Calibration of multiple aperture ultrasound probes
The quality of ping-based ultrasound imaging is dependent on the accuracy of information describing the precise acoustic position of transmitting and receiving transducer elements. Improving the quality of transducer element position data can substantially improve the quality of ping-based ultrasound images, particularly those obtained using a multiple aperture ultrasound imaging probe, i.e., a probe with a total aperture greater than any anticipated maximum coherent aperture width. Various systems and methods for calibrating element position data for a probe are described.
1. A method of calibrating ultrasound imaging data obtained with an ultrasound imaging device, comprising the steps of:
retrieving raw echo data from a memory device, the raw echo data comprising a plurality of echo strings, each echo string comprising a collection of echo records corresponding to echoes of a single ultrasound ping transmitted from a single transmit aperture of the ultrasound imaging device and received by a single receive element of the ultrasound imaging device;
retrieving first calibration data from the memory device describing a position of each receive transducer element corresponding to each echo string;
retrieving second calibration data from the memory device describing a position of at least one transducer element of the ultrasound imaging device corresponding to a transmitted ping associated with each echo string;
forming a reference image by beamforming a first collection of echo strings corresponding to a first group of receive transducer elements, wherein beamforming comprises triangulating a position of reflectors based on the first and second calibration data;
forming a test image by beamforming a second collection of echo strings corresponding to a second group of transducer elements of the ultrasound imaging device that is not identical to the first group of transducer elements;
quantifying a first error between the reference image and the test image;
adjusting the first calibration data to describe adjusted positions for the transducer elements of the second group;
re-beamforming the test image with the adjusted positions for the transducer elements of the second group to obtain a second test image;
quantifying a second error between the second test image and the reference image; and
evaluating the new error to determine whether the second error is less than the first error.
2. The method of claim 1 , wherein the method is performed without any physical or electronic connection to a probe used to create the raw echo data.