Illumination and imaging system with glare reduction and method therefor

• US 7,646,422 B2
• Filed: 10/04/2006
• Issued: 01/12/2010
• Est. Priority Date: 10/04/2006
• Status: Active Grant

• Current Assignee: Aptiv Technologies AG (Aptiv PLC)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Kisacanin, Branislav, Newman, Timothy J.
• Primary Examiner(s): Jerabek; Kelly L
• Application Number:
  US11/542,980
• Publication Number:
  US 20080084499A1
• Time in Patent Office: 1,196 Days
• Field of Search: 348/169, 348/170, 348/171, 348/77, 348/78, 348/370, 382/103, 382/115, 382/117
• US Class Current: 348/370
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• 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: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06V 10/141 Control of illumination

Abstract

A system and method are provided for actively illuminating and capturing images of an object, such as a driver of a vehicle to reduce glare. The system includes a video imaging camera orientated to generate images of the subject object (e.g., eye(s)) in successive video frames. The system also includes first and second light sources operable to illuminate the object one at a time. The system further includes a processor for processing the image by performing pixel-wise min operation to combine multiple frames into a single frame to reduce glare in the image. The system may remove glare caused by the illuminators and caused by external energy sources.

Claims

1. An active illumination imaging system for monitoring an object and capturing video images, said system comprising:

a video imaging camera oriented to generate video images of an object in successive video frames;

a first light source located at a first location and operable for illuminating the object;

a second light source located at a second location and operable for illuminating the object, wherein the first and second light sources generate a three-state sequence in synchronization with the video frames; and

a processor for processing the video images generated with the video imaging camera, said processor performing a pixel-wise minimum operation to combine multiple frames into a single image to reduce glare and shadow images in the image;

wherein a new image in the pixel-wise minimum operation is a function of the three-state sequence.

2. The system as defined in claim 1, wherein the object comprises an eye.

3. The system as defined in claim 2, wherein the system is employed in a vehicle for monitoring the eye of a driver of the vehicle.

4. The system as defined in claim 1, wherein the video imaging camera has an imaging axis and the first and second light sources are located on opposite sides of the imaging axis.

5. The system as defined in claim 4, wherein the first and second light sources are each located at an angle in the range of two to four degrees relative to the imaging axis.

6. The system as defined in claim 1, wherein the first and second light sources each comprise a light emitting diode.

7. The system as defined in claim 1, wherein the processor controls the three-state sequence.

8. The system as defined in claim 1, wherein the processor activates and deactivates the first and second light sources.

9. The system as defined in claim 1, wherein the three-state sequence has a repeating sequential order comprising a first state of activating the first light source only, a second state of activating the second light source only, and a third state of deactivating the first and second light sources.

10. An active illumination imaging system for monitoring an object and capturing video images, said system comprising:

a video imaging camera oriented to generate video images of an object in successive video frames;

a first light source located at a first location and operable for illuminating the object;

a second light source located at a second location and operable for illuminating the object, wherein the first and second light sources generate alternating light beams in synchronization with the video frames; and

a processor for processing the video images generated with the video imaging camera, said processor performing a pixel-wise minimum operation to combine multiple frames into a single image to reduce glare in the image, wherein the first and second light sources and the camera are contained in a housing and the first and second light sources are each located at a distance within about 2.5 to 5.0 centimeters from the camera.

11. An active illumination vehicle eye monitoring system for monitoring and capturing video images of an eye of a person in a vehicle, said system comprising:

a video imaging camera located on a vehicle and oriented to generate video images of an eye of a person in the vehicle in successive video frames;

a first light source located on the vehicle and arranged along a first axis for illuminating the eye;

a second light source located on the vehicle and arranged along a second axis offset from the first axis for illuminating the eye, wherein the first and second light sources generate a three-state sequence in synchronization with the video frames; and

a processor for processing the video images generated with the video imaging camera, said processor performing a pixel-wise minimum operation to combine multiple frames into a single image to reduce glare and shadow images in the image;

wherein a new image in the pixel-wise minimum operation is a function of the three-state sequence.

