Imaging module and reader for, and method of, expeditiously setting imaging parameters of imagers for imaging targets to be read over a range of working distances

Patent metadata

Field	Value
Publication number	US-10244180-B2
Application number	US-201615083493-A
Country	US
Kind code	B2
Filing date	Mar 29, 2016
Priority date	Mar 29, 2016
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

An imaging reader has near and far imagers for imaging illuminated targets to be read over a range of working distances. A range finder determines a distance to a target. A default imager captures a minor portion of an image of the target, and rapidly determines its light intensity level. At least one of the imagers is selected based on the determined distance and/or the determined light intensity level. The exposure and/or gain of the selected imager is set to a predetermined value, and an illumination level is determined, also based on the determined light intensity level and/or the determined distance. The selected imager, which has been set with the predetermined value, captures an image of the target, which has been illuminated at the illumination light level.

First claim

The invention claimed is:

1. An imaging module for setting at least one imaging parameter of at least one imager for imaging targets to be electro-optically read over a range of working distances away from the module, the module comprising:
an imaging assembly including a near imager for imaging targets over a relatively wider imaging field of view, and a far imager for imaging targets over a relatively narrower imaging field of view, the near imager being separate from the far imager;
an illuminating light assembly for illuminating targets with illumination light;
a range finder for determining a distance to a target; and
a main controller for controlling only a default one of the imagers to capture a minor portion of an image of the target, for determining a light intensity level of the captured minor portion of the image, for selecting at least one of the imagers based on at least one of the determined distance and the determined light intensity level, for controlling the illuminating light assembly to illuminate the target with illumination light at an illumination light level based on the at least one of the determined distance and the determined light intensity level, for setting the at least one imaging parameter of the selected at least one imager to a predetermined value based on the at least one of the determined light intensity level and the determined distance, and for controlling the selected at least one imager, which has been set with the predetermined value, to capture an image of the target, which has been illuminated at the illumination light level.

2. The module of claim 1 , and a memory accessible to the main controller for storing a plurality of predetermined values of the at least one imaging parameter for retrieval by the main controller, and wherein the predetermined values are different based on the at least one of the determined light intensity level and the determined distance.

3. The module of claim 2 , wherein the main controller includes an exposure controller and a gain controller, wherein the plurality of predetermined values stored in the memory include a set of exposure values for retrieval by the exposure controller and a set of gain values for retrieval by the gain controller, wherein the exposure values are different based on the at least one of the determined light intensity level and the determined distance, and wherein the gain values are different based on the at least one of the determined light intensity level and the determined distance.

4. The module of claim 1 , wherein the default imager is controlled by the main controller to operate at a predetermined frame rate, and wherein the main controller determines the light intensity level from the minor portion of the image at a rate faster than the predetermined frame rate.

5. The module of claim 1 , wherein the image is comprised of pixels arranged in a predetermined row number of rows and a predetermined column number of columns, and wherein the minor portion of the image is comprised of pixels arranged in a number of rows less than the predetermined row number and in a number of columns less than the predetermined column number.

6. The module of claim 1 , wherein the main controller is operative for controlling the illuminating light assembly to illuminate the target with illumination light having a relatively lesser illumination light level when the range finder determines that the target to be imaged and read is located in a close-in region of the range, for controlling the illuminating light assembly to illuminate the target with illumination light of a relatively greater illumination light level when the range finder determines that the target to be imaged and read is located in a far-out region of the range, and for controlling the illuminating light assembly to illuminate the target with illumination light of a relatively intermediate illumination light level that is between the lesser illumination light level and the greater illumination light level when the range finder determines that the target to be imaged and read is located in an intermediate region that is between the close-in region and the far-out region of the range.

7. The module of claim 1 , wherein the main controller varies the illumination light level as one of a continuous and a stepwise function based on the at least one of the determined distance and the determined light intensity level.

8. The module of claim 1 , wherein each imager captures return light from the target along an optical axis, and wherein the range finder includes an aiming assembly for emitting an aiming beam along an aiming axis that is offset from at least one of the optical axes.

9. An imaging reader for reading targets by image capture over a range of working distances away from the reader, comprising:
a housing having a light-transmissive window; and
an imaging module for setting at least one imaging parameter of at least one imager for imaging the targets, the module including
an imaging assembly including a near imager for imaging targets over a relatively wider imaging field of view, and a far imager for imaging targets over a relatively narrower imaging field of view, the near imager being separate from the far imager,
an illuminating light assembly for illuminating targets with illumination light,
a range finder for determining a distance to a target, and
a main controller for controlling only a default one of the imagers to capture a minor portion of an image of the target, for determining a light intensity level of the captured minor portion of the image, for selecting at least one of the imagers based on at least one of the determined distance and the determined light intensity level, for controlling the illuminating light assembly to illuminate the target with illumination light at an illumination light level based on the at least one of the determined distance and the determined light intensity level, for setting the at least one imaging parameter of the selected at least one imager to a predetermined value based on the at least one of the determined light intensity level and the determined distance, and for controlling the selected at least one imager, which has been set with the predetermined value, to capture an image of the target, which has been illuminated at the illumination light level.

10. The reader of claim 9 , and a memory accessible to the main controller for storing a plurality of predetermined values of the at least one imaging parameter for retrieval by the main controller, and wherein the predetermined values are different based on the at least one of the determined light intensity level and the determined distance.

11. The reader of claim 10 , wherein the main controller includes an exposure controller and a gain controller, wherein the plurality of predetermined values stored in the memory include a set of exposure values for retrieval by the exposure controller and a set of gain values for retrieval by the gain controller, wherein the exposure values are different based on the at least one of the determined light intensity level and the determined distance, and wherein the gain values are different based on the at least one of the determined light intensity level and the determined distance.

12. The reader of claim 9 , wherein the default imager is controlled by the main controller to operate at a predetermined frame rate, and wherein the main controller determines the light intensity level from the minor portion of the image at a rate faster than the predetermined frame rate.

13. The reader of claim 9 , wherein the image is comprised of pixels arranged in a predetermined row number of rows and

Assignees

• Symbol Technologies Llc

Inventors

• Tan Chinh
• Goren David P
• Kuchenbrod Harry E
• Wittenberg Carl D

Classifications

• H04N23/73 Primary

  by influencing the exposure time · CPC title

• H04N23/56

  provided with illuminating means · CPC title

• H04N23/74

  by influencing the scene brightness using illuminating means · CPC title

• H04N23/72 Primary

  Combination of two or more compensation controls · CPC title

• G06K7/10801 Primary

  Multidistance reading · CPC title