Projective Transformations for Image Transition Animations

Transformation of image patches is a common requirement for 2D transition animations such as shape interpolation and image morphing. It is usually done by applying affine transformations to triangular patches. However, the affine transformation does not model the perspective transformation frequently found in images. Hence, such techniques can only produce approximate results and usually use an excessively large number of triangles to compensate for this shortcoming. This paper proposes the application of projective transformations on quadrilateral image patches as a solution to this problem. We address the issues of appropriate decomposition and interpolation of projective transformation matrices to produce a natural looking transition animation for a single quadrilateral as well as for shapes made up of multiple quadrilaterals.