Method and apparatus for assessing head pose of a vehicle driver

• US 20080266552A1
• Filed: 04/30/2007
• Published: 10/30/2008
• Est. Priority Date: 04/30/2007
• Status: Active Grant

• Current Assignee: Aptiv Technologies AG (Aptiv PLC)
• Original Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Inventors: Malawey, Phillip V., Witt, Gerald J., Smith, Matthew R.
• Granted Patent: US 7,970,175 B2
• Time in Patent Office: Days
• US Class Current: 356/138
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60W 2540/22 Psychological state; Stress level or workload
• CPC Class Codes: B60W 2540/221 Physiology, e.g. weight, heartbeat, health or special needs
• CPC Class Codes: G06V 40/20 Movements or behaviour, e.g. gesture recognition recognition of facial expressions G06V40/16
• CPC Class Codes: G08B 21/06 indicating a condition of sleep, e.g. anti-dozing alarms

Abstract

The head pose of a motor vehicle driver with respect to a vehicle frame of reference is assessed with a relative motion sensor positioned rearward of the driver'"'"'s head, such as in or on the headrest of the driver'"'"'s seat. The relative motion sensor detects changes in the position of the driver'"'"'s head, and the detected changes are used to determine the driver'"'"'s head pose, and specifically, whether the head pose is forward-looking (i.e., with the driver paying attention to the forward field-of-view) or non-forward-looking. The determined head pose is assumed to be initially forward-looking, and is thereafter biased toward forward-looking whenever driver behavior characteristic of a forward-looking head pose is recognized.

Claims

1. Apparatus for assessing a head pose of a driver of a vehicle, comprising:

a relative motion sensor positioned to sense a posterior portion of the driver'"'"'s head and to produce a signal measuring at least lateral movements of the driver'"'"'s head; and

a signal processor responsive to the signal produced by the relative motion sensor for assessing whether the driver'"'"'s head pose is forward or non-forward relative to a forward field of view of the vehicle.

2. The apparatus of claim 1, where the relative motion sensor is an optical sensor.

3. The apparatus of claim 1, where the vehicle includes a driver seat, and the relative motion sensor is fastened to the driver seat.

4. The apparatus of claim 3, where the relative motion sensor is mounted on or in a headrest of the driver seat.

5. The apparatus of claim 1, where:

the signal processor tracks an apparent direction of the head pose based on the lateral movements sensed by the relative motion sensor, and assesses whether the driver'"'"'s head pose is forward or non-forward based on the apparent direction of the head pose.

6. The apparatus of claim 5, where:

the signal processor monitors the lateral movements sensed by the relative motion sensor to identify driver head movement behavior characteristic of a forward head pose, and changes the apparent direction of the head pose toward a forward-looking direction when driver head movement behavior characteristic of a forward head pose is identified.

7. The apparatus of claim 6, where:

the signal processor resets the apparent direction of the head pose to the forward-looking direction when driver head movement behavior characteristic of a forward head pose is identified and the assessed head pose is non-forward.

8. The apparatus of claim 6, where.

the signal processor decays the apparent direction of the head pose toward the forward-looking direction when driver head movement behavior characteristic of a forward head pose is identified and the assessed head pose is forward.

9. A method of assessing a head pose of a vehicle driver, comprising the steps of:

measuring relative lateral movements of a head of the vehicle driver by sensing a posterior portion of the head; and

processing the measured lateral movements of the head to assess whether the driver'"'"'s head pose is forward or non-forward with respect to a vehicle frame of reference.

10. The method of claim 9, where processing the measured lateral movements includes the steps of:

tracking an apparent direction of the head pose based on the measured relative lateral movements; and

assessing whether the driver'"'"'s head pose is forward or non-forward based on the apparent direction of the head pose.

11. The method of claim 10, including the steps of:

monitoring the measured relative lateral movements to identify driver head movement behavior characteristic of a forward head pose; and

adjusting the apparent direction of the head pose toward a forward-looking direction when driver head movement behavior characteristic of a forward head pose is identified.

12. The method of claim 11, including the steps of:

summing the measured relative lateral movements over a specified interval; and

identifying driver head movement behavior characteristic of a forward head pose when the summed movements are less than a calibrated threshold for at least a predetermined time.

13. The method of claim 11, including the step of:

resetting the apparent direction of the head pose to the forward-looking direction when driver head movement behavior characteristic of a forward head pose is identified and the assessed head pose is non-forward.

14. The method of claim 11, including the step of:

decaying the apparent direction of the head pose toward the forward-looking direction when driver head movement behavior characteristic of a forward head pose is identified and the assessed head pose is forward.