Method and system for detecting operator alertness

• US 7,692,549 B2
• Filed: 02/06/2007
• Issued: 04/06/2010
• Est. Priority Date: 09/12/2006
• Status: Active Grant

• Current Assignee: Deere & Company
• Original Assignee: Deere & Company
• Inventors: Bonefas, Zachary Thomas, Sanchez, Julian
• Primary Examiner(s): Bugg; George A
• Application Number:
  US11/671,530
• Publication Number:
  US 20080068185A1
• Time in Patent Office: 1,155 Days
• Field of Search: 340/575, 340/576, 340/439, 340/573.1, 340/540, 382/2, 382/117, 382/203, 382/291, 434/236, 351/206, 351/209, 351/246
• US Class Current: 340/575
• CPC Class Codes: A61B 5/163 by tracking eye movement, gaze, or pupil change
• CPC Class Codes: A61B 5/18 for vehicle drivers or machine operators
• CPC Class Codes: B60K 28/066 actuating a signalling device B60K28/063 takes precedence
• CPC Class Codes: G06V 20/59 inside of a vehicle, e.g. relating to seat occupancy, driver state or inner lighting conditions
• CPC Class Codes: G06V 40/161 Detection; Localisation; Normalisation
• 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 method and system for detecting operator alertness of an operator of a vehicle or machine comprises an image collection system. The image collection system collects reference motion data associated with an operator representation when the operator is in an alert state. An image processor determines observed motion data of one or more points of a three dimensional representation of the operator during a time interval. An analyser sends an alert signal to alert the operator if a detected angular shift of one or more points of the representation exceed a motion threshold.

Claims

1. A method for detecting operator alertness of an operator of a vehicle or machine, the method comprising:

collecting reference motion data associated with an operator representation of the operator when the operator is in an alert state, wherein the collecting reference motion data comprises creating at least two three dimensional representations of the operator, or a portion thereof, over a first time period via stereo vision processing;

determining observed motion data of one or more points of a three dimensional representation of the operator during a time interval, wherein a change in position versus time is determined for the one or more points of the three dimensional representation of the operator; and

sending an alert signal to alert the operator if a detected angular shift of one or more points of the representation exceed a motion threshold.

2. The method according to claim 1 wherein the determining observed motion data comprises creating at least two three dimensional representations of the operator, or the portion thereof, over a second time period via stereo vision processing.

3. The method according to claim 1 wherein the collecting reference motion data further comprises:

gathering a pair of raw stereo scene images of the operator, or the portion thereof, from spatially offset perspectives;

identifying respective operator-related image data in the gathered raw stereo scene images;

combining at least one of (i) the raw stereo scene images together with each other and (ii) the operator-related image data together with each other to produce a disparity map image that represents a disparity between the raw stereo scene images; and

creating at least one of the three dimensional representations of the operator, or the portion thereof, based on the disparity map and the raw stereo scene images.

4. The method according to claim 1 wherein the determining observed motion data further comprises:

gathering a pair of raw stereo scene images of the operator, or the portion thereof, from spatially offset perspectives;

identifying respective operator-related image data in the gathered raw stereo scene images;

combining at least one of (i) the raw stereo scene images together with each other and (ii) the operator-related image data together with each other to produce a disparity map image that represents a disparity between the raw stereo scene images; and

creating at least one of the three dimensional representation of the operator, or the portion thereof, based on the disparity map and the raw stereo scene images.

5. The method according to claim 1 wherein the reference motion data comprises movement associated with three dimensional coordinates of one or more reference points associated with the operator, or the portion thereof.

6. The method according to claim 1 wherein the reference motion data comprises movement associated with a reference axis defined by two reference points lying on a surface of the operator'"'"'s head, and their respective three dimensional coordinates, when the operator is in an alert state.

7. The method according to claim 1 wherein the observed motion data comprises movement associated with three dimensional coordinates of one or more reference points associated with the operator, or the portion thereof.

8. The method according to claim 1 wherein the observed motion data comprises movement associated with a reference axis defined by two reference points lying on a surface of the operator'"'"'s head, and their respective three dimensional coordinates.

9. The method according to claim 1 wherein the detected angular shift represents an inclination forwards, backwards, or sideways of one or more reference points during the time interval.

10. The method according to claim 1 wherein the reference points define an observed axis and wherein the detected angular shift represents an inclination forwards, backwards or sideways of the observed axis with respect to a generally vertical axis by at least a critical angle during the time interval.

11. A system for detecting operator alertness of an operator of a vehicle or machine, the system comprising:

a stereo vision image collection system for collecting reference motion data associated with an operator representation of the operator when the operator is in an alert state, wherein the reference position data comprises a three dimensional representation of the operator, or a portion thereof, created via stereo vision processing by the stereo vision image collection system;

an image processor for determining observed motion data of one or more points of a three dimensional representation of the operator during a time interval, wherein a change in position versus time is determined for the one or more points of the three dimensional representation of the operator; and

an analyzer for sending an alert signal to alert the operator if a detected angular shift of one or more points of the representation exceed a motion threshold.

12. The system according to claim 11 wherein the image processor further comprises an image former for creating a three dimensional representation of the operator, or the portion thereof.

13. The system according to claim 11 further comprising:

a plurality of imaging units for gathering a pair of raw stereo scene images of the operator, or the portion thereof, from spatially offset perspectives;

an image segmenter for identifying respective operator-related image data in the gathered raw stereo scene images;

an image disparity module for combining (i) at least one of the raw stereo scene images together with each other and (ii) the operator-related image data together with each other to produce a disparity map image that represents a disparity between the raw stereo scene images; and

an image former for creating a three dimensional representation of the operator, or the portion thereof, based on the disparity map and the raw stereo scene images.

14. The system according to claim 11 wherein the reference motion data comprises movement associated with three dimensional coordinates of one or more reference points associated with the operator, or the portion thereof.

15. The system according to claim 11 wherein the observed motion data comprises movement associated with three dimensional coordinates of one or more reference points associated with the operator, or the portion thereof.

16. The system according to claim 11 wherein the reference motion data comprises movement of a reference axis defined by two reference points lying on a surface of the operator'"'"'s head, and their respective three dimensional coordinates, when the operator is in an alert state.

17. The system according to claim 11 wherein the observed motion data comprises movement of three dimensional coordinates of one or more reference points associated with the operator, or the portion thereof.

18. The system according to claim 11 wherein the observed motion data comprises movement of a reference axis defined by two reference points lying on a surface of the operator'"'"'s head, and their respective three dimensional coordinates.

19. The system according to claim 11 wherein the detected angular shift represents an inclination forwards, backwards, or sideways of one or more reference points during the time interval.

20. The system according to claim 11 wherein the reference points define an observed axis and wherein the detected angular shift represents an inclination forwards, backwards or sideways of an observed axis with respect to a generally vertical axis by at least a critical angle during the time interval.