Hand held bar code reader with improved image capture

• US 20070272756A1
• Filed: 05/26/2006
• Published: 11/29/2007
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Brock, Christopher, Lackemann, Thomas, Pang, Robert
• Granted Patent: US 7,475,823 B2
• Time in Patent Office: Days
• US Class Current: 235/462.250
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/109 adaptations to make the hand-held scanner useable as a fixed scanner

Abstract

An imaging-based bar code reader that includes an imaging and decoding system. When used on a stand to image documents, typically neither the stand or document is moving. Therefore blurring due to motion is not an issue. A sensor detects when the scanner is mounted to a stand. When commanded to take an image the scanner electronics and software modifies an auto-exposure process to minimize gain and lengthen exposure. This modification results in the scanner that is effective for scanning bar codes and yet also takes excellent pictures when mounted to a stand.

Claims

1. An imaging-based reader for reading a target comprising:

a) an imaging and decoding system for imaging a target image and if present decoding a target bar code, the imaging and decoding system including focusing optics and a sensor array, the focusing optics defining a field of view and focusing reflected illumination from an image onto the sensor array; and

b) a monitor for determining if the reader is stationary with respect to the target, and wherein said imaging and decoding system responds to the monitor by adjusting an exposure period in situations wherein the reader is stationary with respect to the target.

2. The reader of claim 1 wherein the exposure period is lengthened and signal values accessed from the sensor array amplified with less gain if the imaging and decoding system is stationary with respect to the target image.

3. The reader of claim 1 wherein a ceiling on gain adjustment is determined based on a noise sensitivity of the imaging and decoding system.

4. The reader of claim 1 additionally comprising a controller having software for causing the imaging and decoding system to lengthen exposure times regardless of an output of the monitor.

5. The reader of claim 1 additionally comprising a controller having software that lengthens the exposure time of a subsequent image based on multiple images of a target to determine relative motion between the target and the reader.

6. The reader of claim 4 wherein the controller responds to a command from a serial interface used to communicate commands with the reader.

7. The reader of claim 4 wherein the controller responds to a scanned bar code to adjust exposure times.

8. (canceled)

9. A method of reading a target comprising:

a) providing an imaging and decoding system for imaging a target image and possibly decoding a target bar code, the imaging and decoding system including focusing optics and a sensor array, the focusing optics defining a field of view and focusing reflected illumination from the target bar code onto the sensor array;

b) determining if the imaging and decoding system is deemed to be stationary with respect to the target image; and

c) if the imaging and decoding system is deemed to be stationary, capturing an image with an exposure time period long enough to reduce distortion caused by processing electronics of the imaging and decoding system.

10. Process of claim 9 wherein the exposure time is approximately one half second.

11. The process of claim 9 wherein the determining is performed by sensing if a housing supporting the imaging and decoding system is mounted to a support stand during image capture.

12. The process of claim 9 wherein the exposure period is lengthened and signal values accessed from the sensor array amplified with less gain if the imaging and decoding system is deemed to be stationary with respect to the target image.

13. For use with an image reader that reads images such as bar codes, apparatus comprising

a controller executing software for adjusting exposure capture times and signal gain from an imaging circuit during capture of images;

and

a monitor for determining an exposure mode and communicating said exposure mode to the controller in situations where blurring of images is not of concern due to a fixed relation between the image reader and the image.

15. The apparatus of claim 13 wherein the monitor comprises a communications interface for communicating commands to said controller from an outside source.

14. (canceled)

16. Apparatus for reading a target comprising:

a) imaging and decoding means for imaging the target and possibly decoding a target bar code, said means including focusing optics and a sensor array and processing electronics for processing signals from the sensor array, the focusing optics defining a field of view and focusing reflected illumination from the target bar code onto the sensor array;

b) means for determining if the focusing optics and sensor array is stationary with respect to the target image; and

c) said means for determining interacting with the imaging and decoding means such that if the focusing optics and sensor array is determined to be stationary, said means for imaging captures an image with an exposure time period long enough to reduce distortion caused by processing electronics of the imaging and decoding means.

18. The apparatus of claim 16 wherein the means for determining senses if a housing supporting the imaging and decoding means is mounted to a support stand during image capture.

19. The apparatus of claim 16 wherein the exposure period is lengthened and signal values accessed from the sensor array amplified with less gain if the imaging and decoding means is deemed to be stationary with respect to the target image.

17. The apparatus of 16 wherein the imaging and decoding means increases an exposure time up to one half second.

20. A computer readable medium containing computer executable instructions to perform a method for processing a target image with a reader, the method comprising:

a) determining if an imaging and decoding system of the reader is deemed to be stationary with respect to the target image; and

b) if the imaging and decoding system is deemed to be stationary, capturing an image with an exposure time period long enough to reduce distortion caused by processing electronics of the imaging and decoding system.

21. The method of claim 20 wherein the determining is performed by sensing if a housing supporting the imaging and decoding system is mounted to a support stand during image capture.

22. The method of claim 20 wherein the exposure period is lengthened and signal values accessed from the sensor array amplified with less gain if the imaging and decoding system is deemed to be stationary with respect to the target image.

23. An imaging-based reader for reading a target comprising:

a) an imaging and decoding system for imaging a target image and if present decoding a target bar code, the imaging and decoding system including focusing optics and a sensor array, the focusing optics defining a field of view and focusing reflected illumination from an image onto the sensor array; and

b) a monitor for determining if the reader is stationary with respect to the target, and wherein said imaging and decoding system responds to the monitor by adjusting an exposure period in situations wherein the reader is stationary with respect to the target, wherein the monitor is a combination of a reed switch and a magnet.

24. For use with an image reader that reads images such as bar codes, apparatus comprising:

a controller executing software for adjusting exposure capture times and signal gain from an imaging circuit during capture of images; and

a monitor for determining an exposure mode and communicating said exposure mode to the controller in situations where blurring of images is not of concern due to a fixed relation between the image reader and the image wherein the controller is fixed within a housing and the monitor comprises a switch for sensing a presence of a magnet in either a stand for the housing or a housing body.