SKiPPER: A Skeleton-Based Parallel Programming Environment for Real-Time Image Processing Applications

Abstract

This paper presents SKiPPER, a programming environment dedicated to the fast prototyping of parallel vision algorithms on MIMD- DM platforms. SKiPPER is based upon the concept of algorithmic skele- tons, i.e. higher order program constructs encapsulating recurring forms of parallel computations and hiding their low-level implementation de- tails. Each skeleton is given an architecture-independent functional (but executable) specification and a portable implementation as a generic pro- cess template. The source program is a purely functional specification of the algorithm in which all parallelism is made explicit by means of com- posing instances of selected skeletons, each instance taking as parameters the application specific sequential functions written in C. SKiPPER compiles this specification down to a process graph in which nodes cor- respond to sequential functions and/or skeleton control processes and edges to communications. This graph is then mapped onto the target topology using a third-party CAD software (SynDEx). The result is a dead-lock free, optimized (but still portable) distributed executive, which SKiPPER finally turns into executable code for the target platform. The initial specification, written in ML language, can also be executed on any sequential platform to check the correctness of the parallel algorithm. The applicability of SKiPPER concepts and tools has been demonstrated by parallelising several realistic real-time vision applications both on a multi-DSP platform and a network of workstations. It is here illustrated with a real-time vehicle detection and tracking application.