Imaging reader with adaptive illumination and adaptive resolution

• US 20090108074A1
• Filed: 10/31/2007
• Published: 04/30/2009
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Vinogradov, Igor
• Granted Patent: US 7,690,575 B2
• Time in Patent Office: Days
• US Class Current: 235/462.420
• CPC Class Codes: G06K 7/10732 Light sources
• CPC Class Codes: G06K 7/10772 Moved readers, e.g. pen, wand
• CPC Class Codes: G06K 7/10782 Slot readers
• CPC Class Codes: G06K 7/12 using a selected wavelength, e.g. to sense red marks and ignore blue marks

Abstract

Infrared light having a wavelength in a range from about 700 nm to about 760 nm, which is non-readily visible, illuminates indicia to be electro-optically read by default. Blue visible light having a wavelength in a range from about 430 nm to about 505 nm illuminates the indicia when high-density and/or low-contrast indicia are detected.

Claims

1. A reader for electro-optically reading indicia, comprising:

an illuminator for illuminating the indicia during reading, the illuminator including an energizable first light source for emitting non-readily visible illumination infrared light having a wavelength in a range from about 700 nm to about 760 nm when energized, and an energizable second light source for emitting visible illumination blue light having a wavelength in a range from about 430 nm to about 505 nm when energized;

a solid-state imager including an array of image sensors for capturing light scattered from the indicia illuminated by the illuminator over a field of view during reading, and for generating a signal corresponding the illuminated indicia; and

a controller for energizing at least one of the light sources to emit the illumination light to the illuminated indicia for capture by the imager, and for processing the signal to read the illuminated indicia.

6. The reader of claim 1, wherein the controller is operative for determining a contrast between elements of the illuminated indicia, and for energizing the second light source when the contrast determined by the controller is at least equal to a reference contrast value.

7. The reader of claim 6, wherein the controller is operative for energizing the first light source in a default mode, and for energizing the second light source only when the contrast determined by the controller is below the reference contrast value.

8. The reader of claim 7, wherein the controller is operative for continuously energizing the first light source in the default mode, and for energizing the second light source only for a time interval.

10. The reader of claim 1, and a housing for supporting the illuminator and the imager, and wherein the housing has a handle for handheld operation and a window through which the illumination light passes.

11. The reader of claim 1, and a housing for supporting the illuminator and the imager, and wherein the housing has a base for supporting the housing on a support surface for workstation operation and a window through which the illumination light passes.

2. (canceled)

3. (canceled)

9. (canceled)

12. (canceled)

13. A method of electro-optically reading indicia, comprising the steps of:

illuminating the indicia during reading, by emitting non-readily visible illumination infrared light having a wavelength in a range from about 700 nm to about 760 nm from an energizable first light source when energized, and by emitting visible illumination blue light having a wavelength in a range from about 430 nm to about 505 nm from an energizable second light source when energized;

capturing light scattered from the illuminated indicia over a field of view of a solid-state imager including an array of image sensors during reading, and generating a signal corresponding the illuminated indicia; and

energizing at least one of the light sources to emit the illumination light to the illuminated indicia for capture by the imager, and processing the signal to read the illuminated indicia.

18. The method of claim 13, and determining a contrast between elements of the illuminated indicia, and wherein the energizing step is performed by energizing the second light source when the determined contrast is at least equal to a reference contrast value.

19. The method of claim 18, wherein the energizing step is performed by energizing the first light source in a default mode, and by energizing the second light source only when the determined contrast is below the reference contrast value.

20. The method of claim 19, wherein the energizing step is performed by continuously energizing the first light source in the default mode, and by energizing the second light source only for a time interval.

22. The method of claim 13, and supporting the illuminator and the imager with a housing, and providing a handle on the housing for handheld operation, and providing a window on the housing for passing the illumination light.

23. The method of claim 13, and supporting the illuminator and the imager with a housing, and providing a base on the housing for supporting the housing on a support surface for workstation operation, and providing a window on the housing for passing the illumination light.

14. (canceled)

15. (canceled)

21. (canceled)

24. A reader for electro-optically reading indicia, comprising:

an illuminator for illuminating the indicia during reading, the illuminator including an energizable first light source for emitting non-readily visible illumination light when energized, and an energizable second light source for emitting visible illumination light when energized;

a solid-state imager including an array of image sensors for capturing light scattered from the indicia illuminated by the illuminator over a field of view during reading, and for generating a signal corresponding the illuminated indicia; and

a controller for determining a density of the illuminated indicia, and for energizing the second light source when the density determined by the controller is at least equal to a reference density value to emit the illumination light to the illuminated indicia for capture by the imager, and for processing the signal to read the illuminated indicia.

4. The reader of claim 24, wherein the controller is operative for energizing the first light source in a default mode, and for energizing the second light source only when the density determined by the controller equals or exceeds the reference density value.

5. The reader of claim 4, wherein the controller is operative for continuously energizing the first light source in the default mode, and for energizing the second light source only for a time interval.

25. A reader for electro-optically reading indicia, comprising:

an illuminator for illuminating the indicia during reading, the illuminator including an energizable first light source for emitting non-readily visible illumination light when energized, and an energizable second light source for emitting visible illumination light when energized;

a solid-state imager having a resolution and including an array of image sensors for capturing light scattered from the indicia illuminated by the illuminator over a field of view during reading, and an imaging lens for focusing the light from the illuminated indicia onto the array of image sensors, the imager being operative for generating a signal corresponding to the illuminated indicia; and

a controller for energizing the second light source to increase the resolution of the imager and to emit the illumination light to the illuminated indicia for capture by the imager, and for processing the signal to read the illuminated indicia.

26. A method of electro-optically reading indicia, comprising the steps of:

illuminating the indicia during reading, by emitting non-readily visible illumination light from an energizable first light source when energized, and by emitting visible illumination light from an energizable second light source when energized;

capturing light scattered from the illuminated indicia over a field of view of a solid-state imager including an array of image sensors during reading, and generating a signal corresponding the illuminated indicia; and

determining a density of the illuminated indicia, and energizing the second light source when the determined density is at least equal to a reference density value to emit the illumination light to the illuminated indicia for capture by the imager, and processing the signal to read the illuminated indicia.

16. The method of claim 26, wherein the energizing step is performed by energizing the first light source in a default mode, and by energizing the second light source only when the determined density equals or exceeds the reference density value.

17. The method of claim 16, wherein the energizing step is performed by continuously energizing the first light source in the default mode, and by energizing the second light source only for a time interval.

27. A method of electro-optically reading indicia, comprising the steps of:

illuminating the indicia during reading, by emitting non-readily visible illumination light from an energizable first light source when energized, and by emitting visible illumination light from an energizable second light source when energized;

capturing light scattered from the illuminated indicia over a field of view of a solid-state imager including an array of image sensors during reading, focusing the light from the illuminated indicia onto the array of image sensors, and generating a signal corresponding the illuminated indicia; and

energizing the second light source to increase a resolution of the imager to emit the illumination light to the illuminated indicia for capture by the imager, and processing the signal to read the illuminated indicia.