公开(公告)号：CA2044404A1

公开(公告)日：1992-02-01

申请号：CA2044404

申请日：1991-06-12

Applicant: XEROX CORP

Inventor： BLOOMBERG DAN S ,  HECHT DAVID L ,  TOW ROBERT F ,  FLORES L PRASADAM

IPC: G06K19/00 ,  G06K7/016 ,  G06K19/06 ,  G06V30/224 ,  G06F15/62 ,  G06F3/12

Abstract: This invention provides self-clocking glyph shape codes for encoding digital data in the shapes of glyphs that are suitable for printing on hardcopy recording media. Advantageously, the glyphs are selected so that they tend not to degrade into each other when they are degraded and/or distorted as a result, for example, of being photocopied, transmitted via facsimile, and/or scanned-in to an electronic document processing system. Moreover, for at least some applications, the glyphs desirably are composed of printed pixel patterns containing nearly the same number of ON pixels and nearly the same number of OFF pixels, such that the code that is rendered by printing such glyphs on substantially uniformly spaced centers appears to have a generally uniform texture. In the case of codes printed at higher spatial densities, this texture is likely to be perceived as a generally uniform gray tone. Binary image processing and convolution filtering techniques for decoding such codes also are diclosed, but this application focuses on the codes.

公开(公告)号：CA2044404C

公开(公告)日：1998-06-23

申请号：CA2044404

申请日：1991-06-12

Applicant: XEROX CORP

Inventor： BLOOMBERG DAN S ,  HECHT DAVID L ,  TOW ROBERT F ,  FLORES L PRASADAM

IPC: G06K19/00 ,  G06K7/016 ,  G06K19/06 ,  G06V30/224 ,  G06F3/12

Abstract: This invention provides self-clocking glyph shape codes for encoding digital data in the shapes of glyphs that are suitable for printing on hardcopy recording media. Advantageously, the glyphs are selected so that they tend not to degrade into each other when they are degraded and/or distorted as a result, for example, of being photocopied, transmitted via facsimile, and/or scanned-in to an electronic document processing system. Moreover, for at least some applications, the glyphs desirably are composed of printed pixel patterns containing nearly the same number of ON pixels and nearly the same number of OFF pixels, such that the code that is rendered by printing such glyphs on substantially uniformly spaced centers appears to have a generally uniform texture. In the case of codes printed at higher spatial densities, this texture is likely to be perceived as a generally uniform gray tone. Binary image processing and convolution filtering techniques for decoding such codes also are diclosed, but this application focuses on the codes.

公开(公告)号：DE3686814T2

公开(公告)日：1993-04-01

申请号：DE3686814

申请日：1986-12-16

Applicant: XEROX CORP

Inventor： SPRAGUE ROBERT A ,  HECHT DAVID L ,  FLORES L PRASADAM

IPC: G02F1/05 ,  G02F1/03 ,  G02F1/315 ,  G06K15/12 ,  B41J2/435 ,  G03G15/30

Abstract: An optical image bar (12) utilizing polarized light and a coherent spatial light modulator (16) includes birefrigent spatial or angular shearing means (51) for uniformly dividing the spatially-modulated output radiation of a coherent image bar into a pair of laterally-offset, redundantly-modulated, orthogonally-polarized optical field distributions. Imaging optics (17), which include any spatial filtering and/or polarization filtering elements needed for converting those field distributions into correspondingly-modulated spatial intensity distributions, bring the filtered field distributions to focus on an output image plane (13), thereby producing redundantly-modulated, laterally-offset, intensity profiles on the output image plane which spatially sum with each other on an intensity basis. The magnitude of the shear is selected so that the image plane offset of those intensity profiles is approximately equal to half the nominal image plane pixel pitch of the image bar, whereby each of the intensity profiles redundantly overwrites the interpixel intensity nulls of the other. Spatial shearing is preferred for image bars having telecentric imaging optics, but angular shearing is a practical alternative for some embodiments.

