DIGITAL HOLOGRAPHIC PARTICLE IMAGE VELOCIMETRY: 3D VELOCITY FIELD EXTRACTION USING CORRELATION

摘要

Digital holography is used to extend 2D Particle Image Velocimetry to volumic field measurements thanks to the use of correlation. The flow seeded with particles is analyzed from two successive holograms recorded by in-line holography directly on a numerical sensor. The holograms are then processed in order to extract the 3D displacements. The principle of the algorithm is to represent a pattern (i.e., the particles enclosed in a given 3D interrogation cell) by means of a binary plane mask. The localization of the pattern in each of the two holograms is computed by cross-correlation of the mask in the reconstructed spaces. The originality of the approach lies in the process of localization of a set of particles. The feasibility is validated by tests carried out in controlled conditions.