[sift] Remove unreachable code #180
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This piece of now unreachable code was a replicating buggy OpenCV behaviour that existed in 2016. Its case was no reachable callable with any valid command line or library parameter.
simogasp
approved these changes
Oct 24, 2025
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Description
This removes one of two alternatives for downscaling from the 3rd last layer of an octave to the first layer of the next octave. There were two alternatives:
(1) pick only the even pixels from the even rows (this version is retained)
(2) perform a linear interpolation between a square of 4 pixels (this version is removed)
The second approach was now unreachable code that replicated buggy OpenCV behaviour that existed in 2016.
The real bug was not in the downscaling according to (2), it was that everything else in the code was indexed as if (1) had been used.
In PopSift, this case has not been reachable with any valid command line or library parameter for a long time because it led to errors in feature position computations.
Features list