Quadratic (quadratic B-spline smoothing) works well with EWA

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NicolasRobidoux
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Quadratic (quadratic B-spline smoothing) works well with EWA

Post by NicolasRobidoux »

Preliminary testing suggests that the Quadratic filter (2nd degree B-spline with support [-1.5,1.5]) works well with EWA (when upsampling; downsampling, of course, is always another story):

Code: Select all

convert rose: -define filter:filter=Quadratic -distort Resize 3000% rose_quadratic.png
Of course, it's blurry and halo free.
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anthony
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Re: Quadratic (quadratic B-spline smoothing) works well with

Post by anthony »

It is also essentially a fit of the Gaussian filter :-) That explains why it has low aliasing effects, at the cost of blurry effects.
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NicolasRobidoux
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Re: Quadratic (quadratic B-spline smoothing) works well with

Post by NicolasRobidoux »

... or pushing the luma and chroma channels through EWA with BC-splines with different c: closer to Cubic for the chroma than for the luma, esp. when using chroma subsampling.
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