AUTO-CONTRAST VIEWFINDER FOR AN INDICIA READER

• US 20160171720A1
• Filed: 12/12/2014
• Published: 06/16/2016
• Est. Priority Date: 12/12/2014
• Status: Active Grant

• Current Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Original Assignee: Hand Held Products Incorporated (Honeywell International Inc.)
• Inventors: Todeschini, Erik
• Granted Patent: US 9,767,581 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06T 11/001 Texturing; Colouring; Generation of texture or colour inpainting G06T5/77

Abstract

Viewfinders for indicia-readers and/or mobile devices running indicia reading applications allow a user to position the reader with respect to the indicia. A display presents a real-time image of the camera as a background, while simultaneously presenting a graphical overlay that is superimposed on the background. The graphical overlay provides a user messages via text or graphics. Choosing a single color for the messages on the graphical overlay can lead to visibility problems in some imaging scenarios. The present invention provides a method and device to provide automatic contrast adjustment of these message based on the image characteristics beneath or around each message in order to maintain visibility in all imaging scenarios.

Claims

1. A method for improving the visibility of a graphical overlay in a barcode scanning application running on a mobile device configured with a camera, the method comprising:

capturing an image of a field of view with the camera;

rendering a graphical overlay comprising a message on a transparent background, the message covering a specific message area in the image beneath it when the graphical overlay is superimposed on the image;

analyzing the message area to derive an image metric;

adjusting the pixel values of the message based on the image metric; and

displaying the graphical overlay superimposed on the image on the mobile device'"'"'s display.

2. The method according to claim 1, wherein the graphical overlay comprises a plurality of messages, each message covering a unique message area, and each message adjusted individually based on its own unique image metric.

3. The method according to claim 1, wherein the steps of rendering , analyzing, adjusting, and displaying are repeated for each image in a real-time video stream of images.

4. The method according to claim 1, wherein the message comprises text.

5. The method according to claim 1, wherein the message comprises a single-colored graphic.

6. The method according to claim 1, wherein the image metric comprises a quantified value related to the image'"'"'s intensity and/or color in the message area.

7. The method according to claim 1, wherein the pixel values of the message comprise an RGB color.

8. The method according to claim 1, wherein the image metric comprises an average pixel intensity over the message area.

9. The method according to claim 8, wherein the step of adjusting comprises:

comparing the image metric to a threshold; and

when the image metric exceeds the threshold then adjusting the message'"'"'s pixel values to a minimum intensity, or

when the image metric does not exceed the threshold then adjusting the message'"'"'s pixel values to a maximum intensity.

10. A mobile device comprising:

a camera for capturing images of a field of view;

a display for displaying (i) images from the camera and (ii) a graphical overlay superimposed on the images, the graphical overlay comprising a message;

a memory for storing an indicia-reading application; and

a processor configured by the indicia-reading application (i) to analyze the pixel characteristics in areas surrounding the message, and (ii) to adjust a color of the message to improve the message'"'"'s visibility.

11. The mobile device according to claim 10, wherein the images comprise a real-time video stream of image frames.

12. The mobile device according to claim 10, wherein the graphical overlay comprises a plurality of messages on a transparent background.

13. The mobile device according to claim 10, wherein the message comprises text.

14. The mobile device according to claim 10, wherein the message comprises a single color graphic.

15. The mobile device according to claim 10, wherein the pixel characteristics comprise an average pixel intensity.

16. The mobile device according to claim 10, wherein the pixel characteristics comprise an average color.

17. The mobile device according to claim 10, wherein the area surrounding a message comprises a message area and a margin area, wherein

the message area comprises a rectangular area of pixels containing only the message, and

the margin area comprises a frame of pixels surrounding the message area.

18. The mobile device according to claim 17, wherein the margin area is zero.

19. An imaging barcode scanner comprising:

a camera module for capturing images of a field of view; and

a viewfinder module for displaying real-time images from the camera overlaid with messages, wherein the viewfinder module changes the color characteristics of the messages in response to color characteristics of the images.

20. The imaging barcode scanner according to claim 19, wherein the images comprise a video stream of images and the color characteristics of the graphical messages change in real time.

21. The imaging barcode scanner according to claim 19, wherein changing the color characteristics of the messages comprises changing the color of each message to contrast maximally with the color of the image behind each message respectively.

22. The imaging barcode scanner according to claim 19, wherein the messages comprise an aiming graphic to help a user align a barcode.