Method for Two-Channel Coding of a Message

• US 20080167881A1
• Filed: 02/03/2006
• Published: 07/10/2008
• Est. Priority Date: 02/03/2005
• Status: Abandoned Application

• Current Assignee: Pitney Bowes Incorporated (Böwe Systec AG)
• Original Assignee: Pitney Bowes Incorporated (Böwe Systec AG)
• Inventors: Haas, Bertrand
• Application Number:
  US11/885,232
• Publication Number:
  US 20080167881A1
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: G06T 1/0042 Fragile watermarking, e.g. so as to detect tampering
• CPC Class Codes: G06T 1/0071 using multiple or alternating watermarks
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• CPC Class Codes: H04L 1/007 Unequal error protection for format H04L1/0078; for codes per se H03M13/35
• CPC Class Codes: H04L 1/0083 Formatting with frames or packets; Protocol or part of protocol for error control
• CPC Class Codes: H04N 1/32128 attached to the image data, e.g. file header, transmitted message header, information on the same page or in the same computer file as the image for information embedded in the image H04N1/32144
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 2201/3239 using a plurality of different authentication information
• CPC Class Codes: H04N 2201/3269 of machine readable codes or marks, e.g. bar codes or glyphs
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes
• CPC Class Codes: H04N 2201/3283 Compression

Abstract

A method for encoding a message including the steps of performing two-channel encoding of the message into a robust string and a fragile string; transmitting the robust string through a fragile channel; and transmitting the fragile string though a robust channel (FIG. 6). Before the step of performing two-channel encoding of the message into a robust string and a fragile string the number of characters in the message may be reduced to reduce the size of the encode message. The two channel encoding step includes the steps of creating the robust string by encoding the message using the codeword dictionary; and creating the fragile string by encoding the message using a compression algorithm. The robust string may be transmitted by embedding the robust string in an image. The fragile string may be transmitted by embedding the fragile string in a 2-D bar code.

Claims

1. A method of encoding a message, the method comprising the steps of:

performing two-channel encoding of the message into a robust string and a fragile string;

transmitting the robust string through a fragile channel; and

transmitting the fragile string though a robust channel.

2. The method of claim 1 comprising the further step of:

reducing the number of characters in the message before the step of performing two-channel encoding of the message into a robust string and a fragile string.

3. The method of claim 2 wherein the reducing step comprises at least one of the steps of:

eliminating spaces in the message;

combining common adjacent pairs of letters as one coded character; and

formatting the message to lower case.

4. The method of claim 1 wherein the two-channel encoding step comprises the steps of:

creating the robust string by encoding the message using the codeword dictionary; and

creating the fragile string by encoding the message using a compression algorithm.

5. The method of claim 1 wherein the robust string is transmitted by embedding the robust string in an image.

6. The method of claim 1 wherein the fragile string is transmitted by embedding the fragile string in a 2-D bar code.

7. The method of claim 1 wherein the codeword dictionary comprises a unique code for at least each of the characters in the message.

8. The method of claim 6 wherein the unique codes are based on statistical usage of the characters in a predetermined number of messages.

9. A method of decoding a message encoded in an image and 2-D bar code printed on a document, the method comprising the steps of:

reading a fragile string from the 2-D bar code and reading a robust string from the image;

decoding the fragile string using a decompression algorithm; and

decoding the robust string using a codeword dictionary.

10. A method of decoding a message transmitted in a robust channel and a fragile channel on a document, the method comprising the steps of:

reading a fragile string from a robust channel and reading a robust string from the fragile channel;

decoding the fragile string using a decompression algorithm; and

decoding the robust string using a codeword dictionary.