PRO-TIP: Phantom for RObust automatic ultrasound calibration by TIP detection
This provides a robust, automatic calibration method for ultrasound probes, improving ease of use for medical imaging applications, though it is incremental over existing techniques.
The authors tackled the problem of automatically calibrating tracked ultrasound probes by designing a 3D-printed phantom with nine cones and using a CNN to detect tips, achieving results comparable to expert calibrations.
We propose a novel method to automatically calibrate tracked ultrasound probes. To this end we design a custom phantom consisting of nine cones with different heights. The tips are used as key points to be matched between multiple sweeps. We extract them using a convolutional neural network to segment the cones in every ultrasound frame and then track them across the sweep. The calibration is robustly estimated using RANSAC and later refined employing image based techniques. Our phantom can be 3D-printed and offers many advantages over state-of-the-art methods. The phantom design and algorithm code are freely available online. Since our phantom does not require a tracking target on itself, ease of use is improved over currently used techniques. The fully automatic method generalizes to new probes and different vendors, as shown in our experiments. Our approach produces results comparable to calibrations obtained by a domain expert.