Improving the Quality of Biomedical Signal Tracking using Prediction Algorithms

The use of optical and magnetical tracking systems is widely spread throughout modern operating theatres. One thing that is not taken into account so far is the fact that all systems which need to make two or more sequential measurements to determine an object's pose will exhibit systematic measurement errors. These errors can be attributed on the non-simultaneous acquisition process. We have analysed this problem for the atracsys accuTrack system which is an optical tracking system using three line cameras. Using robotised and manual experiments we found that, using a marker with four LEDs at a single LED acquisition rate of 331.04 Hz, these errors can be as much as 1.4 mm and 2.1° (RMS). With lower acquisiton rates - which are commonplace in other tracking systems - these errors are expected to be even higher. Using the proposed compensation methods, they may be reduced to as little as 0.2 mm and 0.6° (RMS), respectively.