Correction of Probe Pressure Artifacts in Freehand 3D Ultrasound

Abstract

Abstract. We present an algorithm which combines non-rigid imagebased registration and conventional position sensing to correct probepressure-induced registration errors in freehand three-dimensional (3D) ultrasound volumes. The local accuracy of image-based registration enables the accurate freehand acquisition of high resolution (> 15MHz) 3D ultrasound data, opening the way for 3D musculoskeletal examinations. External position sensor readings guarantee the large-scale positional accuracy of the data. The algorithm is shown to increase both the clarity and accuracy of reslices through in vivo volumetric data sets.

Subsample interpolation strategies for sensorless freehand 3D ultrasound

“…Here, we once again consider two functions at opposite ends of the speed-accuracy spectrum. The fastest way to estimate the correlation peak is to fit a symmetric triangular function to the highest three samples [15], as illustrated in Figure 3. This produces results which are very similar to quadratic interpolation through the three highest samples, but is slightly quicker to compute.…”

“…A minimum of three such lookups, for three (non-collinear) pairs of patches, allows us to estimate the elevational separation, tilt and yaw of A relative to B. Any in-plane motion between A and B (translation in the axial and lateral directions, roll around the elevational axis) can be determined using 2D image registration techniques [14,15].…”

Rapid, easy and reliable calibration for freehand 3D ultrasound

“…For a linear probe, the correction is a translation of each likely edge point toward the probe face; the axial coordinates v of the points are multiplied by the temperature correction factor t = In the scenario of a curvilinear probe, the plane appears as a curve rather than a line. We therefore first detect the probe shape automatically [21]. The probe centre is then the intersection of the left and right edges.…”

Speckle classification for sensorless freehand 3-D ultrasound

“…To this end, we chose to perform an in vitro experiment. In vivo experiments are subject to additional factors that degrade speckle-based distance measurement, including the movement of the soft tissue due to breathing, muscular tremor, circulatory motion and the contact pressure of the probe itself [28].…”