Vehicle headlight control using imaging sensor with spectral filtering

• US 7,402,786 B2
• Filed: 10/06/2006
• Issued: 07/22/2008
• Est. Priority Date: 02/26/1993
• Status: Expired due to Fees

• Current Assignee: Magna Electronics Incorporated (Magna International Incorporated)
• Original Assignee: Donnelly Corporation (Magna International Incorporated)
• Inventors: Schofield, Kenneth, Larson, Mark L, Vadas, Keith J
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US11/545,039
• Publication Number:
  US 20070023613A1
• Time in Patent Office: 655 Days
• Field of Search: 250/205, 250/208.1, 250/214.R, 250/221, 250/559.4, 250/214.AL, 250/226, 359601-610, 359264-272, 180167-169, 340/426.23, 340/436
• US Class Current: 250/205
• CPC Class Codes: B60Q 1/1423 Automatic dimming circuits, i.e. switching between high beam and low beam due to change of ambient light or light level in road traffic
• CPC Class Codes: B60Q 2300/054 Variable non-standard intensity, i.e. emission of various beam intensities different from standard intensities, e.g. continuous or stepped transitions of intensity
• CPC Class Codes: B60Q 2300/056 Special anti-blinding beams, e.g. a standard beam is chopped or moved in order not to blind
• CPC Class Codes: B60Q 2300/21 Manual control
• CPC Class Codes: B60Q 2300/312 Adverse weather
• CPC Class Codes: B60Q 2300/314 Ambient light
• CPC Class Codes: B60Q 2300/41 preceding vehicle
• CPC Class Codes: B60Q 2300/42 oncoming vehicle
• CPC Class Codes: B60R 2001/1223 with sensors or transducers
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• CPC Class Codes: B60S 1/0844 including a camera
• CPC Class Codes: B60S 1/087 including an ambient light sensor control of vehicle lights B60Q
• CPC Class Codes: G01J 1/0488 with spectral filtering
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01J 3/51 using colour filters
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle

Abstract

A vehicle headlamp control method and apparatus includes providing an imaging sensor that senses light in spatially separated regions of a field of view forward of the vehicle. Light levels sensed in individual regions of the field of view are evaluated in order to identify light sources of interest, such as oncoming headlights and leading taillights. The vehicle'"'"'s headlights are controlled in response to identifying such particular light sources or absence of such light sources. Spectral signatures of light sources may be examined in order to determine if the spectral signature matches that of particular light sources such as the spectral signatures of headlights or taillights. Sensed light levels may also be evaluated for their spatial distribution in order to identify light sources of interest.

Claims

1. A control system for automatically controlling the state of the headlamps of a controlled vehicle, said control system comprising:

an optical system for imaging external light emitting sources within a predetermined field of view, said optical system including an image array sensor, said image array sensor comprising a pixelated imaging array;

said pixelated imaging array comprising a plurality of light-sensing pixels arranged on a semiconductor substrate;

said optical system further comprising a first spectral filter for passing visible light that is within a first spectral region that generally corresponds with the visible light spectral signature of a taillight of a vehicle, said first spectral filter substantially attenuating light having a wavelength greater than about 830 nanometers;

said optical system imaging visible light passing via said first spectral filter onto a first array portion of said pixelated imaging array;

said optical system imaging visible light passing via a second spectral filter onto a second array portion of said pixelated imaging array; and

an image processing system for processing images from said optical system and for providing a control signal for controlling the state of headlamps of the controlled vehicle as a function of the output of at least one pixel sensing light passing via said first spectral filter and the output of another at least one pixel sensing light passing via said second spectral filter.

