Method and apparatus for providing omnidirectional lighting in a scanning device

• US 8,740,078 B2
• Filed: 09/20/2012
• Issued: 06/03/2014
• Est. Priority Date: 10/24/2003
• Status: Expired due to Fees

• Current Assignee: Cognex Technology & Investment Corporation (Cognex Corporation)
• Original Assignee: Cognex Technology & Investment Corporation (Cognex Corporation)
• Inventors: Gerst, Carl W. III, Equitz, William H., Testa, Justin, Nadabar, Sateesha
• Primary Examiner(s): TRAIL, ALLYSON NEEL
• Application Number:
  US13/623,344
• Publication Number:
  US 20130233926A1
• Time in Patent Office: 621 Days
• Field of Search: 235/455, 235/462.42, 235/462.01, 235/462.45
• US Class Current: 235/455
• CPC Class Codes: G06K 7/10732 Light sources
• 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 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/146 the method including quality enhancement steps

Abstract

Systems and methods are provided for selectively controlling the illumination, and particularly dark field illumination, applied to a symbol to be decoded, and for determining a suitable or optimized level of lighting for decoding the symbol. A method includes providing a light source comprising a plurality of individually-controllable lighting elements for providing low angle dark field illumination; activating an image sensor for detecting image data reflected from an encoded data symbol when the encoded data symbol is illuminated by the light source; and providing a controller connected to each of the individually-controllable lighting elements, the controller being programmed for: selectively activating the individually-controllable lighting elements to vary the direction of the low angle dark field illumination provided by the light source; and processing the image data detected by the image.

Claims

1. A digital scanning device for decoding a digitally encoded symbol comprising:

a light source comprising individually-controllable lighting elements for providing low angle dark field illumination to an encoded data symbol;

an image sensor for detecting image data reflected from the encoded data symbol when illuminated by the light source; and

a controller connected to each of the individually-controllable lighting elements, the controller being programmed to selectively activate a subset of individually-controllable lighting elements, wherein when the subset of the individually-controllable lighting elements are activated the light source illuminates the data encoded symbol in a desired direction.

2. The digital scanning device of claim 1 wherein the controller is configured to selectively activate the lighting elements such that all of the individually-controllable lighting elements are activated.

3. The digital scanning device of claim 1 wherein the controller is configured to process the image data collected by the image sensor to decode the symbol.

4. The digital scanning device of claim 1, wherein the individually-controllable lighting elements comprise portions of at least one of a circular ring, an oval ring, or an elliptical ring.

5. The digital scanning device of claim 4, wherein the portions of the circular ring comprise quadrants.

6. The digital scanning device of claim 1, wherein the individually-controllable lighting elements comprise a plurality of electrically-connected individual light elements.

7. The digital scanning device of claim 1, wherein the individually-controllable lighting elements provide at least one of a rectangular ring, an oval ring or an elliptical ring.

8. The digital scanning device of claim 1, wherein the controller is programmed to evaluate the data acquired by the image sensor and to vary the light applied to the data symbol from the individually-controllable lighting elements to optimize symbol decoding.

9. The digital scanning device of claim 1, wherein the light source comprises a passive illumination pipe.

10. The digital scanning device of in claim 1, wherein the light source comprises an active light pipe.

11. The digital scanning device of claim 1 wherein the individually-controllable lighting elements comprise portions of a ring light source.

12. The digital scanning device of claim 11 wherein the portions of the ring light source comprise quadrants.

13. The digital scanning device of claim 1 further comprising a bright field light source for providing bright field illumination to the encoded data symbol.

14. A digital scanning device for decoding a digitally encoded symbol comprising:

a dark field light source comprising individually-controllable lighting elements for providing low angle dark field illumination to an encoded data symbol;

a bright field light source for providing bright field illumination to the encoded data symbol;

an image sensor for detecting image data reflected from the encoded data symbol when illuminated by the light source; and

a controller connected to each of the individually-controllable lighting elements and the bright filed light source, the controller being programmed to selectively activate a subset of the individually-controllable lighting elements and to selectively activate the bright field light source, wherein when a subset of the individually-controllable lighting elements are activated the light source illuminates the data encoded symbol in a desired direction.

15. A digital scanning device, comprising:

a ring light source comprising individually-controllable lighting elements providing low angle dark field illumination to an adjacent surface including a symbol to be decoded;

a controller connected to the ring light source for selectively activating a subset of the individually-controllable lighting elements, wherein when a subset of the individually-controllable lighting elements are activated the light source illuminates the data encoded symbol in a desired direction; and

an image sensor connected to the controller for acquiring image data of the symbol, wherein the controller is programmed to evaluate the image data to determine whether the image data is sufficient to decode the symbol and to vary the light projected from the light source until the image data is sufficient to decode the symbol.

16. The digital scanning device of claim 15, further comprising a bright field light source for providing bright field illumination to the adjacent surface, wherein the controller is further programmed to selectively activate the bright field light source to illuminate the symbol.

17. The digital scanning device of claim 15, wherein the ring light source comprises a passive light pipe.

18. The digital scanning device of claim 15, wherein the ring light source comprises an active light pipe.

19. The digital scanning device of claim 15, wherein the ring light source comprises a plurality of individually-controllable lighting segments.

20. The digital scanning device of claim 15, further comprising a memory component connected to the controller for storing light conditions.