New emerging embedded system platforms in the realm of highthroughput multimedia, imaging, and signal processing will consist of multiple microprocessors and reconfigurable components. One of the major problems is how to program these platforms in a systematic and automated way so as to satisfy the performance need of applications executed on these platforms. In this paper, we present our system design approach as an efficient solution to this programming problem. We show how for an application written in Matlab, a Kahn Process Network specification can automatically be derived and systematically mapped onto a target platform composed of a microprocessor and an FPGA. Furthermore, we illustrate how the mapping approach is applied on a real-life example, namely an M-JPEG encoder.