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The RADIANCE
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Synthetic Imaging System
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Greg Ward
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Lawrence Berkeley Laboratory
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1 Cyclotron Rd.
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Berkeley, CA 94720
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(415) 486-4757
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1. Introduction
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RADIANCE was developed as a research tool for predict-
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ing the distribution of visible radiation in illuminated
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spaces. It takes as input a three-dimensional geometric
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model of the physical environment, and produces a map of
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spectral radiance values as a color image. The technique of
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ray-tracing follows light backwards from the image plane to
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the source(s). Because it can produce realistic images from
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a simple description, RADIANCE has a wide range of applica-
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tions in graphics arts, lighting design, computer-aided
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engineering and architecture.
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The diagram in Figure 1 shows the flow between programs
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(boxes) and data (ovals). The central program is rpict,
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which produces a picture from a scene description. Rview is
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a variation of rpict that computes and displays images
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interactively.
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A scene description file lists the surfaces and materi-
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als that make up a specific environment. The current sur-
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face types are spheres, polygons, cones, and cylinders.
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They can be made from materials such as plastic, metal, and
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glass. Light sources can be distant disks as well as local
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spheres and polygons.
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From a three-dimensional scene description and a speci-
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fied view, rpict produces a two-dimensional image. A pic-
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ture file is a compressed binary representation of the pix-
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els in the image. This picture can be scaled in size and
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brightness, anti-aliased, and sent to a graphics output dev-
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ice.
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A header in each picture file lists the program(s) and
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parameters that produced it. This is useful for identifying
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a picture without having to display it. The information can
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