Ultrasonic array imaging based on spatial interpolation

An ultrasonic array processing technique suitable for low cost imaging systems is presented. The technique is based on aperture synthesis approach through digital processing of array data acquired with a transmit subaperture and non-overlapping receive subapertures, each consisting of a small number of parallel active array elements. The number of beam lines scanning the image plane using a transmit-receive subaperture combination is chosen according to spatial sampling criteria of a single transmit-receive subaperture. A beam space interpolation scheme is employed to increase the number of beams for every low resolution subaperture image prior to their coherent summation resulting in a high resolution image. This approach reduces the number of firings for data acquisition, and therefore it allows one to achieve real-time imaging with very low susceptibility to motion artifacts. Its image quality is almost identical to that of the conventional phased array.