Re: [Lcms-user] Question related to curve smoothing

[Pekka P. <pek...@ha...>]

On Mon, 24 Mar 2025 11:39:03 -0300
Leandro Ribeiro <lea...@ri...> wrote:

> Hello,
> 
> Based on [1], we've added the code to decompose a cmsHTRANSFORM into a
> shaper (3x1D LUT) + 3D LUT on Weston [2].
> 
> We want to smooth the shaper with cmsSmoothToneCurve(), but we don't know
> exactly how to choose the lambda parameter. In [1] we have: "lambda is a
> parameter by which we can trade smoothness of z against fit to data y". But
> would there be any drawback in using lambda == 0, i.e. allowing "full
> smoothness"?
> 
> Any feedback from your experience with that would be appreciated.
> 
> [1] https://www.littlecms.com/ASICprelinerization_CGIV08.pdf
> [2] https://gitlab.freedesktop.org/wayland/weston/-/merge_requests/1644
> 

Hi everyone,

we still don't know about this.

How do people choose the smoothing parameters for the shaper + 3D LUT
case?


Thanks,
pq