Hybrid systems for reconstruction of freehand 3D ultrasound data

Freehand 3D ultrasound can be acquired without a position sensor by finding the separations of pairs of frames using information in the images themselves. However, small biases in the offset estimates lead to large scale drift in the final reconstruction. In comparison, position sensors have good large scale accuracy, but are inconvenient to use. In this paper, we present methods that combine existing sensorless techniques with limited information from a position sensor, in order to reduce drift errors. We also consider two novel position sensors that are potentially less inconvenient and we assess their accuracy for the purpose of drift correction.