Driver photographing apparatus

• US 5,598,145 A
• Filed: 08/10/1994
• Issued: 01/28/1997
• Est. Priority Date: 11/11/1993
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Morihiro, Yoshiharu, Shimotani, Mitsuo, Okada, Akira, Nishida, Minoru
• Primary Examiner(s): MULLEN, THOMAS J
• Application Number:
  US08/288,936
• Time in Patent Office: 902 Days
• Field of Search: 340/576, 340/575, 180/272
• US Class Current: 340/576
• CPC Class Codes: A61B 3/145 by video means
• 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: B60L 3/02 Dead-man's devices
• CPC Class Codes: G08B 21/06 indicating a condition of sleep, e.g. anti-dozing alarms

Abstract

A driver photographing apparatus that photographs images from reflections on the retinas of a driver in a vehicle having disturbance light using signal processing techniques. The apparatus comprises a light source for illuminating the driver with a first light beam along a first optical path, and a sensor that inputs a second light beam, along a second optical path, that includes reflections from the driver and disturbance light, to form an image of the driver. The light source and the sensor are disposed such that the first and second optical paths are along substantially the same axis. The apparatus further includes a processing circuit that eliminates the effect of the disturbance light on the image of the driver, and a detecting circuit that determines the action of the driver based on the driver'"'"'s image.

Claims

1. A driver photographing apparatus for monitoring a driver in a vehicle wherein background light is present, the driver having eyes with pupils, the photographing apparatus comprising:

an illuminating means for illuminating the driver with a first beam of light along a first optical path, the first beam of light being reflected from the driver to form a second beam of light along a second optical path, the second beam of light having a frequency;

a photographing means for forming an image based upon light received at the photographing means, the photographing means being disposed along the second optical path so that the photographing means receives the second beam of light and forms an image of said driver, the first and second optical paths being along a substantially same axis; and

limiting means for limiting an effect of the background light on the image, the limiting means including means for limiting the effect on the image of components of the background light at the frequency of the second beam of light.

2. The driver photographing apparatus according to claim 1, wherein the limiting means includes passing means for passing the second beam of light and for limiting passage of the background light through the passing means, said passing means being disposed on the second optical path between the driver and the photographing means.

3. The driver photographing apparatus according to claim 1, wherein the limiting means further includes:

an illuminating light controlling means for turning said illuminating means on and off; and

an image processing means, coupled to the photographing means, for outputting one of a first image of said driver formed when the illuminating means is turned on, a second image of said driver formed when the illuminating means is turned off, and a third image of said driver that is formed from a difference between the first image and the second image.

4. A driver photographing apparatus for monitoring a driver in a vehicle wherein disturbance light is present, the driver having eyes with pupils, the photographing apparatus comprising:

an illuminating means for illuminating the driver with a first beam of light along a first optical path, the first beam of light being reflected from the driver to form a second beam of light along a second optical path, the second beam of light having a frequency, the first and second optical paths being along a substantially same axis; and

a photographing means for forming an image based upon light received at the photographing means, the photographing means being disposed along the second optical path so that the photographing means receives the second beam of light and forms an image of said driver;

limiting means for limiting an effect of the background light on the image, the limiting means including means for limiting the effect on the image of components of the background light at the frequency of the second beam of light, wherein the limiting means further includes;

an illuminating light controlling means for turning said illuminating means on and off; and

an image processing means, coupled to the photographing means, for outputting one of a first image of said driver formed when the illuminating means is turned on, a second image of said driver formed when the illuminating means is turned off, and a third image of said driver that is formed from a difference between the first image and the second image; and

wherein said photographing apparatus includes a light input controlling means for controlling time periods during which light is received at the photographing means to correspond to time periods when the illuminating means is turned on.

5. The driver photographing apparatus according to claim 4, wherein said light input controlling means further controls the time periods during which light is received at the photographing means to correspond to time periods when the illuminating means is turned off.

6. A driver photographing apparatus to detect an action of a driver in a vehicle, the driver having pupils, the driver photographing apparatus comprising:

a light source that generates a first beam of light along a first path, the first beam of light having an intensity;

a deflector that deflects the first beam of light to create a second beam of light along a second path, the second path extending along an axis between the deflector and the driver, the second beam of light being reflected from the driver to form a third beam of light along a third path that extends along the axis;

a sensor that senses the third beam of light to form an image of the driver, the sensor being positioned along the axis; and

a detecting circuit, coupled to the sensor, that detects a position of the driver'"'"'s pupils from the image to determine the action of the driver.

