Frontiers of Engineering Reports on Leading Edge Engineering from the 1996 NAE Symposium on Frontiers of Engineering (1997) / Chapter Skim
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Digitizing the Shape and Apperance of Three-Dimensional Objects
Digitizing the Shape and Apperance of Three-Dimensional Objects
Pages 37-46
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From page 37... ...
For small objects, applications may include product design; reverse engineering; museum archiving; and creation of models for visual simulation, movie making, videogames, and home shopping. For large objects, applications may include architectural preservation, engineering retrofits, virtual reality flythroughs, and recording of such cultural artifacts as sculptures, historic buildings, and archeological sites.
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From page 38... ...
By employing active sensing using structured light, we can independently measure geometry and reflectance, eliminating yet even more variables. Finally, by providing computer control over the operation of the scanner, we can acquire redundant data, improving the robustness (i.e., error tolerance)
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From page 39... ...
This takes several hours, but since our motion platform is partially automated, only a few minutes of human interaction is necessary. The result is a voxel array densely populated with signed distances.
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This figure illustrates the limited and fragmentary nature of the information available from a single range image. After digitizing and combining 58 such scans, we obtain a 2.6 million polygon mesh representing the entire statuette.
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which used a rapid prototyping technology called stereolithography. This process also takes several hours.
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From page 42... ...
In keeping with our goal of building inexpensive devices, we are designing a new generation of handheld gonioreflectometers that employ wide-angle optics, high-resolution sensor arrays, and commodity multimedia chips to compress the digitized reflections. Our goal is to build a device that is capable of quickly characterizing the reflectance of an unknown material to an accuracy sufficient to generate computer animations of objects covered with that material.
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From page 43... ...
The BRDF of a painted surface typically contains two components: a mirror-like but colorless reflection from the surface of the paint carrier and a diffuse but colored scattering of light from dye particles embedded in the carrier. We measured surface radiance using a color video camera, and then we used the known object and lighting geometry to correct for surface orientation, shadows, and specular highlights.
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shows a split view of the B-spline surfaces smooth shaded on the left with the polygon mesh on the right (a few displacement maps are given alongside their corresponding patches)
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From page 45... ...
We have already seen commercial applications of 3D digitization emerging at the professional and retailer level. For example, shoe and clothing manufacturers, with an eye on the custom-fit market, have begun installing range image scanners in their larger stores.
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From page 46... ...
1994. Zippered polygon meshes from range images.
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