GUIDED CALIBRATION OF MEDICAL STEREO ENDOSCOPES

Abstract

Using stereo endoscopes for 3D reconstruction in minimally invasive surgery, the calibration of the stereo system is required. Since calibration in general and of medical endoscopes in particular is a well discussed topic, this publication will focus on the user experience in the operating room. To enable the medical personnel in performing the calibration, a guided process using an augmented camera image has been developed and implemented on the basis of the Robot Operating System framework. A similarly guided accuracy check allows the user to determine beforehand if a calibration is necessary.The method is tested by performing multiple calibrations on two different stereo endoscopes. It is shown, that the accuracy check and calibration can be completed in around 2 minutes. The resulting calibration parameters for one endoscope are analyzed in terms of temporal stability. Additionally, the self-heating that occurs after the system starts is examined. It is shown that short- and long-term effects impact the stereo system stability and that regular re-calibrations might be required for use in 3D reconstruction.