POV-Ray : Newsgroups : povray.advanced-users : Skewness (long) : Re: Skewness (long) Server Time23 Jun 2024 06:38:39 EDT (-0400)
 Re: Skewness (long)
 From: Francois LE COAT Date: 5 Oct 2018 18:00:56 Message: <5bb7df18\$1@news.povray.org>
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Hi,

clipka writes:
> The matrix you've posted and described is for a 2D->2D projective
> transformation; that would be of no use in a 3D animation, as you can't

> just transform one output image into another, as depth is already lost
> at that point.

The projective transformation that I posted is useful in computer vision
to determine how the camera moves, the ego-motion, knowing the image
that is observed. If you can determine the motion of a planar surface
located in the image, this allows you to know the camera movements.

There's two simplifying hypothesis. Either the scene is static, and the
camera is moving. Or the scene moves, and the camera is static. If the
scene and camera are both moving, you have to segment static and
dynamic objects in the scene, in order to evaluate the camera motion.

I'm not really speaking of image synthesis, but rather computer vision.
The image synthesis with POV-Ray allows me to represent experimental
results. For instance in this video with the help of POV-Ray :

<http://hebergement.u-psud.fr/lecoat/camera_fixe.mp4>

I've determined the movements of the head, and represented it in VR ...

The goal of these researches is to measure as precisely as possible
the camera movements, knowing an image sequence contents. Knowing that,
you can elaborate trajectories, almost like a GPS would do it. You may
have heard about an algorithm called "Simultaneous Localization and
Mapping" (SLAM) helping robots to know their position and environment.

I've noticed the "Shear_Trans(X,Y,Z)" that will be useful in my work.