A modified iterative conjugate gradient technique is developed and applied to limited-view interferometric tomography for reconstructing flow fields of simple structure. The approach is also effective in dealing with significant noise present in the data. From a computer simulation of experiments, a multipath interferometric system is built, from which multidirectional projection interferograms can be captured in real time for fast transient phenomena. The system is employed to measure an asymmetric temperature field. The three-dimensional field is then reconstructed with the developed experimental and computational techniques. The results are satisfactory when compared with thermocouple measurements.

Computational and interferometric system for real-time limited-view tomography of flow fields

This paper presents an interferometer which has been developed for real time quantitative refractive index measurements at video rate. A theoretical accuracy analysis of the measured phase distribution is presented for linearly stratified refractive index profiles. The interferometer is characterized experimentally. Therefore, phase distributions generated by a tilted mirror are measured by the real time interferometer and a common interferometer which contains a piezoelectric transducer.

Design of a real-time Michelson interferometer for quantitative refractive index profile measurements

Algorithms for extracting shock wave fronts from interferograms of a flow field and for registering time-series shock waves are proposed. Based on these, application software is developed on a PC-Vision 100 image-processing system. As application examples, interferograms of a primary high-explosive flow field and a real, solid rocket muzzle flow field are processed. The results indicate that the propagation velocity of the shock wave can be easily calculated with this method.

Yi Ge

Papers

Automatic extraction and registration of shock wave fronts from series interferograms of a flow field.