零交差を用いた濃淡画像からの光線方向および3次元形状推定法

概要

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In this paper, we propose a new estimation method of 3D shape of an object from its shading information, under the assumption that the direction and strength of an illuminant and the surface albado are unknown. In most well-known estimation methods for 3D shape, the direction of the illuminant is assumed to be known. In most practical cases, however, the illluminant direction is unknown. For these cases, a new theory was proposed where the illuminant direction and 3D shape are simultaneously estimated from shading information. This theory can be applied to an object with simple surface such as sphere and ellipsoid. In this paper, it is shown that this method can not be applied to an object whose surface has concave parts. We propose a new theory which has not such a drawback. In this theory the illuminant direction is roughly estimated from shading information, and then the exact illuminant direction and 3D shape are successively estimated using the rough illuminant direction and constraints on zero-crossings of shading. We show example of estimation by the proposed algorithm. The result of the example supports efficiency of the proposed theory.
東海大学の論文