Investigation of Project Moir: Interferometry Technique on Measuring Model Deformation

PMI(Project Moiré Interferometry) technique is a non-contact measurement technique based on projection system, video acquirement and image processing and analysis, which can measure continuity of model deformation and acquire the information of whole field of camera view. Compared with VMD(Videogrammetric Model Deformation), PMI can provide continue image of model deformation which brings more precise measurement of model deformation in full field of view and continue space. PMI is mostly used in test measurement of aero-elasticity investigation in wind tunnel. Projecting isometry grids and parallel on the surface of model in wind tunnel, PMI can apply image processing to determine the deformation of model surface. When instability of aero-elasticity and flutter appear, the data acquired by PMI can be adequately describe the relation between instability and model deformation. This paper presents the basic principle of PMI measurement system. At the same time it describes the key techniques such as projection device, image acquiring, image processing, calibration in detail, giving some preliminary tests results, predicting the development of PMI technique.