Image processing system which processes an image captured by an imaging device through a lens having a focus which is adjusted to a point beyond the glass

• US 7,208,723 B2
• Filed: 08/12/2004
• Issued: 04/24/2007
• Est. Priority Date: 08/12/2003
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Otsuka, Yuji, Muramatsu, Shoji, Monji, Tatsuhiko, Furusawa, Isao, Fukuhara, Masaaki, Ohsumi, Ken, Kasuya, Hiroyuki, Takenaga, Hiroshi
• Primary Examiner(s): Epps; Georgia
• Assistant Examiner(s): MONBLEAU, DAVIENNE N
• Application Number:
  US10/916,444
• Publication Number:
  US 20050035926A1
• Time in Patent Office: 985 Days
• Field of Search: 250/208.1, 250/227.25, 250/574, 318/643, 340/601, 340/602, 340/438, 73/290.1, 73/290.2, 733/350.1, 73/290.4, 73/290.5
• US Class Current: 250/227.25
• CPC Class Codes: B60S 1/0818 including control systems responsive to external conditions, e.g. by detection of moisture, dirt or the like
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• CPC Class Codes: B60S 1/0833 Optical rain sensor
• CPC Class Codes: B60S 1/0844 including a camera
• CPC Class Codes: B60S 1/0896 including control systems responsive to a vehicle driving condition, e.g. speed
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle

Abstract

An image processing system that detects foreign matter on a glass window of a vehicle and objects in front of the vehicle. The system includes an image processor, a first lamp, and a second lamp. On/off control of the first and second lamps is controlled by the image processor. Light from the first lamp is reflected from the outer sauce of the glass when raindrops are present on the outside of the glass. Light from the second lamp is reflected from the inner surface of the glass when moisture is present on the inside of the glass. Any reflected light goes through a lens and an optical filter with prescribed optical characteristics to an image device. The lens is focused to a point beyond the window so that the image processor an also detect objects in front of the vehicle.

Claims

1. An image processing system comprising:

a lamp;

an imaging device which captures light which is emitted from the lamp and reflected by foreign matter on the glass;

an optical filter, located in front of the imaging device, a portion of the optical filter being an infrared wavelength transmitting area which transmits rays with an infrared wavelength of the reflected light;

an image processor which processes an image portion corresponding to the infrared wavelength transmitting area of the optical filter in an image captured by the imaging device so as to detect the foreign matter on the glass; and

a lens which is provided in front of the imaging device, the lens having a focus which is adjusted to a point beyond the glass to distinguish the foreign matter on the glass from objects that exist in front of the glass.

2. The image processing system as claimed in claim 1, wherein the imaging device has an area for receiving light through the optical filter and an area for receiving external light passing through the glass, without the intervention of the optical filter.

3. The image processing system as claimed in claim 1, wherein an infrared cut filter is provided between the optical filter and the glass.

4. The image processing system as claimed in claim 1, wherein the glass is a windshield of a vehicle and not only foreign matter on the glass but also a taillight of another vehicle in front are detected.

5. The image processing system as claimed in claim 1, wherein the optical filter has areas with different optical characteristics.

6. The image processing system as claimed in claim 5, wherein in the optical filter, one area is used as an infrared cut area and at least one of areas other than the infrared cut area is used as an infrared bandpass area with a peak transmittance in the infrared band.

7. The image processing system as claimed in claim 6, wherein the upper area of the optical filter constitutes the infrared bandpass area when the optical filter is located between the glass and the imaging device.

8. The image processing system as claimed in claim 6, wherein the upper area of the optical filter constitutes the infrared band pass area and the lower area constitutes the infrared cut area when the optical filter is located between the glass and the imaging device.

9. The image processing system as claimed in claim 6, wherein the lens has a coating with the same optical characteristics as those of the optical filter.

10. The image processing system as claimed in claim 6, wherein a cover is provided in front of the imaging device and the cover has a coating with the same optical characteristics as those of the optical filter.

11. The image processing system as claimed in claim 6, wherein the image processor processes an image captured in the infrared bandpass area to detect raindrops.

