ADAPTIVE DATA READER AND METHOD OF OPERATING

• US 20120000982A1
• Filed: 05/12/2011
• Published: 01/05/2012
• Est. Priority Date: 06/30/2010
• Status: Active Grant

• Current Assignee: Datalogic Adc, Inc. (Datalogic S.p.A.)
• Original Assignee: Datalogic Scanning Incorporated (Datalogic S.p.A.)
• Inventors: GAO, WenLiang, CHERRY, Craig D.
• Granted Patent: US 8,573,497 B2
• Time in Patent Office: Days
• US Class Current: 235/455
• CPC Class Codes: G06K 7/146 the method including quality enhancement steps

Abstract

Disclosed systems and methods preferably capture one or more images of an item bearing an optical code and analyze such images to determine whether the item has a highly, or relatively highly, reflective surface or not. Based on such a determination, operating parameters of the system, such as the gain, exposure time, and amount of illumination, are preferably automatically adjusted by the system to capture a subsequent image of the item where the subsequent image has sufficient contrast to decode the optical code. The subsequent image may include a plurality of images, and different operating parameters may be used to capture several, or each, of the plurality of images based on the determination of whether the item has a highly, or relatively highly, reflective surface or not.

Claims

1. A method for data reading comprising the steps of:

capturing, via a data reader, a first set of images of an item bearing an optical code;

performing an analysis of the first set of images to determine whether the item is in a recognized item class;

automatically setting adjusted operating parameters of the data reader based on the analysis of the first set of images of whether the item is in the recognized item class;

capturing, via the data reader, a second set of images of the item bearing the optical code using the adjusted operating parameters; and

processing the second set of images to decode the optical code appearing in the second set of images of the item.

2. A method according to claim 1 wherein processing the second set of images further includes:

performing an analysis of the second set of images to determine whether the item is in a recognized item class; and

automatically adjusting operating parameters of the data reader based on the analysis of the second set of images of whether the item is in the recognized item class.

3. A method according to claim 1 wherein the recognized item class consists essentially of objects bearing an optical code (a) on a display screen, (b) on or under a glass surface, (c) on a metal surface having a reflectance of at least about 30%, and (d) on a plastic surface having a reflectance of at least about 30%.

4. A method according to claim 1 wherein the step of performing an analysis of the first set of images includes recognizing a first shape nested within a similar second shape to identify an item bearing an optical code on a display screen.

5. A method according to claim 4 further comprising the steps of:

determining an average brightness of the first shape by the data reader;

determining an average brightness of an area surrounding the first shape by the data reader; and

comparing the average brightness of the first shape against the average brightness of the area surrounding the first shape to determine whether the display screen is backlit;

wherein the step of setting adjusted operating parameters is further based on whether the display screen is backlit.

6. A method according to claim 1 further comprising:

providing the data reader with an initial operating parameter set that includes (i) a baseline gain and exposure duration for an imager and (ii) an illumination setting for an illumination source;

wherein the step of automatically setting adjusted operating parameters includes;

(a) if the item is in the recognized item class, establishing a secondary operating parameter set for capturing a second set of images wherein the secondary operating parameter set includes (i) an increased one or both of a gain and an exposure duration for the imager when compared to the initial operating parameter set and (ii) a decreased illumination setting for the illumination source when compared to the initial operating parameter set; and

(b) if the item is not in the recognized item class, establishing the initial operating parameter set for capturing a second set of images.

7. A method according to claim 6 wherein the step of automatically adjusting operating parameters further includes:

(c) establishing the secondary operating parameter set for capturing a majority of the images and establishing the initial operating parameter set for capturing a minority of the images if the item is in the recognized item class; and

(d) establishing the initial operating parameter set for capturing a majority of the images and establishing the secondary operating parameter set for capturing a minority of the images if the item is not in the recognized item class.

8. A method according to claim 7 wherein:

the secondary operating parameter set is established for capturing about 75% of the images and the initial operating parameter set is established for capturing about 25% of the images if the item is in the recognized item class; and

the initial operating parameter set is established for capturing about 75% of the images and the secondary operating parameter set is established for capturing about 25% of the images if the item is not in the recognized item class.

9. A method according to claim 1 wherein the step of decoding the optical code includes automatically adjusting the data reader to first attempt to decode a particular type of optical code based on whether the item is in the recognized item class.

