I am getting closer to the solution, however have a bigger problem than expected.

As the camera is pointing at the projection surface, I have the classical video feedback effect. As a result, the corrected image is getting bigger and bigger, and I loose more of the image,

than the fish eye correction was made with the [curve3d].

how could I move the image after gemframebuffer and move back with the offset of the pix_snap?

Or what for the offset is made?

Is there any method to avoid the video feedback in pix_buffer?

Looking forward to any brilliant idea :)

Popesz

On Wed, Jul 17, 2019 at 10:00 PM Christof Ressi <christof.ressi@gmx.at> wrote:

Personally, I would always prefer a fragment shader over fiddling with curve3d in GEM :-) This is probably what you want: https://www.geeks3d.com/20140213/glsl-shader-library-fish-eye-and-dome-and-barrel-distortion-post-processing-filters/5/

It might need some modification depending on the kind of texture and GLSL version your using.

Christof

Gesendet: Mittwoch, 17. Juli 2019 um 21:27 Uhr
Von: "Csaba Láng" <langcsaba@gmail.com>
An: pd-list@lists.iem.at
Betreff: Re: [PD] fish eye camera distortion correction

Thanks for the ideas.

Luckily I will snap the pix just once a second or two. Hope the processor can handle it.

Which correction is easier, curve3d or the shader?

On Wed, 17 Jul 2019 at 21:04, Jack <jack@rybn.org> wrote:

Sure, use a framebuffer with [gemframebuffer] to capture offscreen your
scene.
The problem is to send back your texture produce by [gemframebuffer] in
pix_ domain to use [pix_movement] and [pix_multiblob], fortunately there
is [pix_snap] for this (this process is quite slow, it depends on your
hardware).
Look at :
Help => Gem => examples => 04.pix/ => 26.framebuffer_readback.pd
to see how to use it.

A note, instead off [curve3d] it is also possible to use shaders (on
fragment) to do the correction of the lens distorsion.
++

Jack

Le 17/07/2019 à 20:36, Csaba Láng a écrit :
> Looks good, but now a bigger problem came up.
>
> My aim is to correct the fish eye distortion for pix_movement and
> pix_multiblob analyses.
> Which means first I have to make the curve3d correction and then use
> those pixels in pix_multiblob.
> Is it possible?
>
> On Wed, Jul 17, 2019 at 8:16 PM Johnny Mauser
> <joson.android@googlemail.com <mailto:joson.android@googlemail.com>> wrote:
>
> Maybe gems [curve3d]?
>
> Csaba Láng <langcsaba@gmail.com <mailto:langcsaba@gmail.com>>
> schrieb am Mi., 17. Juli 2019, 20:10:
>
> Hi list,
> is there an easy way to correct fish eye camera image distortion?
> I think if a vortex kind of tool.
> Best,
> Popesz
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