12. The image processing system as claimed in claim 6, wherein the image processor processes an image captured in the infrared cut area to detect a vehicle in front.

13. The image processing system as claimed in claim 6, wherein the image processor processes an image captured in the infrared cut area to detect a traffic lane.

14. The image processing system as claimed in claim 1, wherein the field of view of the imaging device is oriented downward from the horizontal direction.

15. The image processing system as claimed in claim 1, wherein the image processor processes an image captured by the imaging device to detect the amount of rainfall and controls a vehicle'"'"'s wiper or washer according to the detected amount of rainfall.

16. The image processing system as claimed in claim 15, wherein the wiper control function is disabled when it is detected that the vehicle'"'"'s selector lever is in the parking position.

17. The image processing system as claimed in claim 15, wherein a threshold for rainfall measurement which is used to control the wiper is changed depending on the vehicle velocity.

18. The image processing system as claimed in claim 15, wherein according to the detected amount of rainfall, wiper control is started upon elapse of a prescribed waiting time after the wiper is turned on.

19. The image processing system as claimed in claim 18, wherein at least either of the vehicle velocity and raindrop diameter is used to control the length of the waiting time.

20. The image processing system as claimed in claim 15, wherein the image processor detects fog on the inner surface of the glass according to reflected light originating in another lamp and, when there is no fog on the inner surface of the glass, controls the wiper or washer according to the detected amount of rainfall.

21. The image processing system as claimed in claim 15, wherein the torque of a motor for driving the wiper is measured and water repellency of the glass or wiper blade damage is evaluated according to the detected torque.

22. The image processing system as claimed in claim 15, wherein fog lamp control is done according to the detected amount of rainfall.

23. The image processing system as claimed in claim 15, wherein headlight high beam control is done according to the detected amount of rainfall.

24. The image processing system as claimed in claim 15, wherein a brightness of external light is measured and the wiper moving speed is varied according to the measured brightness.

25. The image processing system as claimed in claim 15, wherein at least either of the detected amount of rainfall and the detected raindrop diameter is used to control the time interval in intermittent movement of the wiper.

26. The image processing system as claimed in claim 15, wherein the time interval in intermittent movement of the wiper is controlled according to the vehicle velocity.

27. The image processing system as claimed in claim 1, wherein reflection brightness of light from the glass is measured and stain and/or raindrops are evaluated based on the measured brightness.

28. The image processing system as claimed in claim 27, wherein the wiper is activated when stain is detected, and after activation of the wiper, the washer is activated when stain is detected again in the same place.

29. The image processing system as claimed in claim 1, wherein a raindrop condition on the glass is detected and water repellency of the glass or wiper blade damage is evaluated according to the detected raindrop condition.

30. The image processing system as claimed in claim 1, wherein the lens which focuses on the point beyond the glass enables focusing of light which passes through the infrared wavelength transmitting area of the optical filter.

31. The image processing system as claimed in claim 1, wherein any focus of the lens is adjusted to the point beyond the glass to enable detection of the foreign matter on the glass.

32. An image processing system comprising:

a lamp

an imaging device which captures light which is emitted from the lamp and reflected by foreign matter on a glass;

an optical filter, located in front of the imaging device, a portion of the optical filter being an infrared wavelength transmitting area which transmits rays with an infrared wavelength of the reflected light;

an image processor which processes an image portion corresponding to the infrared wavelength transmitting area of the optical filter in an image captured by the imaging device and detects raindrops on the glass; and

a lens which is provided in front of the imaging device, the lens having a focus which is adjusted to a point beyond the glass to distinguish the foreign matter on the glass from objects that exist in front of the glass.

33. The image processing system as claimed in claim 32, wherein the lens is provided between the imaging device and the glass, and the image processor processes the image captured by the imaging device through the lens and detects raindrops.

34. The image processing system as claimed in claim 32, wherein the lens which focuses on the point beyond the glass enables focusing of light which passes through the infrared wavelength transmitting area of the optical filter.

35. The image processing system as claimed in claim 32, wherein any focus of the lens is adjusted to the point beyond the glass to enable detection of the raindrops on the glass.