Camera system optics

• US 5,327,171 A
• Filed: 05/26/1992
• Issued: 07/05/1994
• Est. Priority Date: 05/26/1992
• Status: Expired due to Term

• Current Assignee: United Parcel Service Of America Incorporated (United Parcel Service Incorporated)
• Original Assignee: United Parcel Service Of America Incorporated (United Parcel Service Incorporated)
• Inventors: Smith, Steven L., Skinger, Gregory P., Esslinger, Robert H., Mulligan, Joseph P.
• Primary Examiner(s): Mancuso, Joseph
• Assistant Examiner(s): Greening, Wendy R.
• Application Number:
  US07/889,037
• Time in Patent Office: 770 Days
• Field of Search: 358/213.15, 358/101, 358/486, 358/228, 358/170, 348/223, 348/241
• US Class Current: 348/223.1
• CPC Class Codes: G06K 2007/10485 Arrangement of optical elements
• CPC Class Codes: G06K 2207/1013 Multi-focal
• CPC Class Codes: G06K 7/10851 Circuits for pulse shaping, amplifying, eliminating noise signals, checking the function of the sensing device basic electronic circuitry H03
• CPC Class Codes: G06K 7/1092 sensing by means of TV-scanning
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1443 locating of the code in an image

Abstract

The camera system of the present invention simultaneously searches for a number of differing optical acquisition targets. This system may decode, for example, both bar codes and concentric rings. The scan signal is constantly adjusted according to both a dark reference for correcting offset and a white reference for correcting gain. The gain is also corrected according to the scanning rate as well as the amount of illumination present. A measure of this illumination may be applied directly to the optical scanning device by way of a fiber optic cable which transmits light from the illumination source. Optical calibration is eliminated by fixed optics wherein all optical elements are rigidly mounted at very close tolerances. The illumination source is disposed on one focus of an ellipse wherein the other focus is disposed at the maximum scanning distance and the reflector is formed to define the illumination ellipse to maximize the light applied to the object. The various heat producing elements are disposed in sealed compartments which are cooled by forced air which is circulated through a heat exchanger. A real time focusing system is provided wherein the distance from the scanning device to an opposing surface is constantly monitored and the system is constantly focused according to the distance.

Claims

1. An optical object scanning system having an optical scanning device for providing a scan output signal including a scan output information portion representative of a scanned region of said object, said scan output information portion having a varying information amplitude, comprising:

illumination source means for illuminating said scanned region of said object;

detection means for receiving light reflected from said scanned region of said object;

white reference means for providing a white reference signal, said white reference means including at least one dedicated pixel for receiving light transmitted from said illumination source means, said at least one dedicated pixel being unavailable for receiving said reflected light from said scanned region of said object; and

adjusting means for adjusting said varying information amplitude of said scan output information portion in accordance with said white reference signal.

2. The optical scanning system of claim 1, further comprising means for providing a plurality of said white reference signals.

3. The optical scanning system of claim 2, wherein said optical scanning device has scan cycles further comprising means for providing at least one of said plurality of white reference signals for each of said scan cycles.

4. The optical scanning system of claim 2, wherein said adjusting means comprises means for adjusting said information amplitude in accordance with said plurality of white reference signals.

5. The optical scanning system of claim 4, wherein said optical scanning device has scan cycles and wherein said adjusting means comprises means for adjusting said information amplitude for each of said scan cycles.

6. The optical scanning system of claim 2, wherein said adjusting means comprises integration means for providing an integration signal in accordance with said plurality of white reference signals.

7. The optical scanning system of claim 6, wherein said adjusting means further comprises white reference feedback means for adjusting said information amplitude in accordance with said integration signal.

8. The optical scanning device of claim 7, further comprising means for updating said integration signal and adjusting said information amplitude every scan cycle of said optical scanning device in accordance with said integration signal.

9. The optical scanning system of claim 1, wherein said object moves at varying object speeds further comprising means for providing said white reference signal in accordance with said varying object speeds.

10. The optical scanning system of claim 9, wherein said amplitude adjusting means comprises integrator means for providing an integration signal representative of said varying object speeds.

11. The optical scanning system of claim 1, further comprising:

light transmitting means for transmitting light from said illumination source means; and

,

said white reference means including means for receiving said transmitted light and providing said white reference signal in accordance with said transmitted light.

12. The optical scanning system of claim 11, wherein said light transmitting means comprises means for transmitting light to said optical scanning device.

13. The optical scanning system of claim 11, including a plurality of illumination sources each having corresponding light transmitting means, further comprising respective illumination adjusting means for adjusting each illumination source in accordance with its corresponding transmitted light.

14. An optical scanning method in a system including an optical scanning device having scan cycles with an optical scanning rate for providing a scan output signal including a scan output information component having a varying information amplitude representative of light received by said optical scanning device, comprising the steps of:

(a) illuminating a region of an object with illumination source means;

(b) receiving light reflected from said region of said object with detection means;

(c) providing a varying white reference signal with white reference means, said white reference means including at least one dedicated pixel for receiving light transmitted from said illumination source means, said at least one dedicated pixel being unavailable for receiving said reflected light from said region of said object; and

,

(d) adjusting said varying information amplitude of said scan output information component in accordance with said white reference signal.

15. The optical scanning method of claim 14, comprising the further step of providing a plurality of said white reference signals.

16. The optical scanning method of claim 15, further comprising the step of providing at least one of said plurality of white reference signals for each scan cycle of said optical scanning device.

17. The optical scanning method of claim 15, wherein step (d) comprises the step of adjusting said information amplitude in accordance with said plurality of said white reference signals.

18. The optical scanning method of claim 17, further comprising the step of adjusting said information amplitude each scan cycle of said optical scanning device.

19. The optical scanning method of claim 16, wherein step (d) further comprises integrating by integrator means for providing an integration signal in accordance with said plurality of white reference signals and adjusting said information amplitude in accordance with said integration signal.

20. The optical scanning method of claim 19, further comprising the step of updating said integration signal and adjusting said information amplitude in accordance with said updated integration signal every scan cycle of said optical scanning device.

21. The optical scanning method of claim 14, comprising the further steps of:

(e) moving said object past said optical scanning device at varying object speeds;

(f) providing a velocity signal representative of said varying object speeds; and

,

(g) providing said varying white reference signal in accordance with said varying object speeds.

22. The optical scanning method of claim 21, wherein step (d) comprises adjusting means in accordance with integrator means for providing an integration output signal representative of said varying object speeds.