The imaging performance and efficiency are two important issues for the multireceiver synthetic aperture sonar (SAS). Back projection (bp) algorithm is characterised by the high performance and low efficiency. In this...
详细信息
The imaging performance and efficiency are two important issues for the multireceiver synthetic aperture sonar (SAS). Back projection (bp) algorithm is characterised by the high performance and low efficiency. In this study, the authors first recall the standard bp algorithm based on the interpolation for the multireceiver SAS. Then, two improved bpalgorithms based on the range Fourier transformation (FT) are presented. Considering the fact that the time delay in the time domain can be carried out by the phase shifting in the frequency domain, an FT shifting based bpalgorithm avoiding the interpolation error is presented. Although this method produces the focusing result with high performance, it is very time consuming. In order to improve the imaging efficiency without loss of imaging performance, the authors propose an oversampling-based bpalgorithm, which is based on the fact that the zero-padding in the frequency domain is equivalent to the interpolation in the time domain. After that, the computation complexity of three bpalgorithms is analysed in detail. Finally, simulations and real data are exploited to validate the presented methods.
The requirements of the correction of motion errors and high accurate registration are difficult to satisfy for the independence of the aperture paths in airborne repeat-track interferometry. Here, according to the pr...
详细信息
The requirements of the correction of motion errors and high accurate registration are difficult to satisfy for the independence of the aperture paths in airborne repeat-track interferometry. Here, according to the principle of the independence between the imaging scene and synthetic aperture radar (SAR) viewing geometry, the authors propose a new SAR imaging approach based on the idea of object orientation and back-projection (bp), where the complex motion compensation is effectively avoided and the image formation and registration are achieved simultaneously with high accuracy. In contrast to the standard bp algorithm, it greatly reduces the difficulty of registration brought by the irregular deviations. Moreover, it further successfully overcomes the influence introduced by the centre-beam approximation compared with frequency-domain algorithms. Experimental results both on simulated and actual SAR data are used to validate the proposed algorithm.
暂无评论