Image processing apparatus, information processing system, image processing method, and non-transitory computer-executable medium

An image processing method for performing color matching of colors acquