[FFmpeg-devel] [PATCH v2] avfilter/vf_edgedetect: properly implement double_threshold()

[Andriy Gelman]

On Mon, 29. Jun 09:26, Valery Kot wrote:
> On Sun, Jun 28, 2020 at 12:03 AM Andriy Gelman <andriy.gelman at gmail.com> wrote:
> >
> > lgtm. I saw a small improvement when testing.
> >
> > Would be nice to allow weak edges that become strong to trigger neighboring weak
> > edges in the future.
> 
> Thanks for the comment.
> 
> You are right, ideally double_threshold should be recursive (seed from
> each "high" peak and spread over "low" peaks). But then potentially we
> may end up with width*height/2 recursion depth, which may lead to
> stack overflow. So probably some recursion limit is needed, and hence
> suboptimal solution.
> 
> Or iterative approach, running through the complete image again and
> again checking if "low" peaks are touching already selected edge
> pixels. Stop when no new pixels can be added to the edge. Better, but
> still potentially width*height/2 iterations with width*height
> operations each, completely killing performance.
> 
> Maybe later I'll try to implement it in a generic way, but this is out
> of scope for this patch.
> 
> Regards,
> 
> Valery Kot

Any objections if I apply this patch? 

-- 
Andriy