Systems and methods for illuminating a scan volume of an optical code reader

• US 8,632,011 B2
• Filed: 01/17/2012
• Issued: 01/21/2014
• Est. Priority Date: 01/18/2011
• Status: Active Grant

• Current Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Original Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Inventors: Gao, WenLiang
• Primary Examiner(s): Frech, Karl D
• Application Number:
  US13/352,257
• Publication Number:
  US 20120181338A1
• Time in Patent Office: 735 Days
• Field of Search: 235/445, 235/462.2, 235/462.21, 235/462.22, 235/455
• US Class Current: 235/455
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10801 Multidistance reading
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks
• CPC Class Codes: G06K 7/1439 including a method step for retrieval of the optical code
• CPC Class Codes: G06K 7/1443 locating of the code in an image

Abstract

Methods and systems of illuminating a scan volume of an optical code reader are disclosed. In an example configuration, an illumination source associated with the optical code reader is set to a first illumination mode based on a user-configurable parameter that at least partially defines a first depth of field of the optical code reader when the illumination source illuminates the scan volume; while the illumination source is in the first illumination mode, the scan volume is monitored for an indication of whether an object is detected in the scan volume; and if an object is detected in the scan volume while the illumination source is in the first illumination mode, the illumination source is set to a second illumination mode.

Claims

1. A method of illuminating a scan volume of an optical code reader, comprising the steps of:

illuminating the scan volume of the optical code reader with an illumination source set at a first illumination mode, the first illumination mode having associated therewith a user-configurable parameter that at least partially defines a first depth of field of the optical code reader when the illumination source illuminates the scan volume;

while the illumination source is in the first illumination mode, monitoring the scan volume for an indication of whether an object is detected in the scan volume; and

if an object is detected in the scan volume while the illumination source is in the first illumination mode, illuminating the scan volume of the optical code reader with the illumination source set at a second illumination mode.

2. The method of claim 1, wherein monitoring the scan volume for an indication of whether an object is detected in the scan volume comprises processing image data associated with the scan volume for decodable data corresponding to an optical code.

3. The method of claim 1, further comprising:

while the illumination source is in the second illumination mode, monitoring the scan volume for an indication of whether no object is detected in the scan volume; and

if no object is detected in the scan volume while the illumination source is in the second illumination mode, automatically setting the illumination source associated with the optical code reader to the first illumination mode.

4. The method of claim 1, further comprising:

while the illumination source is in the second illumination mode, monitoring the scan volume for an indication of whether no object is detected in the scan volume for a predetermined period of time; and

if no object is detected in the scan volume for a predetermined period of time while the illumination source is in the second illumination mode, automatically setting the illumination source associated with the optical code reader to the first illumination mode.

5. The method of claim 1, further comprising:

in response to a user request to increase the first depth of field of the optical code reader when the illumination source is in the first illumination mode, updating the user-configurable parameter so that the first depth of field is increased from a first distance to a second distance that is greater than the first distance.

6. The method of claim 1, wherein the second illumination mode has associated therewith a user-configurable parameter that at least partially defines a second depth of field of the optical code reader when the illumination source illuminates the scan volume.

7. The method of claim 6, wherein the second depth of field is greater than the first depth of field.

8. The method of claim 1, wherein the optical code reader is a data acquisition device selected from the group consisting of an imaging reader and a laser scanner.

9. An optical code reader, comprising:

an illumination source configured to illuminate a scan volume of the optical code reader;

an imager configured to acquire an image of an optical code within the scan volume of the optical code reader; and

a controller in operative association with the illumination source and the imager, the controller configured to;

cause the illumination source to operate in a first illumination mode, the first illumination mode having associated therewith a user-configurable parameter that at least partially defines a first depth of field of the optical code reader when the illumination source illuminates the scan volume;

while the illumination source operates in the first illumination mode, cause the imager to acquire a first set of images of the scan volume, wherein the first set of images includes one or more images of the scan volume;

determine, based on the first set of images, whether an object is within the scan volume of the optical code reader; and

if it is determined, based on the first set of images, that an object is within the scan volume of the optical code reader, cause the illumination source to operate in a second illumination mode.

