Shape Recognition and Position Measurement of an Object Using an Ultrasonic Sensor Array

Shape recognition of a transparent object is usually difficult to perform by image processing techniques, because the major portion of the light projected onto an object passes through the object. As a result, the object cannot gain the light intensity required for image processing. Ultrasonic sensors are often utilised in situations where such optical sensors cannot be used. Moreover, systems using ultrasonic sensors are simpler and cheaper than systems using other types of sensors. Although the ultrasonic method has such advantages, results from the conventional ultrasonic method do not always have high measuring resolution, due to the wide directional pattern of the sensing. Up to now, the application of the ultrasonic method has been limited compared to the optical method.