controls both the number of pairs in direct sequence and the length of the furthest pair (growing quadratically). I just added some debug log on the first image to figure out what pair offsets I actually end up with as that would usually need to be handled with some care. In my case picking the window_size 6 gives a good sweet spot where the furthest pair is a few seconds away at our 10 FPS data. Would be nice to expose this a little bit more. Maybe a second parameter used for the number of quadratic overlap pairs, where the pairs are taken at +2, +4, +8 and so forth, starting from the END of the normal window size.

In any case, this is already very useful, so wanted to thank you for that!