Method and system for improving camera infrared sensitivity using digital zoom

• US 6,420,704 B1
• Filed: 12/07/2000
• Issued: 07/16/2002
• Est. Priority Date: 12/07/2000
• Status: Expired due to Fees

• Current Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: TRW Limited (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Dunbridge, Barry, McIver, George W., Berenz, John J.
• Primary Examiner(s): Hannaher, Constantine
• Assistant Examiner(s): Israel, Andrew
• Application Number:
  US09/732,429
• Publication Number:
  US 20020070342A1
• Time in Patent Office: 586 Days
• Field of Search: 250/330, 250/332, 250/334, 250/338.1, 250/201.2, 250/221
• US Class Current: 250/330
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A system for providing recognition of an approaching object located in a distant no-light environment includes an illumination source for transmitting light to the distant object and an imaging device for detecting the light radiation reflected from the distant object to generate an image of the distant object corresponding thereto. The system also includes an independent digital signal processor for calculating a desired optical magnification of a lens of the imaging device as a function of a distance between the imaging device and the distant object and generates a voltage corresponding thereto. The digital signal processor applies the voltage to the digital zoom circuitry of the imaging device to adjust the magnification of the lens so that the image of the distant object is held in a fixed dimension.

Claims

1. A system for providing recognition of a distant object, comprising:

an illumination source for transmitting light radiation to the distant object;

an imaging device having a detector element including a plurality of pixel elements and a lens, the lens detecting the light radiation reflected from the distant object to generate an image of the object corresponding thereto; and

a digital signal processor element electrically connected with the imaging device, the digital signal processor element dynamically calculating a desired optical magnification of the lens as a function of a distance between the imaging device and the distant object, generating a voltage corresponding to the desired optical magnification and applying the voltage to the imaging device to adjust a magnification of the lens wherein the magnification adjustment is applied to each pixel element within a field of view of the detector element so that the image of the distant object is held in a fixed dimension for a predetermined period of time sufficient to capture the reflected light radiation.

2. A system as recited in claim 1, wherein the illumination source is an infrared light emitting diode.

3. A system as recited in claim 1, wherein the illumination source is a high frequency modulated illumination source.

4. A system as recited in claim 1, wherein the imaging device is a photoelectric image detector device.

5. A system as recited in claim 4, wherein the photoelectric image detector device is a near infrared sensitive photoelectric image detector device.

6. A system as recited in claim 5, wherein the near infrared sensitive photoelectric image detector device is a charge coupled device (CCD) camera.

7. A system as recited in claim 5, wherein the near infrared sensitive photoelectric image detector device is a complementary metal-oxide-semiconductor (CMOS) camera.

8. A system as recited in claim 1, wherein the lens is a digital zoom lens.

9. A system as recited in claim 8, wherein the digital zoom lens is a programmable digital zoom lens.

10. A system as recited in claim 1, wherein the digital signal processor element is a digital signal processing (DSP) chip.

11. A system as recited in claim 1, wherein the digital signal processor element comprises an arithmetic logic circuit programmed to determine the desired optical magnification as a function of the distance between the imaging device and the object.

12. A system as recited in claim 1, wherein the detector element is a charge coupled device (CCD) chip.

13. A method for providing recognition of a distant object, comprising:

transmitting light radiation to the distant object;

detecting the light radiation reflected from the distant object at an imager device having a lens;

calculating a desired optical magnification of the lens as a function of a distance between the imager device and the distant object;

generating a voltage corresponding to the desired optical magnification of the lens; and

applying the voltage to the imager device to adjust a magnification of the lens to the desired optical magnification so that an image of the object is held in a fixed dimension for a predetermined period of time.

14. The method as recited in claim 13, wherein transmitting light radiation to the distant object comprises transmitting infrared light to the distant object.

15. The method as recited in claim 13, wherein detecting the light radiation reflected from the distant object at the imager device comprises detecting the light radiation reflected from the distant object at a photoelectric image detector device.

16. The method as recited in claim 15, wherein detecting the light radiation reflected from the distant object at the photoelectric image detector device comprises detecting the light radiation reflected from the distant object at a near infrared sensitive photoelectric image detector device.

17. The method as recited in claim 16, wherein detecting the light radiation reflected from the distant object at the near infrared sensitive photoelectric image detector device comprises detecting the light radiation reflected from the distant object at a CCD camera.

18. The method as recited in claim 16, wherein detecting the light radiation reflected from the distant object at the near infrared sensitive photoelectric image detector device comprises detecting the light radiation reflected from the distant object at a CMOS camera.

19. The method as recited in claim 16, wherein detecting the light radiation reflected from the distant object at the imager device having the lens comprises detecting the light radiation reflected from the distant object at the imager device having a digital zoom lens.

20. The method as recited in claim 13, wherein calculating the desired optical magnification of the lens comprises:

calculating a distance between the imaging device and the distant object; and

determining the desired optical magnification as a function of the distance between the imaging device and the distant object.