2. The control system of claim 1, wherein at least one of (a) said second spectral filter encompasses at least a spectral portion of said first spectral filter, (b) said first spectral filter passes light having a wavelength longer than about 520 nm defining a red filter for imaging taillights on said first array portion of said pixelated imaging array, (c) said second spectral filter passes light having a wavelength shorter than about 620 nm for imaging headlamps on said second array portion of said pixelated imaging array, (d) said first spectral filter comprises a red filter that passes visible light of wavelength generally in the visible red spectral band and that substantially attenuates light having wavelengths outside the visible red spectral band, (e) said second spectral filter comprises a blue filter that passes visible light of wavelength generally in the visible blue spectral band and that substantially attenuates light having wavelengths outside the visible blue spectral band, (f) said second spectral filter comprises a blue filter that passes light having wavelengths representative of blue light and substantially attenuates electromagnetic energy having wavelengths greater than about 500 nanometers and less than about 400 nanometers, (g) said second spectral filter comprises a red complement filter that substantially attenuates wavelengths outside the visible red complement spectral band, (h) said second spectral filter comprises a red complement filter that substantially attenuates wavelengths outside the visible red complement spectral band and wherein said red complement filter substantially attenuates electromagnetic energy having wavelengths greater than about 640 nanometers and less than about 400 nanometers, (i) said second spectral filter comprises a green filter that passes visible light of wavelength generally in the visible green band and that substantially attenuates light having wavelengths outside the visible green band, and (j) said second spectral filter comprises a green filter that passes visible light of wavelength generally in the visible green band and that substantially attenuates light having wavelengths outside the visible green band and wherein said green filter passes light having wavelengths representative of green light and substantially attenuates electromagnetic energy having wavelengths greater than about 600 nanometers and less than about 450 nanometers.

3. The control system of claim 1, wherein at least one of (a) said optical system comprises at least one lens, (b) said optical system comprises at least one lens and wherein said at least one lens comprises a first lens and a second lens arranged to image said predetermined field of view onto respective ones of said first and second array portions of said pixelated imaging array, and (c) said optical system comprises at least one lens and wherein light passing through said first lens and said first spectral filter reaches said first array portion.

4. The control system of claim 1, wherein at least one of (a) each of said first and second array portions of said pixelated imaging array comprises an array of contiguous pixels, (b) at least one of said first spectral filter and said second spectral filter comprises a mosaic spectral filter, (c) each of said first spectral filter and said second spectral filter comprises a homogeneous composition for passing light within a predetermined spectral region onto the respective array portion of said pixelated imaging array and (d) said pixelated imaging array comprises a CMOS pixelated imaging array.

5. The control system of claim 1, wherein at least one of (a) said control system is operable to image the external light emitting sources at different exposure rates, thereby increasing the distinction between headlamps and taillights, (b) said image processing system processes images in a frame-by-frame manner and (c) said image processing system compares a frame to a successor frame to detect motion of said light sources relative to the controlled vehicle.

6. A control system for automatically controlling the state of the headlamps of a controlled vehicle, said control system comprising:

an optical system for imaging external light emitting sources within a predetermined field of view, said optical system including an image array sensor, said image array sensor comprising a CMOS pixelated imaging array;

said pixelated imaging array comprising a plurality of light-sensing pixels arranged on a substantially planar semiconductor substrate;

said optical system further comprising a first spectral filter for passing visible light that is within a first spectral region that generally corresponds with the visible light spectral signature of a taillight of a vehicle, said first spectral filter substantially attenuating light having a wavelength greater than about 830 nanometers;

said optical system imaging visible light passing via said first spectral filter onto a first predetermined array portion of said pixelated imaging array;

said optical system imaging visible light passing via a second spectral filter onto a second predetermined array portion of said pixelated imaging array;

wherein each of said first and second predetermined array portions of said pixelated imaging comprises a respective predetermined array portion of contiguous pixels; and

an image processing system for processing images from said optical system and for providing a control signal for controlling the state of headlamps of the controlled vehicle as a function of the output of at least one pixel sensing light passing via said first spectral filter and the output of another at least one pixel sensing light passing via said second spectral filter.

