US Patent 9767581 Auto-contrast viewfinder for an indicia reader

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.