Method of converting image data, image data conversion apparatus and program

A method of converting first image data into second image data by using a predetermined conversion element provided in a predetermined image data processing apparatus, said first image data having a plurality of first color components, said plurality of first color components including two spot colors, said second image data having a plurality of second color components, each of said plurality of second color components being a process color, said method comprising the steps of:

• a) acquiring a plurality of first color density values for said plurality of first color components from said first image data;
• b) reading conversion information from a predetermined storage element, said conversion information including a plurality of conversion factors for obtaining a pseudocolor density value for each of said two spot colors;
• and
• c) converting said first image data into said second image data,
• the conversion in said step c) being performed by calculating a plurality of second color density values for said plurality of second color components based on said plurality of first color density values and said plurality of conversion factors,
• wherein a second color density value for a given color component included among said plurality of second color density values is calculated by subtracting the product of two pseudocolor density values for said given color component from the sum of said two pseudocolor density values, said two pseudocolor density values being obtained in corresponding relation to said two spot colors, each of the color density values being defined that a maximum value is “1”, said two pseudocolor density values for said given color component being calculated by multiplying a first color density value for said given color component included among said plurality of first color density values by a conversion factor for said given color component included among said plurality of conversion factors.

An image data conversion apparatus for converting first image data into second image data, said first image data having a plurality of first color components, said plurality of first color components being a spot color and at least one process color, said second image data having a plurality of second color components, each of said plurality of second color components being a process color, said image data conversion apparatus comprising:

• an acquisition element for acquiring a plurality of first color density values for said plurality of first color components from said first image data;
• a storage element for storing conversion information including a plurality of conversion factors for obtaining a pseudocolor density value for said spot color;
• a reading element for reading said conversion information from said storage element;
• and
• a conversion element for converting said first image data into said second image data,
• the conversion by said conversion element being performed by calculating a plurality of second color density values for said plurality of second color components based on said plurality of first color density values and said plurality of conversion factors,
• wherein a second color density value Hi for a given color component i included among said plurality of second color density values is calculated by
• Hi=Pi+s·Gi−Pi·s·Gi
• where said given color component i is one of said plurality of second color components, Pi is a first color density value for said given color component i included among said plurality of first color density values, Gi is a conversion factor for said given color component i included among said plurality of conversion factors, s is a first color density value for said spot color included among said plurality of first color density values, and each of the color density values is defined that a maximum value is “1”.

An image data conversion apparatus for converting first image data into second image data, said first image data having a plurality of first color components, said plurality of first color components including two spot colors, said second image data having a plurality of second color components, each of said plurality of second color components being a process color, said image data conversion apparatus comprising:

• an acquisition element for acquiring a plurality of first color density values for said plurality of first color components from said first image data;
• a storage element for storing conversion information including a plurality of conversion factors for obtaining a pseudocolor density value for each of said two spot colors;
• a reading element for reading said conversion information from said storage element;
• and
• a conversion element for converting said first image data into said second image data,
• the conversion by said conversion element being performed by calculating a plurality of second color density values for said plurality of second color components based on said plurality of first color density values and said plurality of conversion factors,
• wherein a second color density value for a given color component included among said plurality of second color density values is calculated by subtracting the product of two pseudocolor density values for said given color component from the sum of said two pseudocolor density values, said two pseudocolor density values being obtained in corresponding relation to said two spot colors, each of the color density values being defined that a maximum value is “1”, said two pseudocolor density values for said given color component being calculated by multiplying a first color density value for said given color component included among said plurality of first color density values by a conversion factor for said given color component included among said plurality of conversion factors.

A program stored in a computer, said program being executed in said computer thereby to cause said computer to function as a conversion element for a data processing apparatus, said conversion element executing a method of converting first image data into second image data, said first image data having a plurality of first color components, said plurality of first color components being a spot color and at least one process color, said second image data having a plurality of second color components, each of said plurality of second color components being a process color, said method comprising the steps of:

• a) acquiring a plurality of first color density values for said plurality of first color components from said first image data;
• b) reading conversion information from a predetermined storage element, said conversion information including a plurality of conversion factors for obtaining a pseudocolor density value for said spot color;
• and
• c) converting said first image data into said second image data,
• the conversion in said step c) being performed by calculating a plurality of second color density values for said plurality of second color components based on said plurality of first color density values and said plurality of conversion factors,
• wherein a second color density value Hi for a given color component i included among said plurality of second color density values is calculated by
• Hi=Pi+s·Gi−Pi·s·Gi
• where said given color component i is one of said plurality of second color components, Pi is a first color density value for said given color component i included among said plurality of first color density values, Gi is a conversion factor for said given color component i included among said plurality of conversion factors, s is a first color density value for said spot color included among said plurality of first color density values, and each of the color density values is defined that a maximum value is “1”.

