Wide angle imaging system

• US 6,922,292 B2
• Filed: 07/07/2003
• Issued: 07/26/2005
• Est. Priority Date: 07/27/1999
• Status: Expired due to Term

• Current Assignee: Donnelly Corporation (Magna International Incorporated)
• Original Assignee: Donnelly Corporation (Magna International Incorporated)
• Inventors: Bos, Brent J.
• Primary Examiner(s): Robinson, Mark A.
• Assistant Examiner(s): AMARI, ALESSANDRO V
• Application Number:
  US10/614,454
• Publication Number:
  US 20040021956A1
• Time in Patent Office: 750 Days
• Field of Search: 359/565, 359/742, 359/743, 359749-753, 348/113, 348/118, 348/148
• US Class Current: 359/753
• CPC Class Codes: B60R 1/00 Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
• CPC Class Codes: B60R 1/26 to the rear of the vehicle
• CPC Class Codes: B60R 2300/101 using cameras with adjustable capturing direction
• CPC Class Codes: B60R 2300/103 using camera systems provided with artificial illumination device, e.g. IR light source
• CPC Class Codes: B60R 2300/30 characterised by the type of image processing
• CPC Class Codes: B60R 2300/404 triggering from stand-by mode to operation mode
• CPC Class Codes: B60R 2300/802 for monitoring and displaying vehicle exterior blind spot views
• CPC Class Codes: B60R 2300/8066 for monitoring rearward traffic
• CPC Class Codes: G02B 13/06 Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces

Abstract

A wide angle imaging system for providing a wide angle field of view of an area exteriorly of a vehicle includes an image capture device having a field of view directed exteriorly of the vehicle, an outer wide angle lens, a focusing lens and a display. The image capture device may comprise an array of pixels and may have a coarse distribution of pixels and a fine distribution of pixels. The display may be operable to display a substantially undistorted image to the driver or occupant of the vehicle in response to a signal output of the image capture device.

Claims

1. A vehicular vision system comprising:

a wide angle lens group positionable on a portion of a vehicle for refracting a virtual image of an exterior view from the vehicle, thereby creating a wide angle refracted image, said wide angle lens group including an outer negative optic and an inner negative optic, said wide angle lens group comprising at least one of a polycarbonate and acrylic material;

a focusing lens group which receives said refracted image and focuses the refracted image onto an image plane;

an image capture device positioned on said image plane to receive the focused image from said focusing lens group, said wide angle lens group and said focusing lens group defining an optic path between an outer end of said wide angle lens group and said image capture device;

an image distortion correction process whereby an image captured by said vision system is processed to correct distortion therein, said image distortion correction process being at least partially provided by a plurality of refractive optics, said wide angle lens group including at least one wide angle diffractive element positioned along said optic path, said wide angle diffractive element correcting color focusing of the refracted virtual image; and

a display which displays a substantially non-distorted image of the scenic information, the non-distorted image being communicated from said image distortion process, wherein said wide angle diffractive element is on an outer surface of said inner negative optic, said wide angle diffractive element being defined by the equation;

Φ

=A₁ρ

²+A₂ρ

⁴

where ρ

is a radial uperture coordinate divided by 1 mm, A₁ is a constant within a range of approximately 15 to 55 and A₂ is a constant within a range of approximately −

0.01 to −

0.5.

2. The vehicular vision system of claim 1, wherein said focusing lens group includes a refractive and diffractive lens element positioned along said optic path.

3. The vehicular vision system of claim 1, wherein said focusing lens group is constructed of one of polycarbonate and acrylic.

4. The vehicular vision system of claim 1, wherein said focusing lens group includes at least one diffractive element positioned along said optic path, said diffractive element correcting color focusing of the refracted image.

5. The vehicular vision system of claim 1, wherein A₁ is approximately 47.4149 and A₂ is approximately −

0.1463.

6. The vehicular vision system of claim 1, wherein said outer surface of said inner negative optic has a radius of curvature in a range of approximately 20 mm to 60 mm.

7. The vehicular vision system of claim 6, wherein said outer surface of said inner negative optic has a radius of curvature of approximately 35.3824 mm.

8. The vehicular vision system of claim 6, wherein said inner negative optic has an inner aspheric surface opposite said outer wide angle diffractive element, said inner aspheric surface being defined by the following equation:

$z=\frac{c<br><br>\text{\hspace{1em}<br><br>}<br><br>y^2}{1+\sqrt{1-\left(1+K\right)<br><br>c^2<br><br>y^2}};<br><br>c=\frac{1}{r_{x<br><br>\text{\hspace{1em}<br><br>}<br><br>y}};<br><br>$

where x, y and z are coordinates on said inner aspheric surface along an x-axis, a y-axis and a z-axis, respectively, r_xy is a radius of curvature to each point on said inner aspheric surface corresponding to an x coordinate and a y coordinate, and K is a conic constant within a range of approximately −

1 to −

20.

