Implementation of a wide-angle lens distortion correction algorithm on the cell broadband engine

Wide-angle lenses are often used in scientific or virtual reality applications to enlarge the field of view of a conventional camera. Wide-angle lens distortion correction is an image warping application which transforms the distorted images back to the natural-looking, central perspective space. This application is characterized by a non-linear streaming memory access pattern that makes main memory bandwidth a key performance limiter. This paper presents the implementation, optimization and evaluation of a wide-angle lens distortion correction algorithm on the Cell Broadband Engine. Cell is a heterogeneous multi-core processor that has been architected to accelerate applications with large degree of thread- and data-level parallelism. We alleviate the `memory wall' inefficiencies by applying source level optimizations such as tiling to better utilize the on-chip memory of the SPE, and maximize data reuse within a frame of pixel data. Using these transformations on the Cell processor, we are able to achieve a 7.27x speedup compared to a Core2 Duo processor, and enable potential applications such as real-time correction for video teleconferencing using cameras with wide-angle lenses. To the best of our knowledge, this is the first paper to describe the mapping and optimization of an image warping application to the Cell BE architecture.