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Illumination of image-based objects

✍ Scribed by Wong, Tien-Tsin ;Heng, Pheng-Ann ;Or, Siu-Hang ;Ng, Wai-Yin

Publisher
John Wiley and Sons
Year
1998
Tongue
English
Weight
207 KB
Volume
9
Category
Article
ISSN
1049-8907

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✦ Synopsis

A new data representation of image-based objects is presented. With this representation, the user can change the illumination as well as the viewpoint of an image-based scene. Physically correct imagery can be generated without knowing any geometrical information (e.g. depth or surface normal) of the scene. By treating each pixel on the image plane as a surface element, we can measure its apparent BRDF (bidirectional reflectance distribution function) by collecting information in the sampled images. These BRDFs allow us to calculate the correct pixel colour under a new illumination set-up by fitting the intensity, direction and number of the light sources. We demonstrate that the proposed representation allows re-rendering of the scene illuminated by different types of light sources. Moreover, two compression schemes, spherical harmonics and discrete cosine transform, are proposed to compress the huge amount of tabular BRDF data.

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