In one embodiment, provision is made for a signal and/or a message to be generated and output if no extraneous light signals were detected during the detection and/or synchronization is not possible. This allows a user to be informed that there is no interference with another optical tracking system or synchronization is not possible. By way of example, the signal may be an acoustic or visual signal. The message may be output for example on a display device and/or contain information that no extraneous light signals were detected and/or synchronization is not possible.

In one embodiment, provision is made for the light source to be deactivated when synchronization is not possible. This makes it possible in particular to prevent impairment of other medical optical tracking systems in the environment. In particular, the deactivation takes place if it is determined, during the synchronization, that there is not a (long enough) signal pause able to be used for the light pulses. This may occur for example when another medical optical tracking system is currently carrying out high-accuracy patient registration, in which a pulse and acquisition frequency is significantly increased compared to a normal tracking mode. It may then be the case that the remaining (extraneous) light signal pauses are too small here determine and use this.

In one embodiment, provision is made for sensor data acquired by way of the sensor or camera images acquired by way of the camera in tracking mode to be evaluated, wherein artefacts and/or errors and/or interference signals caused by extraneous light signals of the other optical tracking system are recognized, and wherein the synchronization is initiated when artefacts and/or errors and/or interference signals have been recognized. This makes it possible to determine, during ongoing (tracking) mode, whether there is any impairment caused by another medical optical tracking system. Artefacts and/or errors and/or interference signals may be recognized for example with the aid of computer vision and/or artificial intelligence methods (for example machine learning). By way of example, flicker effects, that is to say a periodic fluctuation of the average image brightness in a sequence of camera images (video), may indicate such an impairment.

Further features regarding the design of the medical optical tracking system will become apparent from the description of embodiments of the method. The advantages of the medical optical tracking system here are each the same as in the embodiments of the method.

The invention is explained in more detail below with reference to the figures using preferred exemplary embodiments. In the figures:

FIG. 1 shows a schematic illustration of one embodiment of the medical optical tracking system;

FIG. 2 shows a schematic illustration for elucidating the synchronization;

FIG. 3 shows a schematic illustration for elucidating the temporal properties of the extraneous light signals and the light signals after the synchronization in tracking mode.

FIG. 1 shows a schematic illustration of one embodiment of the medical optical tracking system 1. The medical optical tracking system 1 comprises a sensor 2 or a camera 3, a light source 4 and a control device 5. The medical optical tracking system 1 in particular performs the method described in this disclosure.

The sensor 2 or the camera 3 is configured to detect light 6 emitted by the light source 4 and reflected or remitted in an environment within a detection range of the sensor 2 or the camera 3 from objects and/or features and/or markers such that it is possible to determine a position and orientation of objects, features and/or markers in the environment based on acquired sensor data 10 or acquired camera images 11. To this end, the light source 4 emits in particular light signals 6 in the form of successive light pulses 7 at regular intervals. A repetition rate or frequency of the light pulses 7 is in particular here in a range between 20 and 120 Hz.

The control device 5 is configured to control the light source 4 and to determine the position and orientation based on the acquired sensor data 10 or acquired camera images 11. This tracking takes place in particular in a manner known per se. The light source 4 and the sensor 2 or the camera 3 operate in particular in a non-visible wavelength range of light, in particular in the infrared wavelength range.

The control device 5 is furthermore configured to perform synchronization with at least one other medical optical tracking system 20. FIG. 1 shows, by way of example, another medical optical tracking system 20 that is designed basically like the tracking system 1, that is to say the other tracking system 20 comprises a camera 21, for example a stereo camera, a light source 22 and a control device 23. The light source 22 emits extraneous light signals 24, in particular in the form of a pulse sequence.

For the synchronization, the sensor data 10 acquired by way of the sensor 2 or the camera images 11 acquired by way of the camera 3, which comprise and/or represent the extraneous light signals 24 of the other optical tracking system 20, are obtained by the control device 5. The sensor data 10 or camera images 11 in particular contain a temporal profile of the extraneous light signals 24 and/or represent same. The control device 5 determines temporal properties of the detected extraneous light signals 24 based on the obtained sensor data 10 or the obtained camera images 11 and defines temporal properties of the light signals 6 generated by way of the light source 4 and/or a temporal measuring window of the sensor 2 or the camera 3 on the basis of the determined temporal properties of the extraneous light signals 24 such that the light signals 6 from the light source 4, in particular the light pulses 7, and/or the measuring window lie in light signal pauses of the other optical tracking system 20.

FIG. 2 shows a schematic illustration for elucidating the synchronization. The following are each shown over time against time t: Extraneous light signals 24 and measuring windows 9 of another medical optical tracking system, acquired sensor data 10 or a signal derived from the camera images 11, light signal pauses 12 derived from the sensor data 10 or the camera images 11, and the light signals 6 from the light source and the measuring windows 8 of the medical optical tracking system.

The extraneous light signals 24 comprise a regular sequence of extraneous light pulses 25 (only one of these is provided with a reference sign for the sake of clarity). This sequence of extraneous light pulses 25 is detected by way of the sensor or the camera, and is therefore included in the sensor data 10 or the camera images 11. A highly simplified illustration has been selected here for the camera images 11 for the sake of clarity, but the acquired camera images 11 are in particular evaluated in order to extract the information contained therein regarding the detected extraneous light pulses