Conference Paper

A Dual Light Stage.

DOI: 10.2312/EGWR/EGSR05/091-098 Conference: Proceedings of the Eurographics Symposium on Rendering Techniques, Konstanz, Germany, June 29 - July 1, 2005
Source: DBLP

ABSTRACT We present a technique for capturing high-resolution 4D reflectance fields using the reciprocity property of light transport. In our technique we place the object inside a diffuse spherical shell and scan a laser across its surface. For each incident ray, the object scatters a pattern of light onto the inner surface of the sphere, and we photograph the resulting radiance from the sphere's interior using a camera with a fisheye lens. Because of reciprocity, the image of the inside of the sphere corresponds to the reflectance function of the surface point illuminated by the laser, that is, the color that point would appear to a camera along the laser ray when the object is lit from each direction on the surface of the sphere. The measured reflectance functions allow the object to be photorealistically rendered from the laser's viewpoint under arbitrary directional illumination conditions. Since each captured re- flectance function is a high-resolution image, our data reproduces sharp specular reflections and self-shadowing more accurately than previous approaches. We demonstrate our technique by scanning objects with a wide range of reflectance properties and show accurate renderings of the objects under novel illumination conditions.

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    ABSTRACT: We present a novel acquisition device to capture high resolution 4D re- flectance fields of real scenes. The device consists of a concave hemispher- ical surface coated with a rough specular paint and a digital video projector with afish-eye lens positioned near the center of the hemisphere. The scene is placed near the projector, also near the center, and photographed from a fixed vantage point. The projector projects a high-resolution image of incident illu- mination which is reflected by the rough hemispherical surface to become the illumination on the scene. We demonstrate the utility of this device by cap- turing a high resolution hemispherical reflectance field of a specular object which would be difficult to capture using previous acquisition techniques.


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