基于多光束照明的回波光场散斑抑制机理

Suppression mechanics of returning wave speckle with multibeams illumination

为了有效抑制激光照射目标表面所产生的散斑效应,提高激光主动成像图像质量,提出采用多光束照明技术,通过理论分析与仿真实验相结合的方式验证了多光束照明在抑制回波散斑效应方面的作用。首先,建立了多光束分光照明模型,理论分析了多光束照明对于完全散射叠加场和部分散射叠加场的散斑抑制原理。在此基础上,根据理论模型构建了仿真实验系统,采用不同能量分配的分光方式,对3种不同表面粗糙度的目标进行了单光束回波散斑对比度和多光束回波散斑对比度实验评估。实验结果表明:等能量4光束照明的回波散斑对比度仅为单光束对比度的1/2,与理论分析结果完全吻合,充分验证了多光束照明技术在回波光场散斑抑制方面的有效性。

In order to suppress the speckle effect of target surface induced by laser illumination,and to increase the image quality of laser active imaging,the multibeams illumination technology was adopted and its effect on rejection of returning wave speckle was investigated theoretically and experimentally.The splitting illumination model of multibeams was established.The speckle suppression principle of multibeams illumination in entire speckle superposed field and partly speckle superposed field was analyzed.On the basic of the principle and theory model,the simulation experiment system was set up,where the returning speckle contrast of single beam and multibeams illuminated on three different roughness targets with different splitting ways was evaluated by adjusting the energy distribution.The experiment result indicates that the contrast of homenergic four beam can be reduced to half of that of single beam,which complies to the theory analysis and proof the feasibility of speckle rejection using multibeams illumination.