Reflectance Analysis and Synthesis using the Tapered Kaleidoscope

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In 2003, the Principal Investigator and his collaborators introduced a new technique for measuring the appearance of a textured object as it is viewed or illuminated from different directions. The technique, which requires no mechanical movement and is very easy to calibrate, is based on use of a tapered kaleidoscope: a tapered hollow tube of polygonal cross-section, whose inner walls are lined with front-surface mirrors. This arrangement is used to simulate the effect of a large array of cameras and projectors, all pointing toward the target object from different directions. This technology promises to improve measurement and display in many areas by grounding computer generated imagery more thoroughly in real-world data and by making the means of capture more readily available to a greater number of researchers. The technology also has worthy forensic uses, such as bullet and fingerprint identification, and early detection of skin melanomas, as well as materials measurements for simulation. There is also enormous potential benefit from proposed earlier work on using the kaleidoscope principle to create a lightfield transducer, which has potential for creating a new type of three dimensional display exhibiting fundamentally improved angular characteristics.Because this approach to data capture introduces no mechanical error, it promises to enable a new field of inquiry into questions that rely on precisely calibrated measurement of multi-view, multi-illuminated, and multi-spectral optical characteristics. Research tasks include mathematical modeling and analysis as well as practical lab-bench experimentation and data collection in the following areas: Capturing eight dimensional surface BSSRDF, capturing full lightfield for 3D objects, capturing full spectrum of lightfield with tunablewavelength filters, real time multi-view structured light depth scanning, increasing angular resolution through combined use of multiple cameras and narrow taper angles, making effective use of image fragments, synthesis from sparse and non-rectangularsamples, and experiments toward extreme wide-angle lightfieldtransducers.