ptmviewer
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Summary	Dynamic image relighting viewer
Categories	None
License	GNU General Public License (GPL v. 2.0)
Owner(s)	cliffordlyon

HP Labs developed Polynomial Texture Mapping (PTM) as a way of increasing the photorealism of texture maps.  Coefficients of a biquadratic polynomial stored per texel are used to reconstruct the surface color under varying lighting conditions.  Like bump mapping, this allows the perception of surface deformations. However, the PTM method is image-based, and photographs of a surface under varying lighting conditions can be used to construct these maps. Unlike bump maps, Polynomial Texture Maps (PTMs) also capture variations due to surface self-shadowing and interreflections, which enhance realism.  Click on one of the sample images below to launch the Java viewer:

Our goal was to reproduce the functionality of the OpenGL viewer available from HP using Java.  Java allows users to access PTMs over the web.  We wanted to create a simple, intuitive, and user-friendly interface that allowed a user to get a sense of the power of the PTM technique in a few minutes using a modern web browser.  In addition, we have implemented some new features, such as using the recovered surface normals to perform sphere environment mapping.

The original PTM page is here:

• PTM Viewer
  

PTMs powered by Java can now be found around the web:

• Cultural Heritage Imaging
  
• Interactive Relighting of the Antikythera Mechanism
• Technique PTM at Congrégation du GSBernard
  
• PTM Project at National Gallery, London

The PTM Library developed in this project is used also by another browser specifically designed to handle PTMs with huge resolution.  This other viewer was developed by the Visual Computing Laboratory (ISTI-CNR)  of the Italian National Research Council, and is now part of this project.  For details on the display of high-resolution PTMs, see: PTMs for large objects.