Imaging engine and method for code readers
First Claim
Patent Images
1. An imaging and aiming apparatus for an optical code reader comprising:
- an image sensor, including an array of photo sensor cells for producing electronic signals corresponding to a two-dimensional array of pixel information for a target image;
a lens assembly for focusing light incident on the reader from at least two different fields of view, corresponding to at least two different focal distances;
means for controlling the lens assembly to select a field of view; and
an aiming pattern projector for projecting at least two different aiming frames, each indicating a field of view of the lens assembly.
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Abstract
An imaging engine and signal processing devices and methods are disclosed for reading various kinds of optical codes. The compact structure may include a two dimensional image sensor, apparatus for focusing images at different focal disclosures, an aiming system, a hi-low beam illumination system and related signal processing circuits.
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Citations
52 Claims
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1. An imaging and aiming apparatus for an optical code reader comprising:
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an image sensor, including an array of photo sensor cells for producing electronic signals corresponding to a two-dimensional array of pixel information for a target image;
a lens assembly for focusing light incident on the reader from at least two different fields of view, corresponding to at least two different focal distances;
means for controlling the lens assembly to select a field of view; and
an aiming pattern projector for projecting at least two different aiming frames, each indicating a field of view of the lens assembly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
snap fitting means for aligning the lens elements along a common optical axis in back-to-back relationship.
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18. An imaging engine for a handheld optical code reader for reading optical codes located at various distances from the imaging engine comprising:
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a solid state device for producing a signal corresponding to a two-dimensional image, a solid state device lens assembly having a principal input optical axis for focusing light on the solid state device, said lens assembly being switchable between at least two different focal distances;
an optical element for projecting an aiming pattern in a field of view of the solid state device lens assembly, the pattern having an angular dimension related to the size of the fields of view of the solid state device lens assembly at the at least two different focal distances;
an illumination source which is switchable to provide a first illumination field adapted to illuminate a target code at one of said focal distances and a second illumination field adapted to illuminate a target code at another of said focal distances;
decoding circuitry for selecting a portion of an image of the field for decoding; and
control circuitry for switching said solid state device lens assembly and illumination source.
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19. An imaging lens system for a solid state device optical code reader comprising:
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an imaging lens assembly having a first angular field of view and a second angular field of view, wherein the lens assembly includes two objective lenses and switching means including mirror selectively positionable in a beam path of the solid state device to provide incident light from said first or said second lenses to the solid state device; and
means for rapidly switching between said first and said second fields of view in response to detected distance between the reader and a target barcode, at which the reader is aimed. - View Dependent Claims (20, 21)
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22. An optical code reader comprising:
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a solid state device imaging system having at least two different fields of view;
a laser; and
a diffractive optical element for diffracting light from the laser and producing at least two different aiming pattern frames corresponding to the at least two different scanning fields of the solid state device imaging system. - View Dependent Claims (23, 24)
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25. An optical code reader comprising:
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a solid state device imaging system having at least one field of view;
an aiming pattern projector for projecting an aiming pattern in the direction of a target barcode;
a means for decoding a target optical code located in a field of view of the solid state device imaging system; and
means for locating at least a portion of an aiming pattern in an image produced by the solid state device imaging system and for providing feedback to the decoding means to identify an image area in which the target barcode is located. - View Dependent Claims (26, 27, 28, 29, 30, 31)
a switchable illumination source; and
means for analyzing the position of the center marker relative to the field of view of the reader to select an illumination level for a subsequent image to be decoded.
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30. The optical code reader of claim 28, further comprising means for analyzing the position of the center marker relative to the field of view of the reader to select an exposure level for a subsequent image to be decoded.
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31. The optical code reader of claim 28, further comprising:
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means for changing the focal distance of the CCD imaging system, and means for analyzing the position of the center marker relative to the field of view of the reader to select a focal distance for a subsequent image to be decoded.
