Method and apparatus for scanning electronic barcodes
First Claim
Patent Images
1. A scanner for reading computer-readable codes, the scanner comprising:
- an imaging camera configured to produce an image of a computer-readable code from a surface;
a shroud at least partially surrounding the imaging camera and configured to exclude ambient light from entering the imaging camera when the scanner is held against the surface; and
an illumination lamp disposed within the shroud to illuminate the computer-readable code at an angle such that light from the illumination lamp is not directly reflected from the surface to the imaging camera.
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Abstract
A scanner is provided that can read two-dimensional barcodes from reflective or emissive electronic displays. Illumination, exposure, and contrast can be automatically adjusted according to the type of display and variations in brightness or reflectivity. The scanner includes an imaging camera with high spectral response for reading from color displays. The scanner can also adapt to read barcodes from displays with non-square pixels.
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Citations
27 Claims
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1. A scanner for reading computer-readable codes, the scanner comprising:
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an imaging camera configured to produce an image of a computer-readable code from a surface;
a shroud at least partially surrounding the imaging camera and configured to exclude ambient light from entering the imaging camera when the scanner is held against the surface; and
an illumination lamp disposed within the shroud to illuminate the computer-readable code at an angle such that light from the illumination lamp is not directly reflected from the surface to the imaging camera. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A scanner for reading computer-readable codes, the scanner comprising:
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an imaging camera configured to produce an image of a computer-readable code from a surface;
a shroud at least partially surrounding the imaging camera and configured to exclude ambient light from entering the imaging camera when the scanner is held against the surface and to hold the imaging camera in a selected relation to the surface;
a photodiode disposed within the shroud; and
an illumination lamp disposed within the shroud beyond, relative to the imaging camera, a limit line extending from an edge of a imaging region at an angle of inverse tangent s/2 d wherein s is one-half the width of the imaging region and d is the distance of the camera from the surface..
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10. A method of scanning an image of computer-readable code from an electronic display, the method comprising:
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providing a scanner with a photodetector and an illumination lamp in the off condition, then;
measuring light from the electronic display with the photodetector, and, if the measured light is below a selected threshold;
turning on the illumination lamp; and
scanning the image of the computer-readable code from the electronic display. - View Dependent Claims (11, 12, 13, 14, 17, 18, 19, 20)
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15. A computer-readable medium having computer-executable instructions for performing a method comprising:
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measuring light from an electronic display with a photodetector, and, if the measured light is below a selected threshold;
turning on an illumination lamp; and
scanning a computer-readable code from the electronic display.
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16. A method of scanning a barcode from an electronic display with an imaging scanner, the method comprising:
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measuring a refresh period of the electronic display;
setting an exposure time of the imaging scanner according to the measured refresh period.
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21. A method of scanning a barcode from an electronic display with an imaging scanner, the method comprising:
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capturing a first image of the barcode;
evaluating the first image for an exposure level;
adjusting an exposure parameter of the imaging scanner according to the exposure level;
capturing a second image of the barcode;
attempting to decode the second image to obtain barcode information, and if the attempting step fails;
measuring a refresh period of the electronic display;
setting an exposure time of the imaging scanner according to the measured refresh period;
capturing a third image of the barcode; and
decoding the third image to obtain barcode information.
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22. A computer-readable medium having computer-executable instructions for performing a method of:
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measuring a refresh period of an emissive electronic display;
setting an exposure time of an imaging scanner according to the measured refresh period; and
imaging a barcode displayed on the emissive electronic display. - View Dependent Claims (25)
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23. A method of scanning an image of a barcode displayed on an electronic display with non-square pixels, the method comprising:
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capturing the image of the barcode displayed on the electronic display;
digitizing the image to create a digitized image;
providing the digitized image to a processor;
determining an aspect ratio of a barcode element, and, if the aspect ratio is outside of preselected limits;
scaling the digitized image to create a scaled virtual image with scaled barcode elements having aspect ratios within the preselected limits; and
decoding the scaled virtual image to obtain barcode information.
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24. A method of scanning an image of a barcode displayed on an electronic display, the method comprising:
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capturing the image of the barcode displayed on the electronic display;
digitizing the image to create a digitized image;
providing the digitized image to a processor;
digitally filtering interference patterns from the digitized image to create a filtered image; and
decoding the filtered image to obtain barcode information.
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26. A method of scanning an image of a barcode displayed on an electronic display, the method comprising:
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evaluating the electronic display to determine if the electronic display is an emissive display;
capturing a first image of the barcode with an imaging scanner;
evaluating an exposure level to determine if the exposure level is within preselected exposure level limits, and, if the exposure level is not within the preselected exposure level limits;
adjusting an exposure parameter of the imaging scanner;
capturing a second image of the barcode with the imaging scanner; and
decoding the second image of the barcode to obtain barcode information.
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27. A method of scanning an image of a barcode displayed on an electronic display, the method comprising:
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evaluating the electronic display to determine if the electronic display is an emissive display;
capturing a first image of the barcode with an imaging scanner;
evaluating an exposure level to determine if the exposure level is within preselected exposure level limits, and, if the exposure level is not within the preselected exposure level limits;
adjusting an exposure parameter of the imaging scanner;
capturing a second image of the barcode with the imaging scanner;
attempting to decode the second image to obtain barcode information, and, if the attempt to decode fails;
measuring the electronic display for flickering;
determining a flicker period;
setting an exposure time according to the flicker period;
capturing a third image of the barcode with the imaging scanner; and
decoding the third image to obtain barcode information.
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Specification