Optical reader
First Claim
Patent Images
1. An optical reader for reading high density dibit encoded data from a data strip, said optical reader comprising:
- an optical detector; and
means, connected to said optical detector, for decoding an output from said optical detector, said optical detector including photo-sensitive means arranged to extend transversely across a row of dibits thereby to form an image of said row of dibits, and said means connected to said optical detector including;
buffer means for storing said image of said row of dibits andimage transform means, operatively connected to said buffer means, for detecting a skew angle of said reader relative to said data strip and for applying a shear transformation to said image of said row of dibits stored in said buffer means thereby compensating for distortion of said image in accordance with said skew angle.
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Abstract
An optical reader for reading high density dibit encoded data from a data strip comprises an optical detector (13) and a detector (14,15,DSP) connected to the optical detector (13) and arranged to decode its output. The detector includes a row of photosensitive elements arranged to extend transversely across a row of dibits and to form an image of the row of dibits. The decoder (14,15,DSP) includes a buffer (15) arranged to store the row image. An image transform device detects a skew angle of the strip and transforms the stored image to compensate for the distortion of the image.
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Citations
12 Claims
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1. An optical reader for reading high density dibit encoded data from a data strip, said optical reader comprising:
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an optical detector; and means, connected to said optical detector, for decoding an output from said optical detector, said optical detector including photo-sensitive means arranged to extend transversely across a row of dibits thereby to form an image of said row of dibits, and said means connected to said optical detector including; buffer means for storing said image of said row of dibits and image transform means, operatively connected to said buffer means, for detecting a skew angle of said reader relative to said data strip and for applying a shear transformation to said image of said row of dibits stored in said buffer means thereby compensating for distortion of said image in accordance with said skew angle. - View Dependent Claims (2)
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3. An optical reader for reading high density dibit encoded data from a data strip, said optical reader comprising:
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an optical detector; and means, connected to said optical detector, for decoding an output from said optical detector, said optical detector including photo-sensitive means arranged to extend transversely across a row of dibits thereby to form an image of said row of dibits, and said means connected to said optical detector including; buffer means for storing said image of said row of dibits and image transform means, operatively connected to said buffer means, for detecting a skew angle of said reader relative to said data strip and for applying a shear transformation to said image of said row of dibits stored in said buffer means thereby compensating for distortion of said image in accordance with said skew angle, wherein said image transform means include an image resampling sequencer for receiving image data from said buffer means and applying to said image data a transform;
space="preserve" listing-type="equation">Y=V.sub.o +Aueach point (u,v) in the raw data thereby being mapped to (X,Y) in the transformed data, where (u,v) and (X,Y) are lateral and longitudinal coordinates of raw image data stored in said buffer means and transformed image data respectively, where Y is as defined above and X=u. - View Dependent Claims (4, 5)
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6. An optical reader for reading high density dibit encoded data from a data strip, said optical reader comprising:
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an optical detector; and means, connected to said optical detector, for decoding an output from said optical detector, said optical detector including photo-sensitive means arranged to extend transversely across a row of dibits thereby to form an image of said row of dibits, and said means connected to said optical detector including; buffer means for storing said image of said row of dibits; and image transform means, operatively connected to said buffer means, for detecting a skew angle of said reader relative to said data strip and for applying a shear transformation to said image of said row of dibits stored in said buffer means thereby compensating for distortion of said image in accordance with said skew angle, further comprising an A/D converter for digitizing signals from said optical detector and for providing an output to said buffer means, and means for detecting a reference output by said optical detector and for setting a reference voltage for said A/D converter accordingly.
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7. A hand-held optical reader for reading high density dibit encoded data from a data strip comprising:
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an optical detector for imaging successive rows of dibits as said reader is moved along said data strip in contact with said strip, a light source offset from a region of contact between said reader and said strip and arranged to illuminate said region of contact, means connected to said optical detector for decoding an output from said optical detector, buffer means for storing an output from said detector image, and image transform means for detecting a skew angle of said reader relative to said strip and for applying a shear transformation to said image of said row of dibits stored in said buffer means, thereby to compensate for distortion of said image in accordance with said skew angle. - View Dependent Claims (8)
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9. A hand-held optical reader for reading high density dibit encoded data from a data strip comprising:
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an optical detector for imaging successive rows of dibits as said reader is moved along said data strip in contact with said strip, a light source offset from a region of contact between said reader and said strip and arranged to illuminate said region of contact, means connected to said optical detector for decoding an output from said optical detector, buffer means for storing an output from said detector image, and image transform means for detecting a skew angle of said reader relative to said strip and for applying a shear transformation to said image of said row of dibits stored in said buffer means, thereby to compensate for distortion of said image in accordance with said skew angle, wherein said image transform means include an image resampling sequencer for receiving image data from said buffer means and applying to said image data a transform;
space="preserve" listing-type="equation">Y=V.sub.o +Aueach point (u,v) in the raw data thereby being mapped to (X,Y) in the transformed data, where (u,v) and (X,Y) are lateral and longitudinal coordinates of raw image data stored in said buffer means and transformed image data respectively, where Y is as defined above and X=u. - View Dependent Claims (10, 11)
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12. A hand-held optical reader for reading high density dibit encoded data from a data strip comprising:
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an optical detector for imaging successive rows of dibits as said reader is moved along said data strip in contact with said strip, a light source offset from a region of contact between said reader and said strip and arranged to illuminate said region of contact, means connected to said optical detector for decoding an output from said optical detector, buffer means for storing an output from said detector image, and image transform means for detecting a skew angle of said reader relative to said strip and for applying a shear transformation to said image of said row of dibits stored in said buffer means, thereby to compensate for distortion of said image in accordance with said skew angle, further comprising an A/D converter for digitizing signals from said optical detector and for providing an output to said buffer means, and means for detecting a reference output by said optical detector and for setting a reference voltage for said A/D converter accordingly.
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Specification