Detection of barcodes in binary images with arbitrary orientation
First Claim
1. A method of determining the location of a barcode block having a predetermined size and shape on a document having extraneous printed matter thereon comprising:
- receiving a digital image of a scanned document as an input signal;
reducing the input signal to produce a first down-sampled image that is over-sampled;
reducing the input signal to produce a second down-sampled image that is under-sampled;
deleting barcode image pixels from the under-sampled image to produce a barcode free image;
subtracting the barcode free image from the over-sampled image to produce an image definitely showing the barcode block location but not showing large sized background clutter that is common to the barcode free image and the over-sampled image; and
down-sampling the barcode block location containing image and thereafter removing small sized background clutter thereby to produce an image showing the barcode block location which is substantially free of background clutter.
1 Assignment
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Accused Products
Abstract
The location and orientation of a barcode block is determined by first producing an image of the document that excludes the barcode block and producing a second image wherein the spaces in the barcode block have been deleted thereby providing a solid rectangular block. The two images are subtracted to reject large background clutter while displaying with certainty the full image of the barcode block. Thereafter, down-sampling occurs to remove small clutter and other non-barcode objects while locating the centroid of each barcode block. The image containing the centroid is up-scaled and used to calculate the position of the barcode block in the original document for use by a barcode reader.
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Citations
13 Claims
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1. A method of determining the location of a barcode block having a predetermined size and shape on a document having extraneous printed matter thereon comprising:
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receiving a digital image of a scanned document as an input signal; reducing the input signal to produce a first down-sampled image that is over-sampled; reducing the input signal to produce a second down-sampled image that is under-sampled; deleting barcode image pixels from the under-sampled image to produce a barcode free image; subtracting the barcode free image from the over-sampled image to produce an image definitely showing the barcode block location but not showing large sized background clutter that is common to the barcode free image and the over-sampled image; and down-sampling the barcode block location containing image and thereafter removing small sized background clutter thereby to produce an image showing the barcode block location which is substantially free of background clutter. - View Dependent Claims (2, 3)
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4. A method of determining the location of all barcode blocks having a predetermined size and shape on a background area that is scanned to produce an image of the area in a data format comprising the steps of:
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reducing input image data into two down-sampled images, one being under-sampled and the other being over-sampled; modifying the two down-sampled images so that an image of each barcode block is positively provided in a third image and positively not present in a fourth image; subtracting the fourth image from the third image to produce a fifth image that contains the barcode block and unwanted small clutter but is free of clutter present in both the third and fourth images; and thereafter removing the unwanted small clutter from the fifth image to provide a sixth image containing only the barcode block. - View Dependent Claims (5)
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6. A method of detecting the location of a barcode having a predetermined size and polygonal shape on a background containing printed matter for subsequent reading of the barcode comprising:
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reducing by a first reduction factor input image data of the background and barcode to produce a first over-sampled image and a second under-sampled image; removing all pixels that form the barcode by morphological erosion from the under-sampled image to produce a modified under-sampled image; connecting all bars in a barcode into a single area having said polygonal shape by morphological dilation from the over-sampled image to produce a modified over-sampled image; and subtracting said modified under-sampled image from the modified over-sampled image to produce a new image that contains the barcode shape at its position on the background, said new image being free of large size clutter that is part of both the under-sampled image and the over-sampled image. - View Dependent Claims (7, 8, 9)
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10. A method of reducing clutter from a document image containing printed matter including at least one barcode having dark bars and blank spaces in a configuration having a predetermined shape and area comprising:
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generating a pixel based image of said at least one barcode in a data generated pixel based image of the document in which printed matter appears as objects and all bars of the barcode appear as an object comprised of a solid bar without spaces and having said predetermined shape; forming a table of said objects in said pixel based image including at least one barcode and clutter, each of said objects having an area with the object area being defined by the number of pixels in the area; and eliminating from the pixel based image all objects which have a number of pixels that differs by more than a predetermined amount from the number of pixels in the area of a genuine barcode image. - View Dependent Claims (11, 12, 13)
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Specification