A single photon array imaging lidar(SPAIL) based on the Geiger model has the characteristics of small size, high-sensitivity detection, high-resolution, non-scanning imaging and can realize the characteristics of undistorted three dimensional image of dynamic/static targets. However, In the case of high resolution, the instantaneous imaging field of view is small. To achieve high-precision recognition and tracking of targets in a large dynamic range, a high-precision servo and tracking system is required to completes the closed-loop tracking control of the target. A SPAIL platform incorporating a 64×64 array of Geiger-mode APD is constructed for validation and demonstration. The SPAIL is composed of three modules: scanning unit, optical transmitting and receiving unit, detection and processing unit. The scanning system uses a 26-bit high-precision encoder as the position loop detection element. The transmitting laser has a working wavelength of 1064.1nm, a working frequency of 10khz, a pulse width of 2ns.Subsequently, The optical receiving aperture of the laser is 60mm, and the line width of the narrowband filter is 0.1nm that filter out background noise interference. Multi-frame image correlation and dynamic threshold adjustment are used to complete target recognition, and the target tracking algorithm of Mean shift is used to extract the target. Under good weather conditions, during the dynamic scanning process of lidar, the target distinguished the 6km tower is completed respectively. SPAIL completed the real-time tracking and measurement of the 300m flying UAV (Unmanned Air Vehicle). In the future, the fusion of laser array image and visible light/infrared image information will be researched.
Phase information of coherent light is difficult to obtain directly through the Imaging optical system. At present, the more advanced method is to use coherent diffraction imaging method for phase recovery, but its imaging field of view is relatively small, and it is easy to appear the phenomenon of image reconstruction stagnation for objects with slightly complicated structure. Therefore, the effect of boundary conditions on coherent diffraction imaging method is studied in this paper. On the basis of the traditional coherent diffraction imaging method, this paper focuses on the transformation of the iterative conversion algorithm according to the different combination of the hybrid input and output method and the extrapolation method, and forms three new iterative conversion algorithms. The contrast experiment of coherent diffraction imaging method based on three new iterative transformation algorithms is designed by using interferometric test method. The experimental results show that the RMS value of the estimated phase deviation and ideal phase deviation is only 0.0096λ for the phase recovery method with single boundary condition, and the detection deviation RMS value is less than 0.0012λ for a phase recovery method with dual boundary conditions. This method has very important application value for phase recovery of coherent light.
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