Time delay estimation method and system for use in ultrasound imaging

An ultrasound system for estimating beamforming time delay, the ultrasound system comprising:

• a transducer array having a set of array elements disposed in a pattern, each of the elements being separately operable to produce a pulse of ultrasound energy during a transmission mode and to produce an echo signal in response to vibratory energy impinging an imaging object during a receive mode;
• a transmitter coupled to the transducer array and being operable during the transmission mode to apply a separate transmit signal pulse with a respective transmitter time delay to each of the array elements such that a directed transmit beam is produced;
• a receiver coupled to the transducer array and being operable during the receive mode to sample the echo signal produced by each of the array elements as the vibratory energy impinges the imaging object to generate a corresponding plurality of sampled receive signals;
• a beamformer processor comprising:
• one or more time delay elements coupled to the receiver and configured to impose a time delay on each sampled receive signal to generate a corresponding plurality of delayed receive signals;
• a summer coupled to the one or more time delay elements and configured to sum at least two delayed receive signals to generate a beamsum signal, wherein each of the delayed receive signals comprises a corresponding receiver time delay;
• a complex filter coupled to the summer and configured to transform the beamsum signal to a complex analytic signal;
• and
• a plurality of correlator processors each coupled to at least one respective transducer array element and the complex filter, wherein each correlator processor is configured to estimate a time delay error by comparing the complex analytic signal from the complex filter and a delayed receive, and wherein the beamformer processor is configured to correct the beamforming time delays for each transducer array element corresponding to each of the receive signals.