Acoustic lens error compensation in ultrasonic probes for spatial compounding using image registration

Spatial compounding is an speckle reducing imaging technique in which a number of ultrasound images of a given target that have been obtained from multiple angles are combined into a single compounded image by combining the data received from each data point in the compounded image. The ultrasonic beams are steered at desired angles electronically by controlling the ultrasonic transducer element arrays. The ultrasonic beam produced by the transducer array undergoes refraction at the surface of the acoustic lens. However, since the acoustic properties of the acoustic lens are not known exactly, the exact refraction is not known. The uncertainties in the refraction angle leads to the image position error and results in the blurring of the compounded images. In this paper, we study a compensation method using image registration that can reduce the lens artifact.