Morphing in stereo animation

There are several techniques that can be used to produce morphs of three-dimensional objects. The traditional solution is to apply 3D algorithms that transform the shape and attributes of one object into those of another. The problems in 3D morphing include avoiding self-intersections during the morph, specification of corresponding regions in the source and target objects and the imposition of geometric constraints an the objects. At first glance, the application of well understood 2D morphing techniques to stereo images would seem to be a reasonable and much simpler alternative to the production of 3D models and the application of 3D morphing to those models. While it is true that in certain cases the application of 2D linear morphing techniques to stereo images produces effective morphs, the use of this technique places very strict geometric constraints on the objects being morphed. When linear 2D morphing techniques are applied to stereo images where the parallax encoded in the images is of utmost importance, they linearly interpolate points between the source and target images which interpolates the parallax, also. We examine the ramifications of this limitation and discuss the geometric constraints under which stereo morphing is useful.