9. The vehicular vision system of claim 8, wherein K is approximately −

13.3619.

10. The vehicular vision system of claim 8, wherein said outer negative optic has an outer surface and an inner surface, said outer surface of said outer negative optic having a radius of curvature of approximately 40 mm to 700 mm, said inner surface of said outer negative optic having a radius of curvature of approximately 20 mm to 40 mm, said inner surface of said outer negative optic being on a side toward said inner negative optic.

11. The vehicular vision system of claim 1, wherein said image distortion correction process is provided by said image capture device.

12. The vehicular vision system of claim 11, wherein said image capture device is a CMOS imaging array including a non-uniform array of pixels, said non-uniform array having a coarse distribution of said pixels in portions corresponding to the refracted image where there is minimal distortion and a fine distribution of said pixels in portions corresponding to the refracted image where there is greater distortion, the refracted image being received by said non-uniform pixels and communicated to a uniform array on said display, said display thereby receiving and displaying a uniform, substantially non-distorted image to the operator of the vehicle.

13. The vehicular vision system of claim 1, wherein said image distortion correction process is provided by electronic processing of the image received by said vision system.

14. The vehicular vision system of claim 1, wherein said outer negative optic comprises crown glass and said inner negative optic comprises one of polycarbonate and acrylic.

15. A vehicular vision system comprising:

an image capture device having a field of view, said image capture device comprising a pixelated imaging array having a non-uniform array of pixels;

a wide angle lens system disposed in front of said pixelated imaging array, said wide angle lens system including an outer negative optic and an inner negative optic, said wide angle lens system including at least one wide angle diffractive element, said at least one wide angle diffractive element correcting color focusing of the image;

at least one focusing lens disposed between said wide angle lens system and said pixelated imaging array, said wide angle lens system and said at least one focusing lens defining an optic path, said image capture device capturing an image exterior of the vehicle; and

a display, said display displaying a substantially non-distorted image in response to a signal output of said image capture device, wherein said wide angle diffractive element is on an outer surface of said inner negative optic, said wide angle diffractive element being defined by the equation;

σ

=A₁ρ

²+A₂ρ

⁴

where ρ

is a radial aperture coordinate divided by 1 mm, A₁ is a constant within a range of approximately 15 to 55 and A₂ is a constant within a range of approximately −

0.01 to −

0.5.

16. The vehicular imaging system of claim 15, wherein said non-uniform array of pixels has a coarse distribution of pixels in at least one portion of said non-uniform array corresponding to at least one portion of the image where there is minimal distortion.

17. The vehicular imaging system of claim 15, wherein said non-uniform array of pixels has a fine distribution of pixels in at least one portion of said non-uniform array corresponding to at least one portion of the image where there is greater distortion.

18. The vehicular imaging system of claim 15, wherein said non-uniform array of pixels has a coarse distribution of pixels in at least one portion of said non-uniform array corresponding to at least one portion of the image where there is minimal distortion and a fine distribution of pixels in at least one portion of said non-uniform array corresponding to as least one portion of the image where there is greater distortion.

19. The vehicular vision system of claim 15, wherein said image capture device comprises a CMOS imaging array.

20. The vehicular vision system of claim 15, wherein said wide angle lens system comprises at least one of a polycarbonate and acrylic material.

21. The vehicular vision system of claim 15, wherein said outer negative optic comprises crown glass and said inner negative optic comprises one of polycarbonate and acrylic.

22. The vehicular vision system of claim 15, wherein said at least one focusing lens is constructed of one of polycarbonate and acrylic.

23. The vehicular vision system of claim 15, wherein said at least one focusing lens includes a refractive lens element and a diffractive lens element.

24. The vehicular vision system of claim 15, wherein said at least one focusing lens includes at least one diffractive element, said at least one diffractive element correcting color focusing of the image.

25. The vehicular vision system of claim 24, wherein said wide angle lens system includes at least one wide angle diffractive element, said at least one wide angle diffractive element correcting color focusing of the image.

26. The vehicular vision system of claim 15, wherein said outer surface of said inner negative optic has a radius of curvature in a range of approximately 20 mm to 60 mm.

27. The vehicular vision system of claim 26, wherein said inner negative optic has an inner aspheric surface opposite outer angle diffractive element, said inner aspheric surface being defined by the following equation:

$z=\frac{c<br><br>\text{\hspace{1em}<br><br>}<br><br>y^2}{1+\sqrt{1-\left(1+K\right)<br><br>c^2<br><br>y^2}};<br><br>c=\frac{1}{r_{x<br><br>\text{\hspace{1em}<br><br>}<br><br>y}};<br><br>$

where x, y and z are coordinates on said inner aspheric surface along an x-axis, a y-axis and a z-axis, respectively, r_xy is a radius of curvature to each point on said inner aspheric surface corresponding to an x coordinate and a y coordinate, and K is a conic constant within a range of approximately −

1 to −

20.

