Nondestructive testing methods are used to inspect and test materials and components for discontinuities or differences in\nmechanical characteristics. Phased array signal processing techniques have been widely used in different applications, but less\nresearch has been conducted on contactless nondestructive testing with passive arrays. This paper presents an application of\nbeamforming techniques analysis using a passive synthetic microphone array to calculate the origin and intensity of sound\nwaves in the ultrasonic frequency range. Acoustic cameras operating in the audible frequency range are well known. In order to\nconduct measurements in higher frequencies, the arrangement of microphones in an array has to be taken into consideration.This\narrangement has a strong influence on the array properties, such as its beam pattern, its dynamics, and its susceptibility to spatial\naliasing. Based on simulations, optimized configurations with 16, 32, and 48 microphones and 20 cm diameter were implemented\nin real experiments to investigate the array resolution and localize ultrasonic sources at 75 kHz signal frequency.The results show\nthat development of an ultrasonic camera to localize ultrasonic sound sources is beneficial.
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