This paper presents (in french) a methodology for rapid prototyping of VLSI circuits dedicated to real-time image processing. The algorithm, written in a functional language, is firstly validated in the target environment of the circuit (real time and real life scenes) on a custom emulator: the Data-Flow Functional Computer. The adequation between the description of algorithms and the emulator's architecture yields important advantages in terms of ease of emulation, quality of validation and integrability.