28. The vehicular vision system of claim 27, wherein said outer negative optic has an outer surface and an inner surface, said outer surface of said outer negative optic having a radius of curvature of approximately 40 mm to 700 mm, said inner surface of said outer negative optic having a radius of curvature of approximately 20 mm to 40 mm, said inner surface of said outer negative optic being on a side toward said inner negative optic.

29. A vehicular vision system comprising:

an image capture device having a field of view, said image capture device comprising a pixelated imaging array having a non-uniform array of pixels, said non-uniform array of pixels comprising a coarse distribution of pixels in at least one portion of said non-uniform array of pixels and a fine distribution of pixels in at least one other portion or said non-uniform array of pixels, said image capture device capturing an image exterior of the vehicle;

at least one lens disposed in front of said pixelated imaging array, said at least one lens comprising a wide angle lens group including an outer negative optic and an inner negative optic, said wide angle lens group including at least one wide angle diffractive element, said at least one wide angle diffractive element correcting color focusing of the image; and

a display, said display displaying a substantially non-distorted image of the exterior scene to the operator of the vehicle in response to a signal output of said image capture device, wherein said wide angle diffractive element is on an outer surface of said inner negative optic, said wide angle diffractive element being defined by the equation;

σ

=A₁ρ

²+A₂ρ

⁴

where ρ

is a radial aperture coordinate divided by 1 mm, A₁ is a constant within a range of approximately 15 to 55 and A₂ is a constant within a range of approximately −

0.01 to −

0.5.

30. The vehicular imaging system of claim 29, wherein said non-uniform array of pixels has a coarse distribution of pixels in at least one portion of said non-uniform array of pixels corresponding to at least one portion of the image where there is minimal distortion.

31. The vehicular imaging system of claim 29, wherein said non-uniform array of pixels has a fine distribution of pixels in at least one other portion of said non-uniform array of pixels corresponding to at least one portion the image where there is greater distortion.

32. The vehicular imaging system of claim 29, wherein said non-uniform array of pixels has a coarse distribution of pixels in at least one portion of said non-uniform array of pixels corresponding to at least one portion of the image where there is minimal distortion and a fine distribution of pixels in at least one other portion of said non-uniform array of pixels corresponding to at least one portion the image where there is greater distortion.

33. The vehicular vision system of claim 29, wherein said image capture device comprises a CMOS imaging array.

34. The vehicular vision system of claim 29, wherein said at least one lens comprises at least one of a polycarbonate and acrylic material.

35. The vehicular vision system of claim 29, wherein said outer negative optic comprises crown glass and said inner negative optic comprises one of polycarbonate and acrylic.

36. The vehicular vision system of claim 29, wherein said outer surface of said inner negative optic has a radius of curvature in a range of approximately 20 mm to 60 nm.

37. The vehicular vision system of claim 36, wherein said inner negative optic has an inner aspheric surface opposite said outer wide angle diffractive element, said inner aspheric surface being defined by the following equation:

$z=\frac{c<br><br>\text{\hspace{1em}<br><br>}<br><br>y^2}{1+\sqrt{1-\left(1+K\right)<br><br>c^2<br><br>y^2}};<br><br>c=\frac{1}{r_{x<br><br>\text{\hspace{1em}<br><br>}<br><br>y}};<br><br>$

when x, y and z are coordinates on said inner aspheric surface along an x-axis, a y-axis and a z-axis, respectively, r_xy is a radius of curvature to each point on said inner aspheric surface corresponding to an x coordinate and a y coordinate, and K is a conic constant within a range of approximately −

1 to −

20.

38. The vehicular vision system of claim 37, wherein said outer negative optic has an outer surface and an inner surface, said outer surface of said outer negative optic having a radius of curvature of approximately 40 mm to 700 mm, said inner surface of said outer negative optic having a radius of curvature of approximately 20 mm to 40 mm, said inner surface of said outer negative optic being on a side toward said inner negative optic.

39. The vehicular vision system of claim 29, wherein said at least one lens includes at least one wide angle lens and at least one focusing lens, said at least one focusing lens being disposed between said at least one wide angle lens and said pixelated imaging array.

40. The vehicular vision system of claim 39, wherein said at least one focusing lens is constructed of one of polycarbonate and acrylic.

41. The vehicular vision system of claim 39, wherein said at least one focusing lens includes a refractive lens element and a diffractive lens element.

42. The vehicular vision system of claim 39, wherein said at least one focusing lens includes at least one diffractive element, said at least one diffractive element correcting color focusing of the image.

43. The vehicular vision system of claim 42, wherein said at least one wide angle lens includes at least one wide angle diffractive element, said at least one wide angle diffractive element correcting color focusing on the image.