Transformations of a 3D Image Reconstruction Algorithm for Data Transfer and Storage Optimisation

When implementing a 3D image reconstruction algorithm on a DSP architecture, we find ourselves confronted with a large memory transfer overhead, reducing the possible speedup attainable on recent multi-media oriented architectures. This paper describes how the critical part of the algorithm is re-specified and aggressively transformed at the algorithm code level, to improve the data access locality of the multi-dimensional image signal, while preserving the input/output behaviour. Experiments show that a close to optimal reuse of the data in the foreground memory and registers is obtained, removing the data transfer and storage bottleneck and enabling real-time prototyping of the algorithm on a DSP architecture.