Estimation of transducer translation using channel-domain correlation

Swept synthetic aperture imaging has been previously proposed as a method of extending the effective size of an ultrasound transducer to improve lateral resolution, especially at depth. This method requires precise knowledge of array position and orientation in space as it is moved across a field of view. Previous experimental realizations have used motorized translation stages or calibrated measurement arms to track the transducer. We demonstrate a 1 degree-of-freedom sweep device that constrains the transducer motion and enables a new channel-domain motion estimation method. This channel correlation method is compared against conventional speckle tracking motion estimation and the known applied motion from a motorized stage. Swept synthetic aperture was successfully performed in a phantom using both estimators without external position tracking to extend a 2 cm transducer over a 5 cm sweep and achieve a lateral resolution improvement of 70%.