Dual Transducer Motion Estimation

Example of lateral motion images tracked using a conventional correlation method and the dual transducer technique.

(a) Conventional correlation method

(b) Dual transducer method

Due to the physics of ultrasound, image quality is highest in the direction of the travelling sound wave (axial) and is poorer in the other directions (lateral and elevational). Consequently, when trying to estimate tissue motion using ultrasound images, the estimation is most accurate along the axial direction followed by the lateral and the elevational directions.

Motion between two ultrasound images is typically tracked by breaking the image up into a number of blocks. The motion is estimated by finding the best match between a block from the first image and a block in the second image. The best match is computed by calculating the correlation coefficient.

An example of a noisy lateral displacement image using conventional correlation tracking is shown on the right in Fig. (a). A substantial improvement is seen when using the dual transducer technique Fig. (b).