7. The control system of claim 6, wherein at least one of (a) said second spectral filter encompasses at least a spectral portion of said first spectral filter, (b) said second spectral filter encompasses at least a spectral portion of said first spectral filter and wherein said first spectral filter comprises a red filter that passes visible light of wavelength generally in the visible red spectral band and that substantially attenuates light having wavelengths outside the visible red spectral band, (c) said second spectral filter comprises a blue filter that passes visible light of wavelength generally in the visible blue spectral band and that substantially attenuates light having wavelengths outside the visible blue spectral band and (d) said optical system comprises a first lens and a second lens arranged to image said predetermined field of view onto respective ones of said first and second array portions of said pixelated imaging array and wherein light passing through said first lens and said first spectral filter reaches said first array portion.

8. The control system of claim 6, wherein said optical system comprises a first lens and a second lens arranged to image said predetermined field of view onto respective ones of said first and second array portions of said pixelated imaging array, wherein light passing through said first lens and said first spectral filter reaches said first array portion, and wherein said first lens and said first spectral filter pass light having a wavelength longer than about 520 nm defining a red filter for imaging taillights on said first array portion of said pixelated imaging array and wherein said second lens and said second spectral filter pass light having a wavelength shorter than about 620 nm for imaging headlamps on said second array portion of said pixelated imaging array.

9. The control system of claim 6, wherein at least one of (a) said control system is operable to image the external light emitting sources at different exposure rates and (b) said image processing system compares a frame to a successor frame to detect motion of said light sources relative to the controlled vehicle.

10. A control system for automatically controlling the state of the headlamps of a controlled vehicle, said control system comprising:

an optical system for imaging external light emitting sources within a predetermined field of view, said optical system including an image array sensor, said image array sensor comprising a pixelated imaging array;

said pixelated imaging array comprising a plurality of light-sensing pixels arranged on a semiconductor substrate;

said optical system further comprising a first spectral filter for passing visible light that is within a first spectral region that generally corresponds with the visible light spectral signature of a taillight of a vehicle, said first spectral filter substantially attenuating light having a wavelength greater than about 830 nanometers;

said optical system imaging visible light passing via a first lens and said first spectral filter onto a first predetermined array portion of said pixelated imaging array;

said optical system imaging visible light passing via a second lens and a second spectral filter onto a second predetermined array portion of said pixelated imaging array; and

an image processing system for processing images from said optical system and for providing a control signal for controlling the state of headlamps of the controlled vehicle as a function of the output of at least one pixel sensing light passing via said first lens and said first spectral filter and the output of another at least one pixel sensing light passing via said second lens and said second spectral filter.

11. The control system of claim 10, wherein at least one of (a) said second spectral filter encompasses at least a spectral portion of said first spectral filter, (b) said first spectral filter comprises a red filter that passes visible light of wavelength generally in the visible red spectral band and that substantially attenuates light having wavelengths outside the visible red spectral band and (c) said first spectral filter comprises a red filter that passes visible light of wavelength generally in the visible red spectral band and that substantially attenuates light having wavelengths outside the visible red spectral band and wherein said second spectral filter comprises a blue filter that passes visible light of wavelength generally in the visible blue spectral band and that substantially attenuates light having wavelengths outside the visible blue spectral band.

12. The control system of claim 10, wherein at least one of (a) each of said first and second array portions of said pixelated imaging array comprises an array of contiguous pixels and (b) at least one of said first spectral filter and said second spectral filter comprises a mosaic spectral filter.

13. The control system of claim 10, wherein said pixelated imaging array comprises a CMOS pixelated imaging array and wherein at least one of (a) said control system is operable to image the external light emitting sources at different exposure rates, thereby increasing the distinction between headlamps and taillights, (b) said image processing system compares a frame to a successor frame to detect motion of said light sources relative to the controlled vehicle, (c) said first lens and said first spectral filter pass light having a wavelength longer than about 520 nm defining a red filter for imaging tail lights on said first predetermined array portion of said pixelated imaging array, and (d) said first lens and said first spectral filter pass light having a wavelength longer than about 520 nm defining a red filter for imaging tail lights on said first predetermined array portion of said pixelated imaging array and wherein said second lens and said second spectral filter pass light having a wavelength shorter than about 620 nm for imaging headlamps on said second predetermined array portion of said pixelated imaging array.

