WIP: Corner detection

[Robzz]

Implement Harris and Shi-Tomasi corner detectors, and some kind of corner refinement algorithm.

[codecov]

Codecov Report

Merging #5 into master will increase coverage by 1.76%.
The diff coverage is 72.29%.

@@            Coverage Diff             @@
##           master       #5      +/-   ##
==========================================
+ Coverage    89.9%   91.67%   +1.76%     
==========================================
  Files          12       12              
  Lines        1506     1921     +415     
==========================================
+ Hits         1354     1761     +407     
- Misses        152      160       +8

Impacted Files	Coverage Δ
src/lib.rs	100% <ø> (ø)	⬆️
src/core/neighborhood.rs	82.35% <ø> (ø)	⬆️
src/processing/histogram.rs	0% <ø> (ø)	⬆️
src/core/pixel_types.rs	99.18% <100%> (+0.93%)	⬆️
src/core/padding.rs	100% <100%> (ø)	⬆️
src/core/rect.rs	97.05% <100%> (ø)	⬆️
src/core/dynamic_image.rs	81.57% <14.28%> (+2.16%)	⬆️
src/io/png.rs	95.45% <53.84%> (+0.96%)	⬆️
src/io/tiff.rs	74.04% <58.06%> (+5.9%)	⬆️
src/io/mod.rs	96.91% <90%> (+0.01%)	⬆️
... and 6 more

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[vadixidav]

Is there a blocker here? Would you like a review? I can also rebase the branch on master after mine #11 is merged and fix any linting issues.

[Robzz]

I haven't worked on this crate for a little while, so as far as I remember, no, no real blockers, this just went to the back burner before I was finished. IIRC I had the Harris detector sort of working (though there may be a few issues left to resolve). I gave it a quick read and it looks like there's some stuff left to clean up. I was also trying to come up with a way to unit test that to gain a bit more confidence in that code, I guess I'll have to take a look at how (if?) other image libraries do it.

I'll try to finish it soon-ish after fixing the CI and merging #11. Reviews are always welcome, of course.

[vadixidav]

I am interested in making an orb detector + descriptor, but I think I will probably make that as a separate crate downstream of this repo. I will let you know how that goes and possibly make it easier during that process (by sending in some PRs) to allow you to refactor the actual detector stuff into its own crate as well.

[Robzz]

Okay. In that case I'll just remind you that this crate should be considered wildly unstable (I haven't even released it on crates.io yet) and that you might (i.e. probably will) encounter limitations I haven't thought of, weird APIs and/or outdated docs. I'm not saying it's impossible, but image and imageproc are probably safer bets right now. I didn't really expect anyone to use this yet 😸 But that should encourage me to get a usable release out the door when I'm less busy with other projects.

If you do work on it then absolutely please do let me know!