Remove dublicated SIFT-Dectector instance in feature matching

[kielnino]

It seems to me that the SIFT detector is instantiated, but then not used, because the object is created again in the following while loop. This merge request removes the unnecessary code.
I have also made the missing parameters of the OpenCV-Sift implementation configurable.

[facebook-github-bot]

@fabianschenk has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator.

[kielnino]

In the old version, the detector was created unnecessarily and then overwritten later, but the feature descriptor was not recreated in the loop. It was only a copy of the original and then deleted detector object, but is now also copied again each time in the loop. I wonder if the current behavior might be creating some overhead?

[kielnino]

Maybe we should move the line descriptor = detector to run only once after the while-Loop, conditioned on the context.OPENCVXX flags?

[kielnino]

@fabianschenk Do I need to adjust something to make the FB-internal tests pass?

And in addition do you have any thoughts about this?

Maybe we should move the line descriptor = detector to run only once after the while-Loop, conditioned on the context.OPENCVXX flags?

[facebook-github-bot]

@fabianschenk merged this pull request in b18e638.