An optical "Time-of-Flight" (ToF) sensor emits light with modulated brightness. Surrounding objects reflect or scatter some of this light back to the sensor. The circulation time and brightness of this light is measured. This enables a variety of applications, such as 3D distance measurement or the analysis of aerosols, gases, and clouds in the atmosphere. “Time-of-Flight 3D imaging” sensors allow spatially resolved distance measurements and therefore 3D mapping. Thanks to these characteristics, they are often used in autonomous vehicles as well as in robots. Environmental factors such as rain, fog, or snow can affect the determination of distance to surrounding objects. The quantification and development of measuring strategies to avoid or separate these environmental influences is the subject of current research in the IoSense project* at the CTR. A toolbox for the simulation of the optical effects of “Time-of-Flight 3D imaging” sensors has already been implemented, and the impact of rain and fog on the sensor signals has been quantified. The graphic above shows the result for heavy rain. The individual rain drops are clearly discernible. These results serve as a basis for the development of appropriate filter and compensation strategies. This can significantly improve the precision of such sensors and expand their range of application.
Link: Project IoSense
* The IoSense project is supported by the ECSEL JU (Electronic Component Systems for European Leadership Joint Undertaking). The joint undertaking program is supported by funds from the European Horizon 2020 program as well as by Austria, Belgium, Germany, Saxony, the Netherlands, Slovakia, and Spain. The project is co-financed by the Austrian Research Promotion Agency (FFG).