Effect of Active Air Conditioning in Medical Intervention Rooms on the Temperature Dependency of Time-of-Flight Distance Measurements

Recently, Time-of-Flight (ToF) cameras have emerged as a new mean for intra-operative image acquisition. The ToF camera features co-registered depth and intensity image data from the observed scene in video frame rate. Due to systematic distance errors, depth calibration is crucially needed. One of the sources of error that so far received little attention in literature related to ToF camera calibration is the temperature of the camera’s video chip. In this work we address the effect of active air conditioning in medically used rooms on the temperature related distance variability. The conducted experiments in which data were acquired over a long time indicate a reduction of the runtime related distance drift by up to factor five and a reduction of the measurement offset by factor three for certain examined ToF cameras in actively compared to passively climate controlled rooms. This has important implications on the ToF camera depth calibration process, for the calibration of the temperature related distance deviation in rooms with active air conditioning can be reduced to an easy to determine offset.