[Bf-vfx] Distortion and you

[Ton Roosendaal]

Hi Keir,

Sounds awesome! :)

The composite pipeline is under revision, it would be easiest for now  
to put the code clearly separated somewhere, and first work with a  
single (4 x float) buffer. Tiling & OpenCL support then is another  
topic for later.

Also check with Sergey for proper 'blender dna' design for a camera  
intrinsics data block. Can be part of the videoclip structure we have.

-Ton-

------------------------------------------------------------------------
Ton Roosendaal  Blender Foundation   ton at blender.org    www.blender.org
Blender Institute   Entrepotdok 57A  1018AD Amsterdam   The Netherlands

On 25 Jul, 2011, at 19:19, Keir Mierle wrote:

> One important remaining item for the blender motion tracker is  
> supporting camera distortion end-to-end. That means supporting  
> distortion in the camera solver (which means solving for the  
> distortion model during the 3D solve); this is in progress. The  
> other thing that has to be supported is both of the following:
> 	• Correcting distorted footage to make it perfectly rectilinear,  
> and compositing it with rendered footage, which is by default  
> perfectly rectilinear.
> 	• Rendering footage with distortion, either by distorting the  
> rendered frames (which means cropping the final video) or somehow  
> integrating distortion into the rendering, which I believe is  
> possible with cycles.
> Matthias is going to start enhancing the distortion code in libmv  
> and building warping nodes in blender's compositor which use the  
> camera models from libmv. It's critical that there is a distortion  
> node that uses the same distortion code as libmv, for future sanity  
> and quality of solutions. This does not preclude other distortion  
> nodes, just that there needs to be one that matches libmv.
>
> The distortion node should be able to take a "camera intrinsics"  
> data block from the solver. Currently the solver doesn't recover the  
> distortion terms, but this will change.
>
> The other issue is that we will probably support a couple of  
> different distortion models, but not at the start. We'll have to  
> keep this in mind when desiging things.
>
> The immediate plan is
> 	• Write a blender compositior node that runs forward distortion;  
> this will involve getting the machinery in place to pass tiles of  
> the image to libmv and back
> 	• Make undistortion in libmv fast
> 	• Extend blender's compositor node to also do undistortion with  
> libmv using the faster code
> 	• (maybe) add more camera models
> That's it.
>
> Keir
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