Image processing system

• US 20050035926A1
• Filed: 08/12/2004
• Published: 02/17/2005
• 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, Takenaga, Hiroshi, Monji, Tatsuhiko, Furusawa, Isao, Fukuhara, Masaaki, Ohsumi, Ken, Kasuya, Hiroyuki
• Granted Patent: US 7,208,723 B2
• Time in Patent Office: Days
• US Class Current: 345/8
• 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 which detects foreign matter on window of a vehicle with high reliability. The system includes an image processor, a first lamp, and a second lamp and when to turn on the first and second lamps is controlled by the image processor. Light from the first lamp passes through the glass. If there are raindrops on the outer surface of the glass, light is reflected by raindrops and light from the second lamp is reflected by a surface of the glass and such reflected light goes through a lens and an optical filter with prescribed optical characteristics to an imaging device.

Claims

1. An image processing system comprising:

a first lamp which emits light to glass;

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

an optical filter, located between the glass and the imaging device, which transmits rays with a specific wavelength of the reflected light; and

an image processor which processes an image captured by the imaging device.

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 vehicle'"'"'s windshield;

a second lamp for emitting light to the glass is provided;

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

the optical filter transmits such light that has longer wavelengths than visible light and is detected by the imaging device.

5. The image processing system as claimed in claim 4, wherein the second lamp is located on a dashboard near a driver'"'"'s seat in a vehicle.

6. The image processing system as claimed in claim 4, wherein the image processor detects raindrops on the outer surface of the glass according to light emitted from the first lamp and detects fog on the inner surface of the glass according to light emitted from the second lamp.

7. The image processing system as claimed in claim 4, wherein a lens is provided in front of the imaging device and the focus of the lens is adjusted to a point beyond the glass.

8. The image processing system as claimed in claim 4, wherein the image processor, the first lamp and the second lamp are housed in a case and a vent is provided between the case and the glass.

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

10. The image processing system as claimed in claim 4, wherein the optical filter has areas with different optical characteristics.

11. The image processing system as claimed in claim 10, 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.

12. The image processing system as claimed in claim 11, 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.

13. The image processing system as claimed in claim 11, wherein the upper area of the optical filter constitutes the infrared bandpass area and the lower area constitutes the infrared cut area when the optical filter is located between the glass and the imaging device.

14. The image processing system as claimed in claim 11, wherein a lens is provided in front of the imaging device and the lens has a coating with the same optical characteristics as those of the optical filter.

15. The image processing system as claimed in claim 11, 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.

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

17. The image processing system as claimed in claim 11, wherein the image processor processes an image captured in the infrared cut area to detect a vehicle in front.

18. The image processing system as claimed in claim 11, wherein the image processor processes an image captured in the infrared cut area to detect a traffic lane.

19. The image processing system as claimed in claim 4, wherein the field of view of the imaging device is oriented downward from the horizontal direction.

20. The image processing system as claimed in claim 4, 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.

21. The image processing system as claimed in claim 20, wherein the wiper control function is disabled when it is detected that the vehicle'"'"'s selector lever is in the parking position.

22. The image processing system as claimed in claim 20, wherein a threshold for rainfall measurement which is used to control the wiper is changed depending on the vehicle velocity.

23. The image processing system as claimed in claim 20, 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.

24. The image processing system as claimed in claim 23, wherein at least either of the vehicle velocity and raindrop diameter is used to control the length of the waiting time.

25. The image processing system as claimed in claim 20, wherein the image processor detects fog on the inner surface of the glass according to reflected light originating in the second 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.

26. The image processing system as claimed in claim 20, 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.

27. The image processing system as claimed in claim 20, wherein fog lamp control is done according to the detected amount of rainfall.

28. The image processing system as claimed in claim 20, wherein headlight high beam control is done according to the detected amount of rainfall.

29. The image processing system as claimed in claim 20, wherein the brightness of external light is measured and the wiper moving speed is varied according to the measured brightness.

30. The image processing system as claimed in claim 20, 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.

31. The image processing system as claimed in claim 20, wherein the time interval in intermittent movement of the wiper is controlled according to the vehicle velocity.

32. The image processing system as claimed in claim 4, wherein the reflection brightness of light from the glass is measured and stain and/or raindrops are evaluated based on the measured brightness.

33. The image processing system as claimed in claim 32, 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.

34. The image processing system as claimed in claim 4, wherein the 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.

35. The image processing system as claimed in claim 4, wherein a mirror is provided, and after light emitted from the second lamp is reflected by the glass, it is reflected by the mirror and again reflected by the glass before reaching the imaging device.

41. The image processing system as claimed in claim 1, wherein the optical filter transmits light with wavelengths in a wavelength range in which the transmittance of the glass is above a prescribed level and the photosensitivity of the imaging device is high enough.

42. The image processing system as claimed in claim 41, wherein the optical filter transmits light with wavelengths in the visible light range.

36. An image processing system comprising:

a light source in the form of an array of light emitters;

a light source controller which turns on the plural light emitters;

an imaging device which captures light which is emitted from the light source and reflected by fog on the glass; and

an image processor which processes an image captured by the imaging device,

wherein the image processor processes the image and measures at least either of the extent of fog on the glass, the direction of fog spread, and the speed of fog spread on the glass.

37. An image processing system comprising:

a light source;

an imaging device which captures light which is emitted from the light source and reflected by fog on the glass; and

an image processor which processes an image captured by the imaging device,

wherein an area of the glass surface in which light from the light source is reflected by the fog to be captured by the imaging device is designed to become foggy easily.

38. The image processing system as claimed in claim 37, wherein the image processor processes the image captured by the imaging device to detect fog on the glass and, upon detection of fog, activates a defroster.

39. The image processing system as claimed in claim 37, wherein the area is frosted glass.

40. The image processing system as claimed in claim 37, wherein the area is water-repellent finished.