Detection Technology Of Large Scale Hybrid Distortion Target

Optical correlator has the programmable, controllable characteristics of electrical systems and the advantages of high speed, parallelism in optical systems. It also can quickly identify and position the target, so it has been widely used in the field of target detection and recognition. The most commonly optical correlators are Vander Lugt correlator and the joint transform correlator. As a consequence, the technique has been applied in face recognition, medicine tumor recognition, optical fiber detection and navigation systems of missiles and rockets for its high recognition rate.In this paper, we demonstrate the detection technology of large scale hybrid distortion target. We first introduce the background and the significance of our work. Then the theory and the technology of optical correlation detection and recognition are introduced. However, in practical, the traditional optical correlator is very sensitive to the distortion, which is caused by the change of target's size, direction,due to the change of the observation distance and angle. To solve the problem, many algorithms have been proposed, such as Polar-Merlin transform, Fractional Fourier transform, Circular Harmonic Function and Synthetic Discriminate Function.We analyze the Polar-Merlin transform and put forward the Area-Polar coordinate transform algorithm, which can better solve the problem of large scale mixed distortion. The algorithm we used is the relationship between the area mapping and the similar objects. By this, we first realize the scale invariant, then we realize the rotation invariant by Polar transform algorithm. Finally we acquired the edge of joint image processed by wavelet transform. Using this method, we can extract the edge features with low image noise. Besides, the proposed algorithm can not only improve the correlation peak effectively, but also realize the detection and recognition of large scale hybrid distortion. The results of simulation and optical experiments show that the Area-Polar coordinate transformation can realize large scale hybrid distortion of target detection and recognition.