10. A method according to claim 1 wherein:

the step of performing analysis of the first set of images further includes identifying the item; and

the step of decoding the optical code further includes automatically adjusting the data reader to attempt to decode a particular type of optical code first based on identifying the item.

11. A system for data reading comprising:

an imager for capturing an image of an item bearing an optical code;

an illumination source for illuminating the item; and

a controller for operating the imager and the illumination source, wherein the controller is programmed to,

operate the imager to capture a first set of images of the item bearing an optical code;

analyze the first set of images to determine whether the item is in a recognized item class;

automatically adjust operating parameters of the imager and the illumination source based on whether the item is in the recognized item class;

operate the imager to capture a second set of images of the item using the adjusted operating parameters; and

analyze the optical code appearing in the second set of images of the item.

12. A system for data reading according to claim 11, wherein during analyzing the optical code the controller is further programmed to:

analyze the second set of images to determine whether the item is in a recognized item class; and

automatically adjust operating parameters of the imager and the illumination source based on whether the item is in the recognized item class.

13. A system for data reading according to claim 11, wherein the controller is further programmed to:

recognize a combination of a first shape nested within a similar second shape as a nested shape to identify an item bearing an optical code on a display screen when analyzing the first set of images.

14. A system for data reading according to claim 13, wherein the controller is further programmed to:

determine an average brightness of the first shape when analyzing the first set of images;

determine an average brightness of an area surrounding the first shape when analyzing the first set of images;

compare the average brightness of the first shape against the average brightness of the area surrounding the first shape to determine whether the display screen is backlit when analyzing the first set of images; and

wherein the programming to automatically adjust operating parameters of the imager is further based on whether the display screen is backlit.

15. A system for data reading according to claim 11, further comprising an initial operating parameter set including (i) a baseline gain and exposure duration for the imager and (ii) an illumination setting for the illumination source, and the controller is further programmed to:

if the item is in the recognized item class, establish a secondary operating parameter set to capture a second set of images wherein the secondary operating parameter set includes (i) an increased one or both of a gain and an exposure duration for the imager when compared to the initial operating parameter set and (ii) a decreased illumination setting for the illumination source when compared to the initial operating parameter set; and

if the item is not in the recognized item class, establish the initial operating parameter set to capture a second set of images.

16. A system for data reading according to claim 15 wherein the controller is further programmed to:

establish the secondary operating parameter set to capture a majority of the images and establish the initial operating parameter set to capture a minority of the images if the item is in the recognized item class; and

establish the initial operating parameter set to capture a majority of the images and establish the secondary operating parameter set to capture a minority of the images if the item is not in the recognized item class.

17. A system for data reading according to claim 16 wherein the controller is further programmed to:

establish the secondary operating parameter set to capture about 75% of the images and establish the initial operating parameter set to capture about 25% of the images if the item is in the recognized item class; and

establish the initial operating parameter set to capture about 75% of the images and establish the secondary operating parameter set to capture about 25% of the images if the item is not in the recognized item class.

18. A system for data reading according to claim 11 wherein the controller is further programmed to decode the optical code including automatically attempting to decode a particular type of optical code first based on whether the item is in the recognized item class.

19. A system for data reading according to claim 11 wherein the controller is further programmed to:

analyze the first set of images to identify the item; and

decode the optical code including automatically attempting to decode a particular type of optical code first based on identifying the item.

20. A method for data reading comprising the steps of:

capturing, via a data reader, a first set of images of an item bearing an optical code;

creating a histogram based on the first set of images;

analyzing the histogram to determine whether the histogram is bi-modal;

automatically adjusting operating parameters of the data reader based on whether the histogram is bi-modal;

capturing, via the data reader, a second set of images of the item bearing the optical code using the adjusted operating parameters; and

processing the second set of images to decode the optical code appearing in the second set of images of the item.

21. A method according to claim 20, wherein analyzing the histogram to determine whether the histogram is bi-modal includes:

comparing a first number of pixels against a predetermined grayscale low threshold percentage; and

comparing a second number of pixels against a predetermined grayscale high threshold percentage.

22. A method according to claim 20, wherein processing the second set of images further includes:

creating a second histogram based on the second set of images;

analyzing the second histogram to determine whether the second histogram is bi-modal; and

automatically adjusting operating parameters of the data reader based on whether the second histogram is bi-modal.