Abstract
A circular holographic sonar utilizing an inverse problem solution is proposed in this paper. First, a parallel image reconstruction algorithm is developed, which has block-circulant characteristics. Second, through the several experiments, we show this holographic sonar can reconstruct an exact image with high resolution. Finally, a circular systolic array processor executing the image reconstruction algorithm is proposed.
This holographic sonar is based on three techniques, circular holography, inverse problem solution and systolic array processing. It has following features: (1) A circular array construction enables to obtain a complete azimuthal holographic data and to reconstruct an exact azimuthal image. (2) An inverse problem solution produces the much higher resolution than one which a conventional back propagation produces. (3) An isoazimuthal image reconstruction procedure enables to design a circular systolic array processor, which can reconstruct an image in real-time.
The estimated time for image reconstruction of 65, 536 points (256 sectors×256 points) is about 0.4s using this circular systolic array processor. From this estimation, this holographic sonar has an effectiveness for a robotic sensor system.
