基于声呐历程累积图像的弱回波目标检测方法

针对浅海随机噪声与混响背景下蛙人等弱回波强度、慢速小目标的检测问题,提出一种基于声呐历程累积图像的目标检测方法。首先根据声呐图像时域、空域相关性,采用背景空时归一化处理技术,抑制声呐背景中的静态混响、突发性噪声等强回波干扰。声呐历程累积图像集成了多帧声呐图像的信息,目标回波亮点由于运动连续性形成亮线特征,利用该特征,采用Radon恒虚警率(Radon Constant False Alarm Rate,Radon-CFAR)检测声呐历程累积图像中的目标短时运动轨迹,能够检测到低信噪比的目标。分析了空时归一化处理和检测算法的性能,并通过海试数据验证了该算法的有效性,可以检测到低信噪比的蛙人目标回波。

Detection of weak echo targets based on sonar history accumulative image

For the detection of small low speed targets with weak echo intensity,such as frogman,under the background of random noise and reverberation in shallow sea,a target detection method based on sonar history accumulative image is proposed in this paper.First,according to the correlation of sonar images in time domain and spatial domain,the space-time normalization processing technique is used to suppress strong interference to the echo such as static reverberation and bursting noise in the sonar background.The sonar history accumulative image integrates the information of multiple frames of sonar images,and the echo highlights of target form bright line features due to moving continuity.By this feature,Radon constant false alarm rate(Radon-CFAR)method is used to detect the short-term moving trajectory of the target in the sonar history accumulative image,and the target with low signal-to-noise ratio can be detected.The performance of the space-time normalization processing technique and the detection algorithm are analyzed,and the feasibility of the detection algorithm is verified with sea trial data,which shows that the weak echo of low SNR from frogman target can be well detected.