Apparatus and method for watermark data insertion and apparatus and method for watermark data detection

• US 6,240,121 B1
• Filed: 07/09/1998
• Issued: 05/29/2001
• Est. Priority Date: 07/09/1997
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Senoh, Takanori
• Primary Examiner(s): Tse, Young T.
• Application Number:
  US09/112,388
• Time in Patent Office: 1,055 Days
• Field of Search: 375/130, 375/140, 375/142, 375/147, 375/150, 380/4, 380/5, 382/248, 382/250
• US Class Current: 375/130
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 2201/0052 Embedding of the watermark in the frequency domain
• CPC Class Codes: G06T 2201/0083 whereby only watermarked image required at decoder, e.g. source-based, blind, oblivious
• CPC Class Codes: H04N 1/32154 Transform domain methods H04N1/32309 takes precedence
• CPC Class Codes: H04N 1/3216 using Fourier transforms
• CPC Class Codes: H04N 1/32165 using cosine transforms
• CPC Class Codes: H04N 1/3217 using wavelet transforms
• CPC Class Codes: H04N 1/32176 using Walsh, Hadamard or Walsh-Hadamard transforms
• CPC Class Codes: H04N 1/32181 using Karhunen-Loeve transforms
• CPC Class Codes: H04N 1/32187 with selective or adaptive application of the additional information, e.g. in selected frequency coefficients
• CPC Class Codes: H04N 21/23892 involving embedding information at multiplex stream level, e.g. embedding a watermark at packet level
• CPC Class Codes: H04N 21/8358 involving watermark protecting executable software by watermarking G06F21/16; image watermarking in general G06T1/0021; watermarks inserted in still images for transmission purposes H04N1/32144; inserting watermarks during video coding H04N19/467

Abstract

A watermark data insertion method for inserting watermark data into an input original signal is provided. The method includes: a frequency transform step for applying a frequency transform to the original signal to form an intermediate signal; a watermark data insertion step for inserting the watermark data into a first set of frequency component of the intermediate signal; and a frequency inverse transform step for applying an inverse frequency transform to the intermediate signal, the watermark data having been inserted into the intermediate signal, thereby obtaining a signal containing the watermark data embedded therein. The watermark data insertion step includes: determining, based on pseudo random numbers, the first set of frequency components of the intermediate signal into which the watermark data is inserted; and using a second set of frequency components of the intermediate signal as a reference signal, the watermark data not being inserted into the second set of frequency components.

Claims

1. A watermark data insertion method for inserting watermark data into an input original signal, comprising:

a frequency transform step of applying a frequency transform to the original signal to form an intermediate signal;

a watermark data insertion step of inserting the watermark data into a first set of frequency components of the intermediate signal; and

a frequency inverse transform step of applying an inverse frequency transform to the intermediate signal, the watermark data having been inserted into the intermediate signal, thereby obtaining a signal containing the watermark data embedded therein,

wherein the watermark data insertion step comprises;

determining, based on pseudo random numbers, the first set of frequency components of the intermediate signal into which the watermark data is inserted; and

using a second set of frequency components of the intermediate signal as a reference signal, the watermark data not being inserted into the second set of frequency components.

2. A watermark data insertion method according to claim 1, wherein the frequency transform applied in the frequency transform step is a wavelet transform, and the inverse frequency transform applied in the frequency inverse transform step is an inverse wavelet transform.

3. A watermark data insertion method according to claim 1, wherein the watermark data insertion step comprises:

a weighting step of increasing or decreasing a signal amplitude of the watermark data in accordance with an amplitude of the first set of frequency components of the intermediate signal into which the watermark data is inserted.

4. A watermark data insertion method according to claim 1, wherein the watermark data insertion step comprises determining the first set of frequency components of the intermediate signal into which the watermark data is inserted by using pseudo random numbers having frequency-dependent weights.

5. A watermark data insertion method according to claim 1, wherein the watermark data insertion step comprises:

a weighting step of increasing or decreasing a signal amplitude of the watermark data in accordance with a frequency of the first set of frequency components of the intermediate signal into which the watermark data is inserted.

6. A watermark data insertion method according to claim 1, wherein the watermark data insertion step comprises converting binary data representing the watermark data into predetermined positive and negative values, and thereafter inserting the converted binary data into the first set of frequency components of the intermediate signal.

7. A watermark data insertion apparatus for inserting watermark data into an input original signal, comprising:

a frequency transform section for applying a frequency transform to the original signal to form an intermediate signal;

a watermark data insertion section for inserting the watermark data into a first set of frequency components of the intermediate signal; and

a frequency inverse transform section for applying an inverse frequency transform to the intermediate signal, the watermark data having been inserted into the intermediate signal, thereby obtaining a signal containing the watermark data embedded therein,

wherein the watermark data insertion section determines the first set of frequency components of the intermediate signal into which the watermark data is inserted based on pseudo random numbers, and uses a second set of frequency components of the intermediate signal as a reference signal, the watermark data not being inserted into the second set of frequency components.