Method and apparatus for embedding and reproducing watermark into and from contents data

1. An apparatus for embedding a watermark into original picture data, comprising:

pattern generating means for generating a fixed two-dimensional bit pattern which remains unchanged when being rotated through one of 90, 180, and 270 degrees;

embedding-position deciding means for deciding a two-dimensional watermark-embedding region with respect to the original picture data;

random-number generating means for generating random-number data representing a random number;

data-storing and calculating means for storing pattern data representing a specified two-dimensional bit pattern which remains unchanged when being rotated through one of 90, 180, and 270 degrees, and for performing given logical operation between the fixed two-dimensional bit pattern and the specified two-dimensional bit pattern to calculate a desired two-dimensional bit pattern for specified bits, the specified bits being among bits in a first portion of the original picture data which corresponds to a first part of the two-dimensional watermark-embedding region;

operation means for executing the given logical operation between watermark data and the random-number data; and

mixing means for changing the specified bits to represent the desired two-dimensional bit pattern, and for embedding a result of the given logical operation executed by the operation means in a second portion of the original picture data which corresponds to a second part of the two-dimensional watermark-embedding region different from the first part thereof;

wherein the fixed two-dimensional bit pattern has a square matrix array of bits with a same number of vertical-line bits and horizontal-line bits, and the specified two-dimensional bit pattern has a square matrix array of bits and is equal in size to the fixed two-dimensional bit pattern, the fixed two-dimensional bit pattern being a first “0” and “1” checkered bit pattern, the specified two-dimensional bit pattern being a second “0” and “1” checkered bit pattern different from the first “0” and “1” checkered bit pattern.

2. A method of embedding a watermark into original picture data, comprising the steps of:

generating a fixed two-dimensional bit pattern which remains unchanged when being rotated through one of 90, 180, and 270 degrees;

deciding a two-dimensional watermark-embedding region with respect to the original picture data;

generating random-number data representing a random number;

storing pattern data representing a specified two-dimensional bit pattern which remains unchanged when being rotated through one of 90, 180, and 270 degrees;

performing given logical operation between the fixed two-dimensional bit pattern and the specified two-dimensional bit pattern to calculate a desired two-dimensional bit pattern for specified bits, the specified bits being among bits in a first portion of the original picture data which corresponds to a first part of the two-dimensional watermark-embedding region;

executing the given logical operation between watermark data and the random-number data; and

changing the specified bits to represent the desired two-dimensional bit pattern, and embedding a result of the executed given logical operation in a second portion of the original picture data which corresponds to a second part of the two-dimensional watermark-embedding region different from the first part thereof;

wherein the fixed two-dimensional bit pattern has a square matrix array of bits with a same number of vertical-line bits and horizontal-line bits, and the specified two-dimensional bit pattern has a square matrix array of bits and is equal in size to the fixed two-dimensional bit pattern, the fixed two-dimensional bit pattern being a first “0” and “1” checkered bit pattern, the specified two-dimensional bit pattern being a second “0” and “1” checkered bit pattern different from the first “0” and “1” checkered bit pattern.

3. An apparatus for embedding a watermark into original picture data, comprising:

map data storing means for storing map data indicating a watermark embedded position, where the watermark should be embedded, with respect to a frame represented by the original picture data;

pattern generating means for generating bits representing a predetermined bit pattern in response to the map data, the predetermined bit pattern corresponding to the watermark and being in a position coincident with the watermark embedded position indicated by the map data, the predetermined bit pattern being a first two-dimensional bit pattern having a square matrix array of bits with a same number of vertical-line bits and horizontal-line bits, the predetermined bit pattern remaining unchanged when being rotated through one of 90, 180, and 270 degrees;

specified-bit detecting means for detecting bits in the original picture data as specified bits into which the watermark can be embedded;

data-storing and calculating means for storing pattern data representing a specified bit pattern being a second two-dimensional bit pattern having a square matrix array of bits and equal in size to the first two-dimensional bit pattern, the specified bit pattern remaining unchanged when being rotated through one of 90, 180, and 270 degrees, the data-storing and calculating means being further for performing given logical operation between the predetermined bit pattern and the specified bit pattern to calculate a desired bit pattern for the specified bits, wherein the desired bit pattern can be converted into the specified bit pattern by the given logical operation with the predetermined bit pattern in a decoder side; and

mixing means for changing the specified bits to represent the desired bit pattern to convert the original picture data into watermark-embedded picture data.

4. An apparatus as recited in claim 3 , wherein the first two-dimensional bit pattern is a first “0” and “1” checkered bit pattern, and the second two-dimensional bit pattern is a second “0” and “1” checkered bit pattern different from the first “0” and “1” checkered bit pattern.

5. An apparatus as recited in claim 4 , wherein the desired bit pattern is formed by bits of “1” only.

6. A method of embedding a watermark into original picture data, comprising the steps of:

generating map data indicating a watermark embedded position, where the watermark should be embedded, with respect to a frame represented by the original picture data;

generating bits representing a predetermined bit pattern in response to the map data, the predetermined bit pattern corresponding to the watermark and being in a position coincident with the watermark embedded position indicated by the map data, the predetermined bit pattern being a first two-dimensional bit pattern having a square matrix array of bits with a same number of vertical-line bits and horizontal-line bits, the predetermined bit pattern remaining unchanged when being rotated through one of 90, 180, and 270 degrees;

detecting bits in the original picture data as specified bits into which the watermark can be embedded;

generating pattern data representing a specified bit pattern being a second two-dimensional bit pattern having a square matrix array of bits and equal in size to the first two-dimensional bit pattern, the specified bit pattern remaining unchanged when being rotated through one of 90, 180, and 270 degrees;

performing given logical operation between the predetermined bit pattern and the specified bit pattern to calculate a desired bit pattern for the specified bits, wherein the desired bit pattern can be converted into the specified bit pattern by the given logical operation with the predetermined bit pattern in a decoder side; and

changing the specified bits to represent the desired bit pattern to convert the original picture data into watermark-embedded picture data.

7. A method as recited in claim 6 , wherein the first two-dimensional bit pattern is a first “0” and “1” checkered bit pattern, and the second two-dimensional bit pattern is a second “0” and “1” checkered bit pattern different from the first “0” and “1” checkered bit pattern.

8. A method as recited in claim 7 , wherein the desired bit pattern is formed by bits of “1” only.