Mark reader with reduced trigger-to-decode response time

• US 9,298,963 B2
• Filed: 12/23/2010
• Issued: 03/29/2016
• Est. Priority Date: 12/23/2010
• Status: Active Grant

• Current Assignee: Cognex Corporation
• Original Assignee: Cognex Corporation
• Inventors: Negro, James A.
• Primary Examiner(s): Le, Thien M
• Assistant Examiner(s): TAYLOR, APRIL ALICIA
• Application Number:
  US12/978,156
• Publication Number:
  US 20120160918A1
• Time in Patent Office: 1,923 Days
• Field of Search: 235/454, 235/455, 23546201-46245, 235/462.48, 235/470, 235/472.01, 382/255
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10881 constructional details of hand-held scanners
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1439 including a method step for retrieval of the optical code

Abstract

Systems and methods for use with a handheld mark reader that reduce the time between activation of the reader'"'"'s trigger and the reader returning a successful decode response. Image processing may be performed prior to the user actuating the trigger and thus obtaining a decodable image with reduced delay. Separate pre-trigger and post-trigger parameters may be used for image decoding. A feedback loop may be incorporated for repeated parameter updates. An adjustable lens may be utilized either with illumination OFF or ON.

Claims

1. A handheld mark reader comprising:

the reader having a manual trigger;

an image acquisition sensor that acquires at least one pre-trigger image of the mark prior to an actuation of the manual trigger and acquires at least one post-trigger image of the mark after the actuation of the manual trigger;

a pre-trigger calculation process that calculates, for the at least one pre-trigger image, at least one pre-trigger image parameter including at least one of a gain and a focal setting;

a decode process that decodes the at least one post-trigger image; and

a feedback process that uses the at least one pre-trigger image parameter to control at least one of a post-trigger image acquisition process and the decode process.

2. The handheld mark reader according to claim 1 wherein the feedback process comprises a pre-trigger feedback loop that determines the at least one pre-trigger image parameter prior to the actuation of the trigger.

3. The handheld mark reader according to claim 2 wherein the pre-trigger feedback loop comprises an image acquisition process, an image analysis process, and a configure pre-trigger parameters process.

4. The handheld mark reader according to claim 1 further including a post-trigger image acquisition process that uses the at least one pre-trigger image parameter to acquire the at least one post-trigger image.

5. The handheld mark reader according to claim 1 wherein the at least one pre-trigger image parameter further includes exposure.

6. The handheld mark reader according to claim 1 wherein the focal setting pre-trigger image parameter comprises an auto-focus parameter.

7. The handheld mark reader according to claim 1 wherein the focal setting pre-trigger image parameter comprises a focal setting for a liquid lens.

8. A handheld mark reader for reading a mark comprising:

a reader body supporting a manual trigger and an image acquisition sensor, the sensor configured to acquire a pre-trigger image of the mark and a post-trigger image of the mark;

a pre-trigger image acquisition process;

a first pre-trigger calculation process that calculates, for the pre-trigger image, at least one parameter of exposure and gain;

a first decode process that attempts to decode the pre-trigger image prior to operation of the manual trigger;

a post-trigger image acquisition process;

a second decode process that attempts to decode the post-trigger image; and

a feedback process that uses the first calculated at least one parameter to control at least one of the post-trigger image acquisition process and the second decode process.

9. The handheld mark reader according to claim 8 wherein an illumination source is OFF during the pre-trigger image acquisition process.

10. The handheld mark reader according to claim 8 wherein an illumination source is OFF during the pre-trigger image acquisition process and ON during the post-trigger image acquisition process.

11. The handheld mark reader according to claim 8 wherein an illumination source is turned ON prior to the pre-trigger image acquisition process.

12. The handheld mark reader according to claim 8 further including a second pre-trigger calculation process that calculates, for the pre-trigger image, at least one of contrast and sharpness.

13. The handheld mark reader according to claim 8 wherein the first pre-trigger calculation process comprises a feedback loop including an image acquisition process, an image analysis process, and a configure pre-trigger parameters process.

14. The handheld mark reader according to claim 13 wherein information from at least one of the image analysis process and the first decode process is used to optimize the post-trigger image acquisition process.

15. The handheld mark reader according to claim 13 wherein information from the first image decode process is used in a determination of a confidence level of the second decode process.

16. A mark reader for decoding an image, the reader comprising:

a body;

an imager sensor within the body, the image sensor configured to acquire a pre-trigger image of at least a portion of a mark;

the body having a manually operable trigger, the trigger configured to activate the image sensor to acquire a post-trigger image of the at least a portion of the mark;

a processor operatively coupled to the trigger and the image sensor, the processor configured to activate the image sensor prior to operation of the trigger to acquire the pre-trigger image of the at least a portion of the mark and to calculate, for the pre-trigger image acquired prior to operation of the trigger, at least one of auto-exposure, auto-gain, auto-focus, and image decode; and

the processor further configured to decode the post-trigger image acquired after activation of the trigger using at least one of the calculated auto-exposure, auto-gain, auto-focus, and image decode.

17. The mark reader according to claim 16 further including a pre-trigger feedback loop for determining pre-trigger image parameters based on a non-illuminated pre-trigger image, and a post-trigger feedback loop for calculating post-trigger image parameters based on an illuminated post-trigger image.

18. The mark reader according to claim 16 wherein the pre-trigger image parameters are used for a first post-trigger image acquisition, and the post-trigger image parameters are used for subsequent post-trigger image acquisitions.

19. A method for decoding an image of a mark using a handheld mark reader, the reader including a trigger configured to initiate an acquisition of the image of the mark, the method comprising:

a) providing a processor, the processor operatively coupled to the trigger and to an image acquisition sensor;

b) activating the processor to acquire a pre-trigger image of the mark prior to actuation of the trigger;

c) analyzing the pre-trigger image, and based on the analyzing;

d) calculating a pre-trigger acquisition parameter including one or more of a gain and a focal setting;

e) adjusting the image acquisition sensor using the calculated pre-trigger acquisition parameter;

f) repeating steps b) through e) until the trigger is actuated;

g) after the trigger is actuated, acquiring a post-trigger image of the mark using the calculated pre-trigger acquisition parameter; and

h) decoding the post-trigger image.

20. The method according to claim 19 further including turning an illumination source ON after the trigger is actuated.

21. The method according to claim 19 further including, before the trigger is actuated, determining if the pre-trigger image meets predetermined image threshold values.

22. The method according to claim 19 further including, before the trigger is actuated, attempting to decode the pre-trigger image.

23. The method according to claim 19 wherein the pre-trigger acquisition parameter includes a focal setting for an adjustable lens.

24. The method according to claim 19 wherein the pre-trigger acquisition parameter includes a focal setting for a liquid lens.

25. The method according to claim 19 wherein the pre-trigger parameter comprises an auto-focus parameter.