SYNTHETIC RECEIVE APERTURE IMAGING WITH PHASE CORRECTION FOR MOTION AND FOR TISSUE INHOMOGENEITIES .1. BASIC PRINCIPLES

A synthetic receive aperture (SRA) system could increase the resolution of a phased-array imaging system several-fold, by utilizing the available number of parallel receiver channels to address a larger number of transducer elements through a multiplexer system. Recent studies by ourselves and others indicate that transducers with a very large number of elements will improve the detectability of small or low contrast targets when adaptive focusing is used to compensate for the effects of acoustic velocity inhomogeneities in tissue. With the effectively increased transducer element count afforded by an SRA system, a 1-by-N phased array could be extended linearly to improve lateral resolution, or it could be split into an M-by-N array in order to improve resolution in the elevation dimension. Simulation results are presented that illustrate the lateral resolution achievable with several types of imaging systems synthetic receive aperture (SRA), synthetic focus (SF), and conventional phased array. Simulated images demonstrate the improvement in contrast resolution achievable using SRA. Also, experimental results are presented showing the improvement in beam width achieved by an experimental SRA system.