8. The driver photographing apparatus according to claim 6, wherein background light having an intensity is present in the vehicle, and wherein the apparatus further comprises:

a filter positioned to substantially prevent the background light from reaching the sensor.

7. A driver photographing apparatus to detect an action of a driver in a vehicle wherein background light is present, the driver having pupils, the driver photographing apparatus comprising:

a light source that generates a first beam of light along a first path, the first beam of light having an intensity;

a deflector that deflects the first beam of light to create a second beam of light along a second path, the second path extending along an axis between the deflector and the driver, the second beam of light being reflected from the driver to form a third beam of light along a third path that extends

a sensor that senses the third beam of light to form an image of the driver, the sensor being positioned along the axis;

a first frame memory, coupled to the sensor, that stores a first image formed solely by the background light;

a second frame memory, coupled to the sensor, that stores a second image formed at the sensor by the third beam of light and the background light;

a timing circuit that prevents the first beam of light from reaching the driver for a first predetermined amount of time while the first image is formed, and that enables the first beam of light to reach the driver for a second predetermined amount of time while the second image is formed;

a subtracting circuit that subtracts the first image stored in the first frame memory from the second image stored in the second frame memory to form an enhanced image; and

a detecting circuit, coupled to the sensor, that detects the action of the driver from the enhanced image.

9. A driver photographing apparatus to detect an action of a driver in a vehicle, the driver having eyes with pupils, the driver photographing apparatus comprising:

an image sensor positioned opposite the driver along an axis;

a light source that directs an illuminating light beam toward the driver along the axis to form a reflected light beam that travels along the axis to the sensor, the reflected beam forming an image of the driver at the image sensor; and

detecting means, coupled to the image sensor,

for detecting a position of the driver'"'"'s pupils from the image to determine the action of the driver.

10. The driver photographing apparatus according to claim 9, wherein the vehicle has background light that can have an effect on the image, and wherein the apparatus further comprises:

means for substantially eliminating the effect of the background light on the image of the driver.

11. A driver photographing apparatus for detecting an action of a driver in a vehicle in which background light is present, the apparatus comprising:

a light source that generates a first beam of light along a first path, the first beam of light having a frequency;

a deflector that deflects the first beam of light to create a second beam of light along a second path, the second path extending along an axis between the deflector and the driver, the second beam of light being reflected from the driver to form a third beam of light along a third path that extends along the axis;

a sensor that senses light received at the sensor and forms an image based upon the light received at the sensor, the sensor being positioned along the axis in the path of the third beam of light;

limiting means for limiting an effect of the background light on the image, the light limiting means including means for limiting the effect on the image of components of the background light at the frequency of the first beam of light; and

a detecting circuit, coupled to the sensor, that determines the action of the driver based on the image.

12. The driver photographing apparatus according to claim 11, wherein the detecting circuit determines the action of the driver based on an enhanced image, and wherein the limiting means further includes:

means, coupled to the sensor, for storing a first image formed from the third beam of light and the background light received at the sensor;

means, coupled to the sensor, for storing a second image formed solely by the background light received at the sensor;

a timing circuit that prevents the first beam of light from reaching the driver for a first predetermined amount of time while the second image is formed, and that enables the first beam of light to reach the driver for a second predetermined amount of time while the first image is formed; and

a subtracting circuit that subtracts the second image from the first image to form the enhanced image.

13. A driver photographing apparatus to detect an action of a driver in a vehicle in which background light is present, the apparatus comprising:

an image sensor positioned opposite the driver along an axis;

a light source that directs an illuminating light beam toward the driver along the axis to form a reflected light beam that travels along the axis to the sensor, the reflected beam forming an image of the driver at the image sensor, the reflected light beam having a frequency;

a limiting means for limiting an effect of the background light on the image, the limiting means including means for limiting the effect on the image of components of the background light at the frequency of the reflected light beam; and

a detecting circuit, coupled to the image sensor, that determines the action of the driver based on the image.