Cross-Wire Calibration for Freehand 3D Ultrasonography: Measurement and Numerical Issues

Abstract

3D freehand ultrasound is an imaging technique, which is graduallyfinding clinical applications. A position sensor is attached to aconventional ultrasound probe, so that B-scans are acquired along withtheir relative locations. This allows the B-scans to be inserted into a3D regular voxel array, which can then be visualized usingarbitrary-plane slicing, and volume or surface rendering. A keyrequirement for correct reconstruction is the calibration: determiningthe position and orientation of the B-scans with respect to theposition sensor's receiver. Following calibration, interpolation in theset of irregularly spaced B-scans is required to reconstruct aregular-voxel array. This text describes a freehand measurement of 2Dultrasonic data, an approach to the calibration problem and severalnumerical issues concerned with the calibration and reconstruction.