Synthetic aperture image holography

Abstract

This paper describes the underwater imaging method of "Synthetic Aperture Image Holography" which has real-time imaging capability. This method utilizes image holography and computer synthetic aperture techniques. The imaging system consists of the acoustic lens, ultrasound receiving and transmitting arrays, and the computer. The diameter of the acoustic lens is smaller than the aperture of the transmitting array. By transmitting the ultrasound from the elements of the transmitting array one by one, the phase and amplitude of the lower resolution images (image holograms), focused by the acoustic lens, are detected by the receiving array. After obtaining all of the image holograms, the final image is calculated by synthesizing all of these image holograms in the computer. The results of one-dimensional underwater experiments are shown. The conceptual design of a real-time imaging system that is based on this method is also presented.