Research On Rotation And Scale Invariance Of Targets With Cluttered Background In Optical Correlation Detection

Detection and recognition of targets with cluttered background by real-time joint transform correlator is always the front technology in this field. Compared with conventional matched filter, joint transform correlator has many advantages such as real-time processing speed, high positioning accuracy and the flexibility of computer process, which can satisfy the requirement of detection and recognition of targets with cluttered background. This technique has been applied in navigation systems of missiles and rockets for its high recognition rate.Theoretical and experimental research is developed on detection and recognition of targets with cluttered background by real-time joint transform correlator in this paper. Research result shows when observation perspective or observation distance changes, angular or scale distion appears, which is produced by target image relative to the template image. While conventional joint transform correlator is very sensitive to various distortions, which effect the recognition rate to a great extent. Several algorithms and their advantages and disadvantages are researched in this paper to solve the recognition problem of distortion invariant targets, in which polar-in transform method is researched deeply and the experimental results are given. After analysis and comparision, Maximum average correlation height(MACH) filter is adopted to realize filtering in power spectrum plane.Computer programs of MACH for image processing are compiled. To make it applied in joint transform correlator, the spectrum filtering is changed to power spectrum filtering in the program. Simulation experiments and optical experiments of optical correlation recognition are conducted. The results show the intensity of correlation peaks are strengthened and distortion invariant target detection and recognition in cluttered background is realized after MACH filtering.As to the recognition and tracking of moving targets with cluttered background, dynamic template technology is proposed, which is to take the instantaneous state of moving targets as the template. Optical experimental research is conducted by dynamic template technology combined with threshold processing in the input image plane. Research shows the recognition and tracking of moving targets with cluttered background can be realized.