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Driver head pose sensing using a capacitive array and a time-of-flight camera

University of British Columbia

Improving the safety of vehicle occupants has gained increasing attention among automotive manufacturers and researchers over the past three decades. There is increased potential for injury mitigation techniques to be applied more effectively to vehicle safety systems if the pose (i.e. the position and orientation) of the driver’s head with respect to the Head Restraint (HR) device can be provided to such safety systems in real-time during vehicle operation. This information is valuable to a range of systems including: adaptive HR positioning for whiplash injury mitigation, advanced driver assistance, driver inattention and fatigue detection, and other possible applications. This thesis proposes, implements, and evaluates a new integrated hybrid sensing approach to providing the driver’s head pose both accurately and in real-time by employing two different sensing subsystems inside the vehicle: 1) a novel capacitive proximity sensing array, and 2) an Illumination-Compensated (IC) Time-of-Flight (ToF) range imaging camera. Firstly, for position sensing, a capacitive proximity sensing electrode and array were developed through electrostatic field analysis and then optimized using numerical modeling studies. Experiments (including environmental testing) using a full system prototype of the position sensing array were performed for numerical modeling validation and accuracy testing. Secondly, since orientation sensing (found to be inaccurate with capacitive sensing alone), this work demonstrated how a ToF camera can be utilized to obtain an accurate measurement of the driver’s head pose using a novel light IC technique. A laboratory testbed was also built to accommodate the aforementioned hybrid system. The capacitive array was incorporated inside the frontal compartment of a customized HR device as part of the testbed, and the ToF camera was installed in front of the driver. Laboratory experiments have demonstrated that the head position can be estimated with a mean Euclidean distance error of 0.33 cm and a Mean Absolute Error in orientation of 3.45° and 1.61° for head yaw and pitch angles, respectively. The thesis also contains a comprehensive introduction to the problem, review of relevant current literature in the area, comparison with the findings of previous related investigations, discussion of the implications of the work and suggestions for future work.

Text

2014-08-26

Attribution-NonCommercial-NoDerivs 2.5 Canada

http://hdl.handle.net/2429/50186

Electrical and Computer Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/2.5/ca/