Image processing system

An image processing system comprising a first image processing apparatus which records, on a recording medium, composite image information created by embedding invisible sub-information in visible main image information, and a second image processing apparatus which restores the sub-information from the composite image information recorded on the recording medium by the first image processing apparatus,

• the first image processing apparatus including
• a first pre-processing unit which performs, for main image information, first pre-processing corresponding to pixel formation processing for image recording in the first image processing apparatus,
• a second pre-processing unit which performs geometric transformation with respect to the main image information having undergone the first pre-processing by the first pre-processing unit,
• an embedding processing unit which creates composite image information by embedding sub-information in main image information in an invisible state using the main image information, the sub-information, and key information used to restore the sub-information,
• an inverse transformation unit which performs transformation processing inverse to the transformation processing by the second pre-processing unit with respect to the composite image information created by the embedding processing unit, and
• a recording unit which records the composite image information having undergone the inverse transformation processing by the inverse transformation unit by an alternate driving/recording scheme of alternately forming even-numbered and odd-numbered pixels in a main scanning direction of a recording device on a recording line basis, and
• the second image processing apparatus including
• an image input unit which inputs the composite image information from the recording medium on which the composite image information is recorded by the recording unit of the first image processing apparatus,
• a frequency component extracting unit which extracts a spatial frequency component unique to the key information from the composite image information input by the image input unit, and
• a reconstructing unit which reconstructs the sub-information from the spatial frequency component extracted by the frequency component extracting unit.

An image processing apparatus comprising:

• an image input unit which inputs composite image information from a recording medium on which the composite image information is recorded, which is created by color difference modulation processing using visible main image information, sub-information embedded in the main image information in an invisible state, and key information used to restore the sub-information;
• a frequency component extracting unit which extracts a spatial frequency component unique to the key information from the composite image information input by the image input unit;
• and
• a reconstructing unit which reconstructs the sub-information from the spatial frequency component extracted by the frequency component extracting unit.

An image processing apparatus comprising:

• an image input unit which inputs composite image information from a recording medium on which the composite image information is recorded, which is created by color difference modulation processing using visible main image information, sub-information embedded in the main image information in an invisible state, and key information used to restore the sub-information;
• a color component information storage unit which stores color component information;
• a color component extracting unit which extracts a color component from the composite image information input by the image input unit on the basis of the color component information stored in the color component information storage unit;
• a frequency component extracting unit which extracts a spatial frequency component unique to the key information from the color component extracted by the color component extracting unit;
• and
• a reconstructing unit which reconstructs the sub-information from the spatial frequency component extracted by the frequency component extracting unit.

An image processing apparatus comprising:

• an image input unit which inputs composite image information from a recording medium on which the composite image information is recorded, which is created by color difference modulation processing using visible main image information, sub-information embedded in the main image information in an invisible state, and key information used to restore the sub-information;
• an area extracting unit which extracts a local area from the composite image information input by the image input unit;
• a color feature extracting unit which extracts a color feature in the local area extracted by the area extracting unit from the local area;
• a color combining unit which creates color component composite image information by combining color components on the basis of the color feature extracted by the color feature extracting unit;
• a frequency component extracting unit which extracts a spatial frequency component unique to the key information from the color component composite image information created by the color combining unit;
• and
• a reconstructing unit which reconstructs the sub-information from the spatial frequency component extracted by the frequency component extracting unit.

An image processing apparatus comprising:

• an image input unit which inputs composite image information from a recording medium on which the composite image information is recorded, which is created by color difference modulation processing using visible main image information, sub-information embedded in the main image information in an invisible state, and key information used to restore the sub-information;
• an area extracting unit which extracts a local area from the composite image information input by the image input unit;
• a color feature extracting unit which extracts a color feature in the local area extracted by the area extracting unit from the local area;
• a reconstruction parameter determining unit which determines a reconstruction parameter on the basis of the color feature extracted by the color feature extracting unit;
• a frequency component extracting unit which extracts a spatial frequency component unique to the key information from the composite image information input by the image input unit;
• and
• a reconstructing unit which reconstructs the sub-information from the spatial frequency component extracted by the frequency component extracting unit by using the reconstruction parameter determined by the reconstruction parameter determining unit.

An image processing method comprising:

• inputting composite image information from a recording medium on which the composite image information is recorded, which is created by color difference modulation processing using visible main image information, sub-information embedded in the main image information in an invisible state, and key information used to restore the sub-information;
• extracting a spatial frequency component unique to the key information from the composite image information input from the recording medium;
• and
• reconstructing the sub-information from the spatial frequency component extracted by extracting the frequency component.

An image processing method comprising:

• inputting composite image information from a recording medium on which the composite image information is recorded, which is created by color difference modulation processing using visible main image information, sub-information embedded in the main image information in an invisible state, and key information used to restore the sub-information;
• extracting a color component from the composite image information input from the recording medium on the basis of the color component information stored in a color component information storage unit;
• extracting a spatial frequency component unique to the key information from the extracted color component;
• and
• reconstructing the sub-information from the extracted spatial frequency component.

An image processing method comprising:

• inputting composite image information from a recording medium on which the composite image information is recorded, which is created by color difference modulation processing using visible main image information, sub-information embedded in the main image information in an invisible state, and key information used to restore the sub-information;
• extracting a local area from the composite image information input from the recording medium;
• extracting a color feature in a local area extracted the composite image information from the local area;
• creating color component composite image information by combining color components on the basis of the color feature extracted from the local area;
• extracting a spatial frequency component unique to the key information from the created color component composite image information;
• and
• reconstructing the sub-information from the extracted spatial frequency component.

An image processing method comprising:

• inputting composite image information from a recording medium on which the composite image information is recorded, which is created by color difference modulation processing using visible main image information, sub-information embedded in the main image information in an invisible state, and key information used to restore the sub-information;
• extracting a local area from the composite image information input from the recording medium;
• extracting a color feature in the extracted local area from the local area;
• determining a reconstruction parameter on the basis of the color feature extracted from the local area;
• extracting a spatial frequency component unique to the key information from the composite image information input from the recording medium;
• and
• reconstructing the sub-information from the spatial frequency component extracted by extracting the frequency component by using the reconstruction parameter determined on the basis of the color feature.