Granted Patent B2

US 8,493,479 · App. 13/094,973 · Granted Jul 23, 2013

Abstract

Claims (24)

1. A method of eliminating background noise from a system for authenticating security markers comprising:

capturing an image of a background with a security marker;

illuminating the security marker;

capturing a plurality of images of an optical response of the security marker;

averaging the plurality of optical response images;

smoothing the background image; and

subtracting the smoothed background image from the average of the plurality of optical response images.

2. The method of claim 1 comprising:

calculating a score based on the number of pixels above a predetermined threshold; and

authenticating the security marker if the score meets predetermined requirements.

3. The method of claim 1 wherein the images are captured by a CCD or CMOS sensor.

4. The method of claim 1 wherein smoothing the background image comprises applying a median filter on a pixel by pixel basis to the background image.

5. The method of claim 1 wherein averaging the plurality of optical response images comprises:

averaging the corresponding pixels of the plurality of images.

6. A method of eliminating background noise from a system for authenticating security markers comprising:

capturing a plurality of images of a background with a security marker;

averaging the background images;

illuminating the security marker;

capturing a plurality images of an optical response;

averaging the plurality of optical response images;

smoothing the averaged background image; and

subtracting the smoothed background image from the average of the plurality of optical response images.

7. The method of claim 1 wherein averaging the plurality of optical response images comprises:

calculating a resulting image wherein each pixel value is an average of the corresponding pixel values of the plurality of images.

Assignments (21)