10. The optical code reader of claim 9, wherein the controller further configured to:

while the illumination source operates in the second illumination mode, cause the imager to acquire a second set of images of the scan volume, wherein the second set of images includes one or more images of the scan volume;

determine, based on the second set of images, whether an object is within the scan volume of the optical code reader; and

if it is determined, based on the second set of images, that no object is within the scan volume of the optical code reader, cause the illumination source to operate in the first illumination mode.

11. The optical code reader of claim 10, wherein the controller is configured to cause the illumination source to operate in the first illumination mode if it is determined that no object is within the scan volume of the optical code reader in a predetermined number of images in the second set of images.

12. The optical code reader of claim 10, wherein the controller is configured to cause the illumination source to operate in the first illumination mode if it is determined, based on the second set of images, that no object is within the scan volume of the optical code reader for a predetermined period of time.

13. The optical code reader of claim 10, wherein each image in the second set of images includes light intensity values corresponding to the intensity of light incident on sensor pixels of the imager and the controller is configured to:

calculate a percentage of the light intensity values in an image in the second set of images that are less than or equal to a light intensity threshold value,

compare the calculated percentage to a predetermined percentage to determine whether the calculated percentage is greater than or equal to the predetermined percentage, and

if it is determined that the calculated percentage is greater than or equal to the predetermined percentage, cause the illumination source to operate in the first illumination mode.

14. The optical code reader of claim 9, wherein the second illumination mode increases a depth of field of the optical code reader from the first depth of field to a second depth of field.

15. The optical code reader of claim 9, wherein:

the illumination source is configured to illuminate the scan volume with a series of illumination pulses having a pulse width,

the user-configurable parameter associated with the first illumination mode comprises the pulse width of the illumination pulses, and

the controller is configured to cause the pulse width of the illumination pulses to increase from a first pulse width to a second pulse width while the illumination source operates in the second illumination mode.

16. The optical code reader of claim 9, wherein:

the illumination source comprises at least one light-emitting diode,

the user-configurable parameter associated with the first illumination mode comprises a drive current of said at least one light-emitting diode, and

the controller is configured to cause the drive current of said at least one light-emitting diode to increase from a first drive current to a second drive current while the illumination source operates in the second illumination mode.

17. The optical code reader of claim 9, wherein:

the illumination source comprises at least one light-emitting diode that is configured to illuminate the scan volume with a series of illumination pulses having a pulse width,

the user-configurable parameter associated with the first illumination mode comprises the pulse width of the illumination pulses and a drive current of said at least one light-emitting diode,

the controller is configured to cause the drive current of said at least one light-emitting diode to increase from a first drive current to a second drive current while the illumination source operates in the second illumination mode, and

the controller is configured to cause the pulse width of the illumination pulses to increase from a first pulse width to a second pulse width while the illumination source operates in the second illumination mode.

18. The optical code reader of claim 9, wherein:

the illumination source comprises a first light-emitting diode that is configured to illuminate the scan volume with light having a wavelength within a wavelength band of approximately 380 nm to approximately 750 nm and a second light-emitting diode that is configured to illuminate the scan volume with light having a wavelength within a wavelength band of approximately 750 nm to approximately 300 μ

m,

the controller is configured to cause only the first light-emitting diode to illuminate the scan volume while the illumination source operates in the first illumination mode, and

the controller is configured to cause both the first and second light-emitting diodes to illuminate the scan volume while the illumination source operates in the second illumination mode.

19. The optical code reader of claim 9, wherein:

the controller is configured to determine, based on the first set of images, whether an object including an optical code is within the scan volume of the optical code reader by processing the first set of images for decodable data corresponding to an optical code, and

the controller is configured to cause the illumination source to operate in the second illumination mode if it is determined, based on the first set of images, that an object including an optical code is within the scan volume of the optical code reader.

20. The optical code reader of claim 9, wherein each image in the first set of images includes light intensity values corresponding to the intensity of light incident on sensor pixels of the imager and the controller is configured to:

calculate a percentage of the light intensity values in an image in the first set of images that are greater than or equal to a light intensity threshold value,

compare the calculated percentage to a predetermined percentage to determine whether the calculated percentage is greater than or equal to the predetermined percentage, and

if it is determined that the calculated percentage is greater than or equal to the predetermined percentage, cause the illumination source to operate in the second illumination mode.