Remove direct downscaling from input image to top level of every octave #178
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added 2 commits
October 21, 2025 08:20
The other levels existed only for direct downscaling.
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This is a little piece of PR #159 |
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Description
PopSift has several modes to create the Gaussian pyramid. These were written to increase the potential parallelism of PopSift and explore trade-offs between speed and quality.
This PR removes the DirectDownscaling approach, which generated the top level of every octave directly
from the upscaled input image. In practice, the quality drop of this implementation was too large to be practical.
Features list
This PR does not add any features. It removes features.
The direct downscaling method has been removed.
Implementation remarks
Removed the config param ScalingMode (always use default).
Removed code to create the top level of every octave directly from the input image, direct downscaling is now only used for the input image.
Use horiz_from_input_image exclusively for octave 0, remove octave parameter.
Reduced the Gaussian filter table h_gauss.dd to a single instance. This table contained Gaussian filters considering the initial blur for every octave's top level.