[Elphel-support] mono video output postprocessing

[Gergely Debreczeni]

Dear Andrey !

 Thanks for these pointers. We will try your advices, however the problem with
JP4 is that it is too big. We would need a minimum of 10 fps @ half resolution,
which we found is not feasible for this camera.

Anyway, will so how far we can get.
Cheers,
Gergely
 
________________________________________
De : support-list <support-list at support.elphel.com>
Envoyé : jeudi 1 août 2013 06:14
À : Gergely Debreczeni; Elphel List
Objet : Re: [Elphel-support] mono video output postprocessing

---- On Wed, 31 Jul 2013 02:58:16 -0700 Gergely Debreczeni<gergely.debreczeni at kishonti.net> wrote ----

 >   Hello,
 >
 >  Now we use our stereo camera in mono mode, so the resulted
 >  8bit grayscale video's pixels corresponds to the color value of the CCD
 >  in
 >
 >   G G
 >   R B
 >

Gergely, it is actually
GR
BG
greens are diagonal.

 >  layout - if I'm right.
 >  I'm just wondering: Is there any easy way (preferably in Linux)
 >  to convert this format into a video of half size, half width where one pixel
 >  corresponds to some function (intensity/average/etc..) of the above four pixel ?

It will not give you much - the center of R and B colors is shifted, so to do that correctly you need de-Bayer or demosaic of your data. And I strongly recommend you using JP4, not JPEG if you want raw Bayer from the camera.
Additionally all the lenses have aberrations, including chromatic, and blue color resolution is significantly worse than for green (or even red) - it is the same as for the human eyes. So if you want to easy way to process data for 3d reconstruction - forget about blue and red - just use (and calibrate distortions) green only.

 >
 >  I was looking for some filter in ffmpeg, but found none which could perform
 >  this task.

Yes, it is so because there is no easy and useful way to do that.

Andrey