基于事件相机的空间目标事件流降噪算法  

Denoising algorithm for space target event streams based on event camera

作　　者：周晓丽 贝超 张楠 辛星 孙祚明 Zhou Xiaoli;Bei Chao;Zhang Nan;Xin Xing;Sun Zuoming(CASIC Space Engineering Development Co.,Ltd.,Beijing 100854,China)

机构地区：[1]航天科工空间工程发展有限公司,北京100854

出　　处：《红外与激光工程》2023年第9期318-327,共10页Infrared and Laser Engineering

摘　　要：针对事件相机探测空间目标时输出大量噪声的问题,提出基于事件相机的空间目标事件流降噪算法。首先,考虑到事件流的时空相关性和异步特性,提出基于邻域密度的时空相关性事件流滤波器(Neighborhood Density-based Spatiotemporal Event Filter,NDSEF),以帧的形式在时间维度累积事件并计算邻域密度,达到降噪的目的。然后,提出基于NDSEF的级联滤波器,通过增加像素维度窗口累积实现算法的高度优化,达到细化滤波的目的。最后,在公共数据集和仿真数据集实验中实现滤波算法的高速与高泛化能力,该滤波器在信噪比和噪声比两项指标上均超过了经典滤波器,事件处理速度可达10μs,对于多目标空间事件流可以有效处理噪声事件。实验结果表明该滤波器在低信噪比空间场景中保证了降噪算法的准确性和时效性。Objective Event camera can capture the real-time changes of the scene.It only outputs brightness changes of the pixel level and asynchronous event stream with microsecond resolution.It has the advantages of high event resolution,high dynamic range,low delay and low bandwidth.Its application in the space target detection has gradually attracted the attention of researchers.At present,there are following challenges in the application of event camera.On the one hand,event camera is sensitive to environmental changes and outputs a lot of noise.On the other hand,the remote detection of space target will output the point-target event stream,resulting in a low signal-to-noise ratio,which demands higher requirements for the processing algorithm of space event stream.Therefore,denoising algorithm for space target event streams is very important for data preprocessing.For this purpose,denoising algorithm based on event camera is proposed.Methods For event stream data of space targets,this paper proposes the Neighborhood Density-based Spatiotemporal Event Filter(NDSEF),which is based on the neighborhood density,to reduce the local spatial neighborhood noise of each time neighborhood by compressing the image frame.Combined with the characteristics of space target trajectory,a circular local sliding window is set to adjust the selection range of spatial neighborhood,and noise filtering based on spatial information is realized(Fig.3).On this basis,this paper proposes a cascade filter based on NDSEF for different scenes and targets in the space environment.Through multiple stages of increasing the cumulative window of pixel dimensions,the multi-dimensional combination filter can gradually refine the event data and obtain the best noise reduction performance.Results and Discussions This paper demonstrates the high-speed and high-generalization ability of the denoising algorithm in the public datasets and the simulation datasets.The scene information of the experimental datasets is shown(Tab.1-2),including three single-target sce

关 键 词：事件相机 空间探测 时空相关性 降噪 

分 类 号：V528[航空宇航科学与技术—人机与环境工程]