Design Of Flow Field Velocity Measurement System Based On DSP

Particle Image Velocity (PIV) is a flow field velocity measurement technology based on image processing developed since 1980' s and is characterized in instantaneous and non-contact measurement on whole flow field without interference, so it is very important to the study of complex flow field velocity measurement.After analysis of PIV algorithms, a flow field velocity measurement system based on DSP is designed in this paper. The system is composed of TMS320DM642, camera and LCD. It is integrated in image capture, data process and result display, thus implementing the flow field velocity measurement.The PIV algorithm analysis, system hardware and software design are introduced in the thesis. As to algorithm, PIV technologies are discussed, the influence of interrogation window size affecting calculation results in cross-correlation algorithm is analyzed and an algorithm is proposed which can ensure a suitable interrogation window size adaptively based on the cross correlation function value, thus providing the rationality of choosing the suitable interrogation window. In hardware design, the digital signal processor TMS320DM642 of TI Corporation is chosen as the kernel part of the system and its functions video processing modules are analyzed. In software development, the real time operation system DSP/BIOS programming is analyzed, the original video image processing model is discussed and improved, some algorithms are implemented based on TMS320DM642 in Code Composer Studio such as image capture and display algorithm, PIV algorithm and raster graphic algorithm etc. Besides that, the difficulties and problems occurred in the project design are also illustrated.The experiment data show that the algorithm developed in this paper improves the system precision, the system implements the functions needed in the flow field velocity measurement and the verification expriment proves the correctness of the measurement result. Thus these researches can provide the basis for the future system instrumentation.