激光主动成像图像的多帧后处理算法研究

在确定激光器的发散角度、脉冲峰值功率、接收光学系统的参数以及确定激光器和接收光学系统的几何配置后,激光主动成像系统要想得到更远距离更高分辨率的微弱目标的图像,就只受微弱目标的探测成像及处理技术的制约,因为在较长的距离和有限的激光能量下,不可能立刻照明整个目标场景,接收成像端CCD上每个像素接收到的光照度也不可能达到相当的水平。为了在特定的脉冲激光能量下增加成像系统的成像距离,同时减轻大气扰动对成像分辨率的影响,研究了一种独特的图像处理算法,用激光多脉冲来获取整个目标场景的图像,采用辐射量来确定每次曝光时间内最大景物照明区域,这种独特的多帧后处理算法,可以在大气扰动和连续散粒噪声影响下,得到比传统连续照明方式更高分辨率的图像。

Multiframe postprocessing algorithm of laser active imaging images

After fixing on the divergent angle, peak power of laser pulse, parameters of received optical system and the geometrical configuration between laser and received optical system, a faint target image of longer range with higher resolution obtained by active imaging system is constrained by imaging and processing technologies. With longer range and limited laser energy, it is impossible to illuminate the entire scene at once, and the illuminance obtained by each receiver pixel of CCD can not achieve an adequate level. In order to increase the imaging range of imaging system with given per-pulse laser energy, and to reduce atmospheric turbulence effects on image resolution, multi pulses may be employed to obtain image data over the whole scene and radiometric conceptions are used to establish the maximum scene illumination region during each exposure. A unique multiframe postprocessing technique is investigated in this paper. It is shown that in the presence of atmospheric turbulence and coherent speckle effects, this approach can produce superior results to conventional scene flood illumination.