采用反向投影算法进行宽带合成孔径声纳数据处理与图像重建

Wide-band synthetic aperture sonar data processing and image reconstruction with back projection algorithm

文中提出了宽带合成孔径声纳(SyntheticapertureSonar,简称SAS)成像的反向投影算法(backprojection,简称BP)。该算法是在时间 空间域中对合成孔径线列阵中各个阵元接收回波的所有频率分量进行相干求和,以充分利用合成孔径上所有回波的能量,从而得到理想的SAS图像。同时,文章中分析了BP算法实现过程中拖尾(tail)现象的产生机理,对BP重建图像进行了斜坡滤波处理。并对载频为15kHz、带宽为20kHz的SAS系统进行了仿真,结果验证了这种算法的有效性。

Imaging by high-resolution synthetic aperture sonar (SAS) is studied to detect buried targets. Based on characteristics of sound propagation in water and sediment, a SAS data processing and image reconstruction technique using a back projection (BP) algorithm with a low frequency and wideband signal is analyzed in this paper. In this algorithm, in order to make full use of the energy received at the synthetic aperture elements, all the sonar echoes with respect to every element in the synthetic aperture array are coherently summed. Since shadowing and tail phenomena occur due to the 1/r-tail effect during the implementation of BP, image processing is performed using a ramp filter resulting in a clear reduction of the tail and shadowing effect and improvement in the azimuth resolution. Computer simulation is presented to verify the effectiveness of the data processing and image reconstruction approach for a 15kHz-SAS imaging system with a 20kHz bandwidth.