Hand-held data capture system with interchangable modules including autofocusing data file reader using the slope of the image signal to determine focus
First Claim
1. A method of reading optical information over a substantial range of distances, comprising:
- (a) reflecting a fan light beam from an object having an image to be focused;
(b) optically directing the image of said reflected light beam such that said light beam impinges on the surface of a photosensitive array;
(c) determining both (1) the variation of a particular data value against the mean value of the surrounding data values of the output of said photosensitive array so as to allow reading of poorly illuminated and partially obscured optical information sets, and (2) the rate of intensity change with respect to time from the output of said photosensitive array; and
(d) focusing said image according to the output of said photosensitive array.
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Accused Products
Abstract
The present invention provides a novel hand-held data capture system with interchangeable modules including an autofocusing data file image reader. Several exemplary modules having various features are described. For example the invention teaches an apparatus and method for providing an interchangeable RF module, an interchangeable reflected image reader, two exemplary interchangeable non-scanning laser illuminated bar code reader/RF modules, and three exemplary interchangeable long range CCD reader/RF modules. Also disclosed for the described modular system are noise filtering means, a solid state laser illumination system, signal processing means, and filter, exposure control, and depth of field control means. An exemplary autofocusing system adjusts the lens to a position where the intensity change with respect to time or with respect to position is maximized. A novel focusing system employs several signal processing algorithms, including a method whereby the maximum slope of the intensity of the image signal with respect to time or with respect to position is determined. Mathematical operations may be performed by a high performance digital signal coprocessor.
144 Citations
33 Claims
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1. A method of reading optical information over a substantial range of distances, comprising:
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(a) reflecting a fan light beam from an object having an image to be focused; (b) optically directing the image of said reflected light beam such that said light beam impinges on the surface of a photosensitive array; (c) determining both (1) the variation of a particular data value against the mean value of the surrounding data values of the output of said photosensitive array so as to allow reading of poorly illuminated and partially obscured optical information sets, and (2) the rate of intensity change with respect to time from the output of said photosensitive array; and (d) focusing said image according to the output of said photosensitive array. - View Dependent Claims (2, 3, 4, 5)
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6. An apparatus for reading optical information over a substantial range of distances, comprising:
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(a) means for reflecting a fan light beam from an object having an image to be focused; (b) means for optically directing the image of said reflected light beam such that said light beam impinges on the surface of a photosensitive array; (c) means for processing the output of said photosensitive array such that the rate of intensity change with respect to time is determined; (d) means for determining the variation of a particular data value stored at a location in the output of said photosensitive array from the mean value of the surrounding locations so as to allow poorly illuminated and partially obscured optical information sets to be read; and (d) means for focusing said image according to the output of said photosensitive array. - View Dependent Claims (7)
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8. A focusing system for a bar code reader, comprising:
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(a) means for emitting a light beam, such that said light beam is reflected from a surface of a bar code; (b) receiving means for receiving said reflected light beam; (c) means for converting said reflected light beam into an electrical signal defining a signal level with respect to time; (d) focusing means for adjusting the focus of the image to change the image reflected onto the receiving means; (e) means for measuring a rate of image intensity with respect to time based on the electrical signal produced; (f) means for determining the variation of a particular data value stored at a location in the output of said photosensitive array from the mean value of the surrounding locations so as to allow poorly illuminated and partially obscured optical information sets to be read; and (g) computer means for sequentially, (1) using said measuring means to produce a first electrical signal corresponding to a first position of said focusing means, (2) adjusting said focusing means to produce a subsequent electrical signal corresponding to said subsequent position of said focusing means, (3) comparing said first electrical signal to said subsequent electrical signal, (4) determining which of said first and subsequent signals represents a faster rate of intensity change with respect to time, and (5) adjusting said focusing means toward the position which produced said faster rate of intensity change with respect to time. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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Specification