ULTRASONIC BIOMETRIC IMAGING SYSTEM AND METHOD FOR CONTROLLING THE ULTRASONIC BIOMETRIC IMAGING SYSTEM

摘要

The invention relates to an ultrasonic biometric imaging system (100) comprising: a cover structure (102) having a touch surface (104); a plurality of ultrasonic transducers arranged at a periphery of the touch surface; a plurality of mixed-signal integrated circuits configured to: AD-convert a received analog echo-signal to form a digital echo signal for each active ultrasonic transducer in the subset of ultrasonic transducers; perform local beamforming by introducing a first controllable delay to each digital echo signal to form a plurality of delayed echo signals; and sum the delayed echo signals to form an intermediate signal. The biometric imaging system further comprises a host processor connected to each of the plurality of mixed-signal integrated- circuits and configured to: receive intermediate signals from the of mixed- signal integrated-circuits; perform global beamforming by introducing a second controllable delay to each intermediate signal; and sum the delayed intermediate signals to form a final echo signal.