Terminal with flicker-corrected aimer and alternating illumination

Patent metadata

Field	Value
Publication number	US-9659199-B2
Application number	US-201615176366-A
Country	US
Kind code	B2
Filing date	Jun 8, 2016
Priority date	Jan 31, 2011
Publication date	May 23, 2017
Grant date	May 23, 2017

Abstract

An indicia reading terminal is disclosed that eliminates unwanted flickering effects in an illuminated screen reading mode, among other advantageous features. The indicia reading terminal, in response to a screen reading signal, is operative to activate a screen reading cycle. In the screen reading cycle, an imaging subsystem is activated at least once at the same time that an illumination subsystem is activated for one of a plurality of active illumination periods, for a first illuminated exposure period. The imaging subsystem is activated at least once while the illumination subsystem is not activated, for a first unilluminated exposure period, which is longer than the first illuminated exposure period. An aimer subsystem is activated for a plurality of active aimer periods when neither the imaging subsystem nor the illumination subsystem is activated, wherein intervals of time between the active aimer periods are equal, within nominal tolerances.

First claim

What is claimed is:

1. An indicia reading terminal comprising:
an illumination subsystem operative for projecting an illumination pattern;
an aimer subsystem operative for projecting an aiming pattern;
an imaging subsystem comprising an image sensor array and an imaging optics assembly operative for focusing an image onto the image sensor array;
a processor operative to attempt to decode a decodable indicia represented in at least one of the frames of image data;
wherein the indicia reading terminal, in response to a reading signal, is operative to activate a reading cycle, wherein:
the imaging subsystem is activated to acquire frames of image data at least once at the same time that the illumination subsystem is activated for one of a plurality of active illumination periods, for a first illuminated exposure period, wherein intervals of time between the active illumination periods are equal, within nominal tolerances; and
the imaging subsystem is activated to acquire frames of image data at least once while the indicia reading terminal does not project illumination, for a first unilluminated exposure period, which is longer than the first illuminated exposure period.

2. The terminal of claim 1 , wherein the terminal is operative such that the active illumination periods last an equal amount of time, within nominal tolerances.

3. The terminal of claim 1 , wherein the terminal is operative such that intervals of time from a beginning of one of the active illumination periods to the beginning of an immediately subsequent active illumination period are less than or equal to 40 milliseconds.

4. The terminal of claim 1 , wherein the terminal is operative such that the imaging subsystem captures a first illuminated frame of image data during the first illuminated exposure period, the imaging subsystem captures a first unilluminated frame of image data during the first unilluminated exposure period, and the processor attempts to decode a decodable indicia from both the illuminated frame of image data and the unilluminated frame of image data.

5. The terminal of claim 1 , wherein the terminal is operative such that the first illuminated exposure period is activated prior to the first unilluminated exposure period.

6. The terminal of claim 1 , wherein the terminal is operative such that the aimer subsystem is activated for a first active aimer period that is after the first illuminated exposure period and before the first unilluminated exposure period, and the aimer subsystem is activated for a second active aimer period that is after the first unilluminated exposure period and before a second illuminated exposure period.

7. The terminal of claim 6 , wherein the terminal is operative such that the active aimer periods are equal, within nominal tolerances; the intervals of time between the active aimer periods are equal, within nominal tolerances; the active illumination periods are equal, within nominal tolerances; and the intervals of time between the active illumination periods are equal, within nominal tolerances, from one reading cycle to the next as the reading cycle is activated a plurality of times in sequence.

8. A terminal, comprising:
an illumination subsystem operative for projecting an illumination pattern;
an aimer subsystem operative for projecting an aiming pattern;
an imaging subsystem comprising an image sensor array and an imaging optics assembly operative for focusing an image onto the image sensor array;
a processor operative to attempt to decode a decodable indicia represented in at least one of the frames of image data;
wherein the terminal, in response to a reading signal, is operative to activate a reading cycle, wherein:
the illumination subsystem is activated to project an illumination pattern and at the same time the imaging subsystem is activated to acquire frames of image data for an illuminated exposure period;
while the imaging subsystem and illumination subsystem are inactive, the aimer subsystem is activated to project an aiming pattern for a first active aimer period;
while the illumination subsystem and aimer subsystem are inactive, the imaging subsystem is activated, for an unilluminated exposure period, to acquire frames of image data;
while the imaging subsystem is inactive, the illumination subsystem is activated to project an illumination pattern for a non-exposure illumination period;
while the imaging subsystem and illumination subsystem are inactive, the aimer subsystem is activated to project an aiming pattern for a second active aimer period.

9. The terminal of claim 8 , wherein the reading cycle lasts approximately 34 milliseconds.

10. The terminal of claim 8 , wherein the terminal is operative such that the intervals of time from a beginning of one of the active aimer periods to the beginning of an immediately subsequent, corresponding active aimer period are less than or equal to 40 milliseconds.

11. The terminal of claim 8 , wherein the terminal is operative such that the illuminated exposure period lasts for less than or equal to two milliseconds.

12. The terminal of claim 8 , wherein the terminal is operative such the first active aimer period lasts for between two and eight milliseconds.

13. The terminal of claim 8 , wherein the terminal is operative to activate the reading cycle on an open loop basis while the reading signal is active.

14. A terminal, comprising:
an illumination subsystem operative for projecting an illumination pattern;
an aimer subsystem operative for projecting an aiming pattern;
an imaging subsystem comprising an image sensor array and an imaging optics assembly operative for focusing an image onto the image sensor array;
wherein the terminal, in response to a reading signal, is operative to activate a reading cycle, wherein:
the illumination subsystem is activated to project an illumination pattern and at the same time the imaging subsystem is activated to acquire frames of image data for an illuminated exposure period;
while the imaging subsystem and illumination subsystem are inactive, the aimer subsystem is activated to project an aiming pattern for a first active aimer period;
while the illumination subsystem and aimer subsystem are inactive, the imaging subsystem is activated to acquire frames of image data for an unilluminated exposure period;
while the imaging subsystem is inactive, the illumination subsystem is activated to project an illumination pattern for a non-exposure illumination period, wherein the non-exposure illumination period has the same duration as the illuminated exposure period; and
while the imaging subsystem and illumination subsystem are inactive, the aimer subsystem is activated to project an aiming pattern for a second active aimer period, wherein the second active aimer period has the same duration as the first active aimer period.

15. The terminal of claim 14 , wherein intervals of time between the first active aimer period and the second active aimer period, within and between screen reading cycles, are equal, within nominal tolerances.

16. The terminal of claim 14 , wherein intervals of time between the illuminated exposure period and the non-exposure illumination period, within and between screen reading cycles, are equal, within nominal tolerances.

17. The terminal of claim 14 , wherein:
intervals of time between the first active aimer period and the second active aimer period, within and between screen reading cycles, are equal, within nominal tolerances; and
intervals of time between the illuminated exposure period and the non-exposure illuminat

Assignees

• Hand Held Prod Inc

Inventors

• Van Volkinburg Daniel
• Deloge Stephen Patrick
• Bower Kevin
• Pankow Matthew
• Kather Ryan

Classifications

• G06K7/10752

  Exposure time control · CPC title

• G06K2019/06225

  using wavelength selection, e.g. colour code · CPC title

• G06K7/10811

  Focalisation · CPC title

• G06K2207/1011

  Aiming · CPC title

• G06K7/10732 Primary

  Light sources · CPC title