Obtaining Surface Orientation from Texels under Perspective Projection

A new method to obtain surface orientation of textural plane under perspective projection is described. Firstly, we derive a 2-D Affine transformation which approximates the distortion of texel patterns under perspective projection. Then we present a method to obtain the vanishing line of the plane from the area of texels in the picture. It can obtain a vanishing point from an arbitrary pair of texels; when n texels exist, C2, vanishing points can be obtained. An algorithm to solve the 2-D Affine matrix between two patterns is also presented. It reinforces the method to be applicable to a texture which is constituted from more than two kinds of texel patterns. Experiments are performed by using artificially generated textures.