Generalized image warping using enhanced lookup tables
Peter R. Mattson, Donglok Kim, Yongmin Kim · International Journal of Imaging Systems and Technology · 1998
Image warping includes a wide variety of algorithms used in the spatial transformation of images. Warping typically involves a geometric transformation governed by a set of polynomial equations followed by some form of interpolation. When the geometric transformation does not change from one image to the next, or a more generalized warp is desired, a spatial lookup table (LUT) composed of precalculated inverse (or forward) mapping coordinates has been used instead of performing the same geometric transformation on every image. This article presents an algorithm that takes the LUT approach one step further. It uses an enhanced LUT (ELUT) that incorporates precomputed data transfer and interpolation information. Once computed, it speeds up processing by making data transfers more efficient and eliminating the need for the pixel address and interpolation coefficient calculations. This article also describes the implementation of ELUT-based image warping on the high-performance TMS320C80 Multimedia Video Processor (MVP). To produce an interesting and difficult generalized warp on a 512 × 512 8-bit gray-scale and 32-bit color image, it takes only 15.1 and 32.4 ms, respectively. © 1998 John Wiley & Sons, Inc. Int J Imaging Syst Technol 9: 475–483, 1998