POV-Ray : Newsgroups : povray.advanced-users : Polynomial Texture Mapping Server Time: 18 Jun 2019 04:56:46 GMT
  Polynomial Texture Mapping (Message 1 to 2 of 2)  
From: Bald Eagle
Subject: Polynomial Texture Mapping
Date: 19 Jul 2017 20:15:00
Message: <web.596fbd55e768f79cc437ac910@news.povray.org>
or Reflectance Transformation Imaging (RTI)

http://www.hpl.hp.com/research/ptm/

"PTMs are typically produced with a digital camera by photographing an object
multiple times with lighting direction varying between images. Even a low-end
digital camera provides enough resolution to produce good PTMs, and almost any
light source can be used such as a light bulb, LED or flash.

Tools for viewing PTMs are downloadable below, as are tools for constructing
your own PTMs from images. Given a stack of images of an object under varying
lighting direction, one has collected samples of the objectís reflectance
function at each pixel. Independently for each pixel, the PTMfitter fits a low
order polynomial to those samples to produce a PTM. The PTMviewer simply
evaluates this polynomial in real time independently for each pixel to produce
an image.

This can be done at real-time rates on even low-end computers because of the
simplicity of the polynomial, allowing interactive control of lighting
direction. In addition, once the reflectance functions are represented in this
manner, they can be transformed to make the surface detail existing on the
object more apparent. We call this method reflectance transformation, ...."

http://www.hpl.hp.com/research/ptm/se.html
http://www.hpl.hp.com/research/ptm/papers/ptm.pdf


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From: Bald Eagle
Subject: Re: Polynomial Texture Mapping
Date: 28 Jul 2017 16:15:01
Message: <web.597b62c65399d421c437ac910@news.povray.org>
http://studylib.net/doc/12947938/polynomial-texture-maps-tom-malzbender-dan-gelb

has an interesting yet simple overview of the what and how

http://palentier.blogspot.com/2011/09/

presents an interesting way of utilizing this with 3d models to create a better
lighting / shading method.


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