Encoded data card reading system

• US 6,315,200 B1
• Filed: 07/10/1998
• Issued: 11/13/2001
• Est. Priority Date: 12/16/1997
• 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): Hajec, Donald
• Assistant Examiner(s): FRECH, KARL D
• Application Number:
  US09/112,784
• Time in Patent Office: 1,222 Days
• Field of Search: 235/462.1, 235/462.24, 235/462.27, 235/462.11, 235/462.01, 235/470
• US Class Current: 235/454
• 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 7/08 by means detecting the change of an electrostatic or magnetic field, e.g. by detecting change of capacitance between electrodes
• 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 2101/00 Still video cameras
• 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 data structure is disclosed encoded on the surface of an object comprising a series of block data regions with each of the block data regions including: an encoded data region containing data to be decoded in an encoded form; a series of clock marks structures located around a first peripheral portion of the encoded data region; and a series of easily identifiable target structures located around a second peripheral portion of the encoded data region. The block data regions can further include an orientation data structure located round a third peripheral portion of the encoded data region. The orientation data structure can comprises a line of equal data points along an edge of the peripheral portion. The clock marks structures can include a first line of equal data points in addition to a substantially adjacent second line of alternating data points located along an edge of the encoded data region. The clock mark structures can be located on mutually opposite sides of the encoded data region. The target structures can comprise a series of spaced apart block sets of data points having a substantially constant value of a first magnitude except for a core portion of a substantially opposite magnitude to the first magnitude. The block sets can further includes a target number indicator structure comprising a contiguous group of the values of the substantially opposite magnitude. The data structure is ideally utilized in a series of printed dots on a substrate surface.

Claims

1. A data structure encoded on the surface of an object comprising:

a series of block data regions with each of said block data regions including;

an encoded data region containing data to be decoded in an encoded form;

a series of clock marks structures located around a first peripheral portion of said encoded data region;

a series of easily identifiable target structures located around a second peripheral portion of said encoded data region; and

an orientation data structure located round a third peripheral portion of said encoded data region.

2. A data structure as claimed in claim 1 wherein said orientation data structure comprises a line of equal data points along an edge of said peripheral portion.

3. A data structure as claimed in claim 2 wherein said clock marks structures include a first line of equal data points in addition to a substantially adjacent second line of alternating data points locatec along an edge of said encoded data region.

4. A data structure as claimed in claim 3 wherein said clock mark structures are located on mutually opposite sides of said encoded data region.

5. A method of decoding a data structure encoded on the surface of an object, said data structure comprising:

a series of block data regions with each of said block data regions including;

an encoded data, region containing data to be decoded in an encoded form;

a series of clock marks structures located around a first peripheral portion of said encoded data region;

a series of easily identifiable target structures located around a second peripheral portion of said encoded data region;

the method comprising the steps of;

(a) scanning said data structure;

(b) locating the start of said data structure;

(c) locating said target structures including determining a current orientation of said target structures;

(d) locating said clock mark structures from the position of said target structures;

(e) utilizing said clock mark structures to determine an expected location of bit data of said encoded data region; and

(f) determining an expected data value for each of said bit data.

6. A method as claimed in claim 5 wherein said clock marks structures include a first line of equal data points in addition to a substantially adjacent second line of alternating data points located along an edge of said encoded data region and said utilising step (e) comprises running along said second line of alternating data points utilizing a pseudo phase locked loop type algorithm so as to maintain a current location within said clock mark structures.

7. A method as claimed in claim 6 wherein said determining step (f) comprises dividing a sensed bit value into three contiguous regions comprising a middle region and a first lower and a second upper extreme regions, and:

with those values within a first lower region, determining the corresponding bit value to be a first lower value;

with those values within a second upper region, determining the corresponding bit value to be a second upper value;

with those values in said middle regions, utilising the spatially surrounding values to determine whether said value is of a first lower value or a second upper value.

8. A method of determining an output data value of sensed data comprising:

(a) dividing a sensed data value into three contiguous regions comprising a middle region and a first lower and a second upper extreme regions, and;

with those values within a first lower region, determining the corresponding bit value to be a first lower value;

with those values within a second upper region, determining the corresponding bit value to be a second upper value; and

with those values in said middle regions, utilizing the spatially surrounding values to determine whether said value is of a first lower value or a second upper value.