Imaging sensor system using dispersed ultrasonic array

Imaging sensor system using dispersed ultrasonic array is described in this paper. Although ultrasonic elements are generally mounted on a plane or curved surface with separation shorter than half the wavelength of the ultrasonic wave for synthetic aperture systems, the elements can be distributed on any position and wide separations are acceptable for our system. Although delay-and-sum operations are used for synthetic aperture systems, delayed-and-multiplication operations were also used in our system to make the side lobe in the sensor directivity spectra small, and to obtain high resolution for the sensor array of the small number of ultrasonic elements. Furthermore, the intensities of the reflected wave differ based on the shape, material, direction, and distance to the object. Therefore, the signals are corrected by labeling the signals from each element. The characteristics of the system are studied by numerical simulation and experimentally. Since this system minimizes the possibilities of violation of privacy, it is suitable for shape measurement of three-dimensional objects in the residential areas.