A program stored in a computer, said program being executed in said computer thereby to cause said computer to function as a conversion element for a data processing apparatus, said conversion element executing a method of converting first image data into second image data, said first image data having a plurality of first color components, said plurality of first color components including two spot colors, said second image data having a plurality of second color components, each of said plurality of second color components being a process color, said method comprising the steps of:

• a) acquiring a plurality of first color density values for said plurality of first color components from said first image data;
• b) reading conversion information from a predetermined storage element, said conversion information including a plurality of conversion factors for obtaining a pseudocolor density value for each of said two spot colors;
• and
• c) converting said first image data into said second image data,
• the conversion in said step c) being performed by calculating a plurality of second color density values for said plurality of second color components based on said plurality of first color density values and said plurality of conversion factors,
• wherein a second color density value for a given color component included among said plurality of second color density values is calculated by subtracting the product of two pseudocolor density values for said given color component from the sum of said two pseudocolor density values, said two pseudocolor density values being obtained in corresponding relation to said two spot colors, each of the color density values being defined that a maximum value is “1”, said two pseudocolor density values for said given color component being calculated by multiplying a first color density value for said given color component included among said plurality of first color density values by a conversion factor for said given color component included among said plurality of conversion factors.

A program stored in a computer, said program being executed in said computer thereby to cause said computer to function as a data conversion apparatus for converting first image data into second image data, said first image data having a plurality of first color components, said plurality of first color components being a spot color and at least one process color, said second image data having a plurality of second color components, each of said plurality of second color components being a process color, said data conversion apparatus comprising:

• an acquisition element for acquiring a plurality of first color density values for said plurality of first color components from said first image data;
• a storage element for storing conversion information including a plurality of conversion factors for obtaining a pseudocolor density value for said spot color;
• a reading element for reading said conversion information from said storage element;
• and
• a conversion element for converting said first image data into said second image data,
• the conversion by said conversion element being performed by calculating a plurality of second color density values for said plurality of second color components based on said plurality of first color density values and said plurality of conversion factors,
• wherein a second color density value Hi for a given color component i included among said plurality of second color density values is calculated by
• Hi=Pi+s·Gi−Pi·s·Gi
• where said given color component i is one of said plurality of second color components, Pi is a first color density value for said given color component i included among said plurality of first color density values, Gi is a conversion factor for said given color component i included among said plurality of conversion factors, s is a first color density value for said spot color included among said plurality of first color density values, and each of the color density values is defined that a maximum value is “1”.

A program stored in a computer, said program being executed in said computer thereby to cause said computer to function as a data conversion apparatus for converting first image data into second image data, said first image data having a plurality of first color components, said plurality of first color components including two spot colors, said second image data having a plurality of second color components, each of said plurality of second color components being a process color, said data conversion apparatus comprising:

• an acquisition element for acquiring a plurality of first color density values for said plurality of first color components from said first image data;
• a storage element for storing conversion information including a plurality of conversion factors for obtaining a pseudocolor density value for each of said two spot colors;
• a reading element for reading said conversion information from said storage element;
• and
• a conversion element for converting said first image data into said second image data,
• the conversion by said conversion element being performed by calculating a plurality of second color density values for said plurality of second color components based on said plurality of first color density values and said plurality of conversion factors,
• wherein a second color density value for a given color component included among said plurality of second color density values is calculated by subtracting the product of two pseudocolor density values for said given color component from the sum of said two pseudocolor density values, said two pseudocolor density values being obtained in corresponding relation to said two spot colors, each of the color density values being defined that a maximum value is “1”, said two pseudocolor density values for said given color component being calculated by multiplying a first color density value for said given color component included among said plurality of first color density values by a conversion factor for said given color component included among said plurality of conversion factors.