Adaptive tracking of dots in optical storage system using ink dots

• US 6,542,645 B1
• Filed: 07/10/1998
• Issued: 04/01/2003
• Est. Priority Date: 07/15/1997
• Status: Expired due to Term

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Walmsley, Simon Robert, Silverbrook, Kia
• Primary Examiner(s): Lee, Thomas D.
• Application Number:
  US09/113,059
• Time in Patent Office: 1,726 Days
• Field of Search: 382/254, 382/309, 358/455, 358/456, 358/457, 358/458, 358/430, 358/1.9, 235/437
• US Class Current: 382/254
• CPC Class Codes: B41J 2/14 Structure thereof only for on-demand ink jet heads
• CPC Class Codes: B41J 2/16585 for paper-width or non-reciprocating print heads
• CPC Class Codes: B41J 2/17513 Inner structure
• CPC Class Codes: B41J 2/17596 Ink pumps, ink valves
• CPC Class Codes: B41J 2002/041 Electromagnetic transducer
• CPC Class Codes: B41J 2202/21 Line printing
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G06F 21/79 in semiconductor storage media, e.g. directly-addressable memories
• CPC Class Codes: G06F 21/86 Secure or tamper-resistant housings
• CPC Class Codes: G06F 2221/2129 Authenticate client device independently of the user
• CPC Class Codes: G06K 1/121 by printing code marks applying code marks to labels B65C9/46; marking or coding completed packages B65B61/26
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G06K 7/1417 2D bar codes
• CPC Class Codes: G11C 11/56 using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
• CPC Class Codes: H04N 1/00326 with a data reading, recognizing or recording apparatus, e.g. with a bar-code apparatus arrangements for the associated working of recording or reproducing apparatus with related apparatus G11B31/00
• CPC Class Codes: H04N 1/0044 for image preview or review, e.g. to help the user position a sheet
• CPC Class Codes: H04N 1/00965 using a plug-in memory module, e.g. memory card, memory stick
• CPC Class Codes: H04N 1/2112 using still video cameras
• CPC Class Codes: H04N 1/2154 the still video camera incorporating a hardcopy reproducing device, e.g. a printer
• CPC Class Codes: H04N 1/32101 : Display, printing, storage or transmission of additional information, e.g. ID code, date and time or title
• CPC Class Codes: H04N 1/32133 : on the same paper sheet, e.g. a facsimile page header
• CPC Class Codes: H04N 2101/00 : Still video cameras
• CPC Class Codes: H04N 2201/3222 : of processing required or performed, e.g. forwarding, urgent or confidential handling
• CPC Class Codes: H04N 2201/3269 : of machine readable codes or marks, e.g. bar codes or glyphs
• CPC Class Codes: H04N 2201/3276 : of a customised additional information profile, e.g. a profile specific to a user ID
• CPC Class Codes: H04N 2201/328 : Processing of the additional information
• CPC Class Codes: H04N 23/00 : Cameras or camera modules comprising electronic image sensors; Control thereof
• CPC Class Codes: H04N 5/2628 : Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

A method of accurately determining the location of dots of sensed image data amongst an array of dots of image data in a fault tolerant manner, said data stored at a high pitch rate on a card and subject to rotations, warping and marking effects, said method comprising the steps of:

processing the image data in a column by column format;

recording the dot pattern of previously processed columns of pixels;

generating an expected dot pattern at a current column position from the recorded dot pattern of previously processed pixels;

comparing the expected dot pattern with an actual dot pattern of sensed image data at said current column position;

if said comparison produces a match within a predetermined error, utilising said current column position as an actual dot position otherwise altering said current column position to produce a better fit to said expected dot pattern to thereby produce new actual dot position, and

utilizing said actual dot position of the dot at a current column position in the determining of dot location of dots of subsequent columns.

Claims

1. A method of accurately determining the location of dots of image data amongst an array of dots of image data in a fault tolerant manner, said data stored at a high pitch rate on a card subject to rotations, warping and marking effects, said method comprising the steps of:

sensing and processing the image data column by column;

recording the dot pattern of previously processed columns of pixels;

generating an expected dot pattern at a current position of a column of pixels from the recorded dot pattern of previously processed pixels;

comparing the expected dot pattern with an actual dot pattern of sensed image data at said current position of a column of pixels;

if said comparison produces a match within a predetermined error, utilising said current position of a column of pixels as an actual dot position otherwise altering said current position of a column of pixels to produce a better fit to said expected dot pattern to thereby produce new actual dot position, and utilising said actual dot position of the dot at a current position of a column of pixels in the determining of dot location of dots of subsequent columns of pixels.

2. A method as claimed in claim 1 wherein said actual dot position is stored in the form of a difference between an expected dot position and a recorded actual dot position.

3. A method as claimed in claim 1 wherein said expected dot pattern is derived from previously recorded dot patterns for a current row of said current position of a column of pixels.

4. A method as claimed in claim 3 wherein said sensed image data is supersampled at a rate of substantially three times the dot pitch rate and said expected dot pattern comprises a 20 bit pattern corresponding to the intensities sensed along said current row.

5. A method as claimed in claim 3 wherein said method is repeated for a current column of said current position of a column of pixels.

6. A method as claimed in claim 1 wherein said expected dot position is recorded in the form of differential column and row components.