slo ~|•

When looking at the the hue plane after rgb2hsl conversion, the hue looks patchy/posterized and jumps around a lot. Is there some way address this to get smoother results or is that just the nature of hue? I suspect the latter but wanted to check.

When looking at the the hue plane after rgb2hsl conversion, the hue looks patchy/posterized and jumps around a lot. Is there some way addres

rgb2hsl-hue-plane-patchy

This issue appears as you want to extract the hue from compressed videos or images. An approach, common to many compression algorithms, is to pack togheter multiple pixels in structures called macroblocks to reduce data redundancy. The hue is usually uniform across a macroblock and, when watched in isolation, the hue plane looks jagged.

There's not much you can do to reconstruct a smoother (and coherent) hue plane. 

But depending on your final goal, you could try to blur it a little bit, or to add some dithering noise (or both).

If this doesn't work, try with uncompressed video/image formats

Hi Slo,
This issue appears as you want to extract the hue from compressed videos or images. An approach, common to many compression algorithms, is to pack togheter multiple pixels in structures called macroblocks to reduce data redundancy. The hue is usually uniform across a macroblock and, when watched in isolation, the hue plane looks jagged.
There's not much you can do to reconstruct a smoother (and coherent) hue plane. 
But depending on your final goal, you could try to blur it a little bit, or to add some dithering noise (or both). 

If this doesn't work, try with uncompressed video/image formats


Thanks for the response and suggestions. That makes a lot of sense and is helpful.

rgb2hsl, Hue plane patchy