COMPARISON OF FREEHAND 3D ULTRASOUND CALIBRATION TECHNIQUES USING A STYLUS
Po-Wei Hsu, Graham M. Treece, Richard W. Prager, Neil E. Houghton and Andrew H. Gee
June 2007
In a freehand 3D ultrasound system, a probe calibration is required to find the rigid body transformation from the corner of the B-scan to the electrical centre of the position sensor. The most intuitive way to perform such a calibration is by locating fiducial points in the scan plane directly with a stylus. The main problem of using this approach is the difficulty in aligning the tip of the stylus with the scan plane. The thick beam width makes the tip of the stylus visible in the B-scan even if the tip is not exactly in the elevational centre of the scan plane. In this paper, we present two novel phantoms that simplify the alignment process for more accurate probe calibration. We also compare our calibration techniques with a range of styli and show that our phantom outperforms other approaches in both accuracy and simplicity.
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