Combined camera system

• US 5,308,960 A
• Filed: 05/26/1992
• Issued: 05/03/1994
• 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., Mulligan, Joseph P.
• Primary Examiner(s): PITTS, HAROLD I
• Application Number:
  US07/889,028
• Time in Patent Office: 707 Days
• Field of Search: 235/462, 235/472, 235/454
• US Class Current: 235/454
• 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. Upon detecting an acquisition target it decodes according to corresponding differing decoding algorithms. To facilitate this operation there is a system bus as well as a dedicated data bus for applying a scan signal of an optical scanning device to differing detection circuitry. 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. When detecting concentric rings the system of the present invention uses stored templates which represent a number of transformations of the target, for example, a number of magnifications. When the transformation of a target is determined, the corresponding stored template is correlated with the scan signal from the optical scanning device. To detect concentric rings the scan signal is applied to interleaving circuitry which correlates more than one scan at a time to provide constant throughput even though the stages of the detector operate at different speeds. 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. A system for continuously focusing an optical scanning device upon a plurality of optically readable labels passing by said scanning device, said plurality of optically readable labels being affixed to a plurality of packages of differing height positioned upon a continuously moving belt, comprising:

height sensing means for continuously sensing information representative of the height of each of said optically readable labels above said continuously moving belt to provide a distance signal representative of said sensed height; and

belt speed encoding means for providing a belt speed signal in accordance with the speed of said continuously moving belt; and

focusing means, responsive to said belt speed signal, for receiving said distance signal and continuously focusing said optical scanning device upon said optically readable labels in accordance with said distance signal.

2. The continuous focusing method of claim 1, wherein said focusing system has a scanning region and said plurality of optically readable labels pass through said scanning region, said focusing means further comprising means to focus said scanning device upon said plurality of optically readable labels while said plurality of packages pass through said scanning region.

3. The continuous focusing method of claim 2, including a background surface wherein said height sensing means is adapted to focus said optical scanning device upon said background surface before and after focusing said optical scanning device upon said plurality of optically readable labels.

4. The continuous focusing method of claim 3, said plurality of optically readable labels having leading and trailing object edges wherein said focusing means is adapted to refocus from said background surface to the surface of one of said plurality of optically readable labels when said leading object edge enters said scanning region and refocus from said optically readable label surface to said background surface when said trailing edge leaves said scanning region in accordance with said distance signal.

5. The continuous focusing method of claim 1, wherein said height sensing means comprises ultrasonic sensing means.

6. The continuous focusing method of claim 1, wherein said height sensing means comprises infrared sensing means.

7. The continuous focusing method of claim 1, further comprising means for delaying said continuous focusing a selected period of time after said continuous sensing.

8. The continuous focusing method of claim 7, wherein said delay means comprises variable delay means for delaying a variable period of time.

9. The continuous focusing method of claim 8, wherein said variable delay means is controlled in accordance with the speed of said moving belt.

10. A method for continuously focusing an optical scanning device upon a plurality of optically readable labels passing by said scanning device, said plurality of optically readable labels being affixed to a plurality of packages of differing height positioned upon a continuously moving belt, comprising the steps of:

(a) continuously sensing information representative of the height of each of said optically readable labels above said continuously moving belt to provide a distance signal representative of said sensed height information;

(b) providing a belt speed signal in accordance with the speed of said continuously moving belt; and

(c) continuously focusing said scanning device upon said optically readable labels in accordance with said belt speed signal and said distance signal.

11. The continuous focusing method of claim 10, further comprising the steps of:

(d) continuously moving said plurality of optically readable labels through a scanning region of said optical scanning device; and

,

(e) focusing said scanning device upon said plurality of optically readable labels when said plurality of optically readable labels pass through said scanning region.

12. The continuous focusing method of claim 11, wherein a background surface is provided, comprising the further step of focusing said optical scanning device upon said background surface before and after the step of focusing said scanning device upon said plurality of optically readable labels.

13. The continuous focusing method of claim 12, one of said optically readable labels having leading and trailing edges, further comprising the step of refocusing from said background surface to the surface of one of said plurality of optically readable labels when said leading object edge enters said scanning region and from said optically readable label surface to said background surface when said trailing edge leaves said scanning region in accordance with said distance signal.

14. The continuous focusing method of claim 10, comprising the further step of delaying said continuous focusing of step (c) a selected period of time after said continuous sensing of step (a).

15. The continuous focusing method of claim 14, further comprising the step of providing a variable delay time period.

16. The continuous focusing method of claim 15, further comprising the step of controlling said variable delay in accordance with the speed of said moving belt.