Electronic imaging system and sensor for correcting the distortion in a wide-angle lens

• US 5,489,940 A
• Filed: 12/08/1994
• Issued: 02/06/1996
• Est. Priority Date: 12/08/1994
• Status: Expired due to Term

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Stuckman, Bruce E., Richardson, Charles P.
• Primary Examiner(s): GARBER, WENDY RAE
• Application Number:
  US08/352,307
• Time in Patent Office: 425 Days
• Field of Search: 348/335, 348/340, 348/294, 348/311, 348/315, 348/91, 348/342, 257/231
• US Class Current: 348/315
• CPC Class Codes: H04N 25/61 the noise originating only from the lens unit, e.g. flare, shading, vignetting or "cos4"
• CPC Class Codes: H04N 25/702 SSIS architectures characterised by non-identical, non-equidistant or non-planar pixel layout

Abstract

A wide-angle lens produces a distorted wide-angle optical image. An imaging sensor, having a surface in optical communication with the wide-angle lens, converts the wide-angle optical image into a corresponding output signal. The imaging sensor includes a plurality of imaging elements. The plurality of imaging elements have a distribution on the surface of the sensor that is representable by a nonlinear function, wherein the distribution of the imaging elements corrects the distortion in the wide-angle image.

Claims

1. An electronic imaging system for capturing a wide-angle image, the system comprising;

a wide-angle lens for producing a wide-angle optical image, the wide-angle lens producing a distortion in the wide-angle image; and

an imaging sensor, having a surface in optical communication with the wide-angle lens, for converting the wide-angle optical image into a corresponding output signal, the imaging sensor comprising a plurality of imaging elements, the plurality of imaging elements having a distribution on the surface representable by a nonlinear function;

wherein the distribution of the imaging elements corrects the distortion in the wide-angle image.

2. The system of claim 1 wherein each of the plurality of imaging elements includes a pixel of a charge-coupled device.

3. The system of claim 1 wherein the plurality of imaging elements are in a two-dimensional array.

4. The system of claim 3 wherein each of the plurality of imaging elements is electronically addressable by a two-dimensional address (a, b).

5. The system of claim 3 wherein the distribution of imaging elements has a relatively low density at a center point of the two-dimensional array and a relatively high density at a point along the periphery of the two-dimensional array.

6. The system of claim 5 wherein the nonlinear function can be represented by:

space="preserve" listing-type="equation">rho=rho.sub.0 (1-(rT/180R'"'"').sup.2).sup.-1/2

where r is a radial distance of a selected imaging element from the center point of the two-dimensional array, rho₀ is the density of the distribution of imaging elements, R'"'"' corresponds to a maximum radius r of the two-dimensional array and where T is the maximum angle captured by the wide-angle lens (in degrees).

7. The system of claim 1 wherein the output signal is a video signal.

8. The system of claim 1 wherein the output signal includes a plurality of image data.

9. The system of claim 1 further comprising a display, responsive to the output signal, for displaying the wide-angle image.

10. The system of claim 1 further comprising a image processing unit, responsive to the output signal and a user command signal, for selectively magnifying a first region of the wide-angle image.

11. The system of claim 10 further comprising a image processing unit, responsive to the output signal and a user command signal, for selectively panning from a second region of the wide-angle image to a third region of the wide-angle image.

12. The system of claim 10 further comprising a user interface device, coupled to the image processing unit, for generating the user command signal.

13. A sensor use in an electronic imaging system having a wide-angle lens that produces a wide-angle optical image having a distortion, the sensor comprising;

a surface in optical communication with the wide-angle lens; and

a plurality of imaging elements, coupled to the surface, for converting the wide-angle optical image into a corresponding output signal, the plurality of imaging elements having a distribution on the surface representable by a nonlinear function;

wherein the distribution of the imaging elements corrects the distortion in the wide-angle image.

14. The sensor of claim 13 wherein each of the plurality of imaging elements includes a pixel of a charge-coupled device.

15. The sensor of claim 13 wherein the plurality of imaging elements are in a two-dimensional array.

16. The sensor of claim 15 wherein each of the plurality of imaging elements is electronically addressable by a two-dimensional address (a, b).

17. The sensor of claim 15 wherein the distribution of imaging elements has a relatively low density at a center point of the two-dimensional array and a relatively high density at a point along the periphery of the two-dimensional array.

18. The sensor of claim 17 wherein the nonlinear function can be represented by:

space="preserve" listing-type="equation">rho=rho.sub.0 (1-(rT/180R'"'"').sup.2).sup.-1/2

where r is a radial distance of a selected imaging element from the center point of the two-dimensional array, rho₀ is the density of the distribution of imaging elements, R'"'"' corresponds to a maximum radius r of the two-dimensional array and where T is the maximum angle captured by the wide-angle lens (in degrees).

19. The sensor of claim 13 wherein the output signal is a video signal.

20. The sensor of claim 13 wherein the output signal includes a plurality of image data.