A real-time, synthetic-aperture, digital acoustic imaging system

We present recent results obtained with a 32-element real-time synthetic aperture acoustic imaging system. The system, which was described at last year’s Acoustic Imaging Conference, has been developed in two main directions. First, a comprehensive testing program has enabled us to diagnose and correct a number of sources of electronic error, and this, coupled with the addition of high quality grey scale display systems, has resulted in greatly improved image quality. Second, in recognizing the need for quantitative as well as qualitative interpretation of NDE images, we have developed a communication channel between the imaging system and a mini-computer. This facility allows us not only to process experimental data collected from the imaging system with greater sophistication than is possible using the real-time hardware alone but also enables us to obtain images synthesized from theoretical models generated in the computer and rapidly reconstructed in the imaging system. This is an extremely useful facility since it is possible to compare the experimental performance of the system directly with what would be expected theoretically.