基于事件相机的合成孔径成像  

Event Camera Based Synthetic Aperture Imaging

作　　者：余磊[1] 廖伟 周游龙 杨文[1] 夏桂松 YU Lei;LIAO Wei;ZHOU You-Long;YANG Wen;XIA Gui-Song(School of Electronic Information,Wuhan University,Wuhan 430072;School of Computer Science,Wuhan University,Wuhan 430072)

机构地区：[1]武汉大学电子信息学院,武汉430072 [2]武汉大学计算机学院,武汉430072

出　　处：《自动化学报》2023年第7期1393-1406,共14页Acta Automatica Sinica

基　　金：国家自然科学基金(62271345,61871297);中央高校基本科研业务费专项资金(2042020kf0019)资助。

摘　　要：合成孔径成像(Synthetic aperture imaging,SAI)通过多角度获取目标信息来等效大孔径和小景深相机成像.因此,该技术可以虚化遮挡物,实现对被遮挡目标的成像.然而,在密集遮挡和极端光照条件下,由于遮挡物的密集干扰和相机本身较低的动态范围,基于传统相机的合成孔径成像(SAI with conventional cameras,SAI-C)无法有效地对被遮挡目标进行成像.利用事件相机低延时、高动态的特性,本文提出基于事件相机的合成孔径成像方法.事件相机产生异步事件数据,具有极低的延时,能够以连续视角观测场景,从而消除密集干扰的影响.而事件相机的高动态范围使其能够有效处理极端光照条件下的成像问题.通过分析场景亮度变化与事件相机输出的事件点之间的关系,从对焦后事件点重建出被遮挡目标,实现基于事件相机的合成孔径成像.实验结果表明,所提出方法与传统方法相比,在密集遮挡条件下重建图像的对比度、清晰度、峰值信噪比(Peak signal-to-noise ratio,PSNR)和结构相似性(Structural similarity index measure,SSIM)指数均有较大提升.同时,在极端光照条件下,所提出方法能有效解决过曝/欠曝问题,重建出清晰的被遮挡目标图像.The technique of the synthetic aperture imaging(SAI)can reconstruct the occluded objects by blurring out the occlusions through multi-view exposures,which is equivalent to imaging with the large aperture and low depth of field.However,due to the very dense disturbances of occlusions and low dynamic range of traditional cameras,it is hard to effectively reconstruct the occluded objects by SAI with conventional cameras(SAI-C)under dense occlusions and extreme light conditions.To address these problems,we propose a new SAI method based on event cameras which can produce asynchronous events with extremely low latency and high dynamic range.Thus,it can eliminate the dense disturbances of occlusions by measuring with almost continuous views and tackle the problem of imaging with extreme light conditions.Particularly,the occlusions can be blurred out and the occluded objects can be reconstructed from the focused events followed by relating the brightness change to the generated events.The experimental results demonstrate that the proposed method can greatly improve the contrast and sharpness of the reconstructed images under dense occlusion conditions comparing to the SAI-C.Quantitative comparisons of peak signal-to-noise ration(PSNR)and structural similarity index measure(SSIM)also illustrate the superiority of the proposed method.On the other hand,under extreme light conditions,the proposed method can effectively solve the over/under exposure problem and reconstruct the occluded objects clearly.

关 键 词：事件相机 合成孔径成像 遮挡物去除 图像重建 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]