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32. A method for reading a target barcode comprising:
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projecting an aiming pattern from a handheld optical code reader in the direction of the target barcode;
producing a signal corresponding to a two dimensional image with a field including at least a portion of the aiming pattern and the target barcode;
identifying the location of at least a portion of the pattern within the two-dimensional image; and
selecting a portion of an image of the field for decoding, relative to the identified location. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40)
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41. An apparatus for determination of the distance between an imaging engine and a target barcode comprising:
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means for projecting an aiming pattern from an optical code reader in the direction of the target barcode, said aiming pattern having a principal optical axis;
electro-optical means for producing a signal corresponding to a two dimensional image with a field including at least a portion of the aiming pattern and the target barcode, wherein the electro-optical means has a principal optical axis generally parallel and offset from the principal optical axis of the projecting means; and
means for locating at least a portion of the aiming pattern within a two dimensional image detected by said electro-optical means and for producing a signal corresponding to the distance between the imaging engine and the target barcode based on the location of the position of the at least a portion of the aiming pattern. - View Dependent Claims (42, 43)
a lens assembly means being switchable between at least two different focal distances; and
an illumination means which is switchable to provide a first illumination field adapted to illuminate the target barcode at one of the focal distances and a second illumination field adapted to illuminate the target barcode at another of the focal distances.
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44. A target illumination source for a handheld optical code reader comprising:
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means for producing a broad beam of low output intensity to illuminate a target barcode close to the optical code reader; and
means for producing a narrower beam of higher output intensity to illuminate a target barcode far from the optical code reader. - View Dependent Claims (45, 46, 47, 48)
wherein the means for producing the higher output intensity illumination beam is one or more light emitting elements with a narrow divergence pattern located relatively farther from a principal optical axis of the reader.
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47. The illumination source of claim 44, wherein the means for producing the higher intensity, relatively narrower illumination beam is plural light emitting diodes each associated with a focusing lenslet located in a front face of the reader.
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48. The illumination source of claim 44,
wherein the beam producing means are plural light emitting elements, which emit light from a forward face of the reader; - and further comprising
an image sensor for producing electronic signals corresponding to a two dimensional array of pixel information for a field view; and
image processing means for compensating said signals for known variations in illumination of the beam producing means.
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49. A method for determining a distance between an imaging engine and a target barcode comprising the steps of:
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projecting an aiming pattern from an optical code reader in a direction of the target barcode, the aiming pattern having a principal optical axis;
producing, by electro-optical means, a signal corresponding to a two dimensional image with a field including at least a portion of the aiming pattern and the target barcode, wherein the electro-optical means has a principal optical axis generally parallel and offset from the principal optical axis of the aiming pattern; and
locating at least a portion of the aiming pattern within the two dimensional image; and
generating a signal corresponding to the distance between the imaging engine and the target barcode based on the location of the position of the at least a portion of the aiming pattern.
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50. A method for determining a distance between an imaging engine and a target barcode comprising the steps of:
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projecting a first and second aiming pattern from an optical code reader in the direction of the target barcode, wherein the first and second aiming patterns are associated with a first and second focal distance;
capturing an image of the first and second aiming patterns;
correlating an offset between the first projected aiming pattern and the second projected aiming pattern with the first and second focal distances;
calibrating the imagining engine using said correlation;
illuminating the target barcode using either the first or second aiming pattern; and
determining a distance of the between the imaging engine and the target barcode using an offset of a portion of either the first or second aiming pattern. - View Dependent Claims (51)
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52. An apparatus for determining a distance between a barcode reader and a target barcode comprising:
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means for projecting a first aiming pattern onto a first target plane and for projecting a second aiming pattern onto a second target plane, wherein a portion of the first aiming pattern is offset from a portion of the second aiming patterns with respect to an axis;
means for correlating the offset of the portion of the first aiming pattern with a distance of the first target plane and for correlating the offset of the portion of the second aiming pattern with a distance of the second target plane; and
means for determining the distance between the barcode reader and the target barcode as a function of an offset of a portion of either the first or second aiming patterns.
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Specification