12. The system as defined in claim 11, wherein the video imaging camera has an imaging axis and the first and second light sources are located on opposite sides of the imaging axis.

13. The system as defined in claim 12, wherein the first and second light sources are each located at an angle in the range of two to four degrees relative to the imaging axis.

14. The system as defined in claim 11, wherein the first and second light sources each comprise a light emitting diode.

15. The system as defined in claim 11, wherein the processor controls the three-state sequence.

16. The system as defined in claim 11, wherein the processor activates and deactivates the first and second light sources.

17. The system as defined in claim 11, wherein the three-state sequence has a repeating sequential order comprising a first state of activating the first light source only, a second state of activating the second light source only, and a third state of deactivating the first and second light sources.

18. An active illumination vehicle eye monitoring system for monitoring and capturing video images of an eye of a person in a vehicle, said system comprising:

a video imaging camera located on a vehicle and oriented to generate video images of an eye of a person in the vehicle in successive video frames;

a first light source located on the vehicle and arranged along a first axis for illuminating the eye;

a second light source located on the vehicle and arranged along a second axis offset from the first axis for illuminating the eye, wherein the first and second light sources generate alternating light beams in synchronization with the video frames; and

a processor for processing the video images generated with the video imaging camera, said processor performing a pixel-wise minimum operation to combine multiple frames into a single image to reduce glare in the image;

wherein the video imaging camera has an imaging axis and the first and second light sources are located on opposite sides of the imaging axis and each of the light sources is located at an angle in the range of two to four degrees relative to the imaging axis, and the first and second light source and the camera are contained in a housing and the first and second light sources are each located at a distance within about 2.5 to 5.0 centimeters from the camera.

19. A method for actively illuminating and capturing images of an object, said method comprising the steps of:

arranging a video imaging camera to generate images of an object;

arranging a first light source at a first location;

arranging a second light source at a second location;

illuminating the object with light using a three-step sequence generated by the first and second light sources wherein the first and second light sources are activated and deactivated;

generating video images of the object in successive frames in synchronization with the three-state sequence; and

processing the captured video frames by performing a pixel-wise minimum operation that is a function of the three-step sequence to combine multiple frames into a single image to reduce glare and shadows in the image.

20. The method as defined in claim 19, wherein the object comprises an eye.

21. The method as defined in claim 20, wherein the method is employed for monitoring the eye of a driver of a vehicle.

22. The method as defined in claim 20, wherein the steps of arranging the video imaging camera, first light source, and second light source comprises arranging the video imaging camera on an imaging axis, arranging the first light source on one side of the imaging axis and arranging the second light source on an opposite side of the imaging axis.

23. The method as defined in claim 22, wherein the steps of arranging the first and second light sources further comprises arranging the first and second light sources at an angle in the range of two to four degrees relative to the imaging axis.

24. The method as defined in claim 19, wherein the step of illuminating further comprises the three-state sequence having a repeating sequential order including a first state of activating the first light source only, a second state of activating the second light source only, and a third state of deactivating the first and second light sources.

25. A method for actively illuminating and capturing images of an object, said method comprising the steps of:

arranging a video imaging camera to generate images of an object;

arranging a first light source at a first location;

arranging a second light source at a second location;

illuminating the object with light generated by the first and second light sources, wherein the first and second light sources are alternately activated to generate first and second alternating light beams;

generating video images of the object in successive frames in sync with the alternating first and second light beams; and

processing the captured video frames by performing a pixel-wise min operation to combine multiple frames into a single image to reduce glare in the image;

wherein the object comprises an eye and the steps of arranging the video imaging camera, first light source, and second light source comprises arranging the video imaging camera on an imaging axis, arranging the first light source on one side of the imaging axis and arranging the second light source on an opposite side of the imaging axis, and the first and second light sources and the camera are contained in a housing, and the first and second light sources are each located at a distance in the range of about 2.5 to 5.0 centimeters from the video imaging camera.