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Computer Science Honours – Rhodes University 28 July 2004. Obtaining the Bidirectional Texture Reflectance of Human Skin by means of a Kaleidoscope. Jude Radloff Research Project Presentation Supervised by Shaun Bangay and Ad é le Lobb.
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Computer Science Honours – Rhodes University 28 July 2004 Obtaining the Bidirectional Texture Reflectance of Human Skin by means of a Kaleidoscope Jude Radloff Research Project Presentation Supervised by Shaun Bangay and Adéle Lobb. Part of the Virtual Reality Special Interests Group (VRSIG).
Today’s Presentation • Objective • Background to reflectance measurement • Introduction to the Kaleidoscope technique • Investigation of various configurations – simulated • Practical implementation • Next step in research process • Questions
Objective :Increased realism of simulated real-world surfaces. Ultimately human skin, being a highly complex surface.Currently focusing on preparation. Bidirectional Texture Function (BTF) describes how INCOMING light is REFLECTED OFF a surface, and how this VARIES over the surface BTF ( θi, Φi, θo, Φo, u, v )
Han and Perlin, 2003 Proposed a novel technique in measuring reflectance by means of a kaleidoscope Kaleidoscope’s reflective properties allow a sample to be viewed from a variety of directions - without the need for mechanical movement. Potentially: • More economical (time / finance) • More accurate, because of less calibration • Simpler • Easier to use
Investigation of configurations- by simulation Considerations : • Field of View • Levels of Reflection • Number of Sides • Angle of Taper • Alternative Configurations • Non-tapered • Additional mirror(s) beneath sample
Taper causes interreflections, which results in a virtual sphere
In a non-tapered configuration, the result is a tiled sample image
Experimental configuration: Tapered cylinder – each level of reflection containing a single distorted image
Recent development :Physical implementation of selected configurations based on our findings in the AFRIGRAPH paper On display today : • 3-sided non-tapered kaleidoscope • 4-sided tapered kaleidoscope • 4-sided tapered kaleidoscope with extended reflective base – this novel configuration is expected to result in an even richer BTF measurement
Next Step… • Set up camera and projector as described in the Han and Perlin paper (2003). • Build up BTF database of view-illumination pair digital images. ILLUMINATION VIEW