公开(公告)号：DE69130786T2

公开(公告)日：1999-06-10

申请号：DE69130786

申请日：1991-07-30

Applicant: XEROX CORP

Inventor： BLOOMBERG DAN S ,  HECHT DAVID L ,  TOW ROBERT F ,  FLORES L PRASADAM

IPC: G06K7/016 ,  G06K19/00 ,  G06K19/06 ,  G06V30/224 ,  G06K1/12

Abstract: This invention provides self-clocking glyph shape codes for encoding digital data (35) in the shapes of glyphs (36) that are suitable for printing on hardcopy recording media. Advantageously, the glyphs (36) are selected so that they tend not to degrade into each other when they are degraded and/or distorted as a result, for example, of being photocopied, transmitted via facsimile, and/or scanned-in to an electronic document processing system. Moreover, for at least some applications, the glyphs (36) desirably are composed of printed pixel patterns containing nearly the same number of ON pixels and nearly the same number of OFF pixels, such that the code that is rendered by printing such glyphs (36) on substantially uniformly spaced centers appears to have a generally uniform texture. In the case of codes printed at higher spatial densities, this texture is likely to be perceived as a generally uniform gray tone. Binary image processing and convolution filtering techniques for decoding such codes also are disclosed, but this application focuses on the codes.

公开(公告)号：DE69130786D1

公开(公告)日：1999-03-04

申请号：DE69130786

申请日：1991-07-30

Applicant: XEROX CORP

Inventor： BLOOMBERG DAN S ,  HECHT DAVID L ,  TOW ROBERT F ,  FLORES L PRASADAM

IPC: G06K7/016 ,  G06K19/00 ,  G06K19/06 ,  G06V30/224 ,  G06K1/12

Abstract: This invention provides self-clocking glyph shape codes for encoding digital data (35) in the shapes of glyphs (36) that are suitable for printing on hardcopy recording media. Advantageously, the glyphs (36) are selected so that they tend not to degrade into each other when they are degraded and/or distorted as a result, for example, of being photocopied, transmitted via facsimile, and/or scanned-in to an electronic document processing system. Moreover, for at least some applications, the glyphs (36) desirably are composed of printed pixel patterns containing nearly the same number of ON pixels and nearly the same number of OFF pixels, such that the code that is rendered by printing such glyphs (36) on substantially uniformly spaced centers appears to have a generally uniform texture. In the case of codes printed at higher spatial densities, this texture is likely to be perceived as a generally uniform gray tone. Binary image processing and convolution filtering techniques for decoding such codes also are disclosed, but this application focuses on the codes.

公开(公告)号：DE3686814D1

公开(公告)日：1992-10-29

申请号：DE3686814

申请日：1986-12-16

Applicant: XEROX CORP

Inventor： SPRAGUE ROBERT A ,  HECHT DAVID L ,  FLORES L PRASADAM

IPC: G02F1/05 ,  G02F1/03 ,  G02F1/315 ,  G06K15/12 ,  B41J2/435 ,  G03G15/30

Abstract: An optical image bar (12) utilizing polarized light and a coherent spatial light modulator (16) includes birefrigent spatial or angular shearing means (51) for uniformly dividing the spatially-modulated output radiation of a coherent image bar into a pair of laterally-offset, redundantly-modulated, orthogonally-polarized optical field distributions. Imaging optics (17), which include any spatial filtering and/or polarization filtering elements needed for converting those field distributions into correspondingly-modulated spatial intensity distributions, bring the filtered field distributions to focus on an output image plane (13), thereby producing redundantly-modulated, laterally-offset, intensity profiles on the output image plane which spatially sum with each other on an intensity basis. The magnitude of the shear is selected so that the image plane offset of those intensity profiles is approximately equal to half the nominal image plane pixel pitch of the image bar, whereby each of the intensity profiles redundantly overwrites the interpixel intensity nulls of the other. Spatial shearing is preferred for image bars having telecentric imaging optics, but angular shearing is a practical alternative for some embodiments.

公开(公告)号：JPS62153934A

公开(公告)日：1987-07-08

申请号：JP29978686

申请日：1986-12-16

Applicant: XEROX CORP

Inventor： SPRAGUE ROBERT A ,  HECHT DAVID L ,  FLORES L PRASADAM

IPC: G02F1/05 ,  G02F1/03 ,  G02F1/315 ,  G06K15/12