14. A control system for automatically controlling the state of the headlamps of a controlled vehicle, said control system comprising:

an optical system for imaging objects external of the vehicle within a predetermined field of view, said optical system including an image array sensor, said image array sensor comprising a CMOS pixelated imaging array;

said pixelated imaging array comprising a plurality of light-sensing pixels arranged on a semiconductor substrate;

said optical system further comprising a first spectral filter for passing visible light that is within a first spectral region that generally corresponds with the visible light spectral signature of a taillight of a vehicle, said first spectral filter substantially attenuating light having a wavelength greater than about 830 nanometers;

said optical system imaging visible light passing via said first spectral filter onto a first array portion of said pixelated imaging array;

said optical system imaging visible light not passing through said first spectral filter onto a second array portion of said pixelated imaging array;

an image processing system for processing images from said optical system and for providing a control signal for controlling the state of headlamps of the controlled vehicle as a function of an output of said pixelated imaging array; and

wherein said control system is operable to image external light emitting sources at different exposure rates, thereby increasing the distinction between headlamps and taillights.

15. The control system of claim 14, wherein said image processing system compares a frame to a successor frame to detect an object of interest.

16. A control system for automatically controlling the state of the headlamps of a controlled vehicle, said control system comprising:

an optical system for imaging objects external of the vehicle within a predetermined field of view, said optical system including an image array sensor, said image array sensor comprising a pixelated imaging array;

said pixelated imaging array comprising a plurality of light-sensing pixels arranged on a substantially planar semiconductor substrate;

said optical system comprising a first spectral filter, wherein said first spectral filter comprises a red filter that passes visible light of wavelength generally in the visible red spectral band and that substantially attenuates light having wavelengths outside the visible red spectral band;

said optical system imaging visible light passing via said first spectral filter onto a first array portion of said pixelated imaging array and said optical system imaging visible light not passing through said first spectral filter onto a second array portion of said pixelated imaging array; and

an image processing system for processing images from said optical system, said image processing system comparing a frame to a successor frame to detect an object of interest, said image processing system providing a control signal for controlling the state of headlamps of the controlled vehicle.

17. The control system of claim 16, wherein said optical system images visible light not passing through said first spectral filter by imaging visible light passing via a second spectral filter onto a second array portion of said pixelated imaging array.

18. The control system of claim 16, wherein an analog-to-digital converter is commonly established with said pixelated imaging array on said semiconductor substrate and wherein said analog-to-digital converter connects to said pixelated imaging array, and wherein said image processing system determines a brightness of objects imaged within the predetermined field of view and wherein said brightness is determined at least by (a) an output of said analog-to-digital converter, (b) a computing of an average pixel intensity of pixels imaging the object of interest and (c) a computing of an average pixel intensity for objects imaged compared to a computed average pixel intensity for the pixelated imaging array.

19. The control system of claim 16, wherein said object of interest comprises a light source and wherein said image processing system compares a frame to a successor frame to detect motion of said light source relative to the controlled vehicle.

20. The control system of claim 16, wherein said comparing of frames comprises identifying a pixel grouping having a particular intensity in order to identify the object of interest.

21. The control system of claim 20, including pattern recognition.

22. The control system of claim 16, wherein identified objects of interest are compared over successive frames.

23. The control system of claim 22, wherein said image processing system provides a further control signal for at least one (a) providing a lane change warning to the driver of the controlled vehicle and (b) a traffic sign recognition.

24. The control system of claim 16, wherein said image array sensor comprises a CMOS pixelated imaging array.

25. The control system of claim 16, wherein said optical system comprises at least one lens and wherein said optical system is disposed behind a vehicle windshield and viewing therethrough, and wherein said optical system has a principle axis aimed forward of the vehicle and wherein the aim of said optical system is directed towards a region forward of the vehicle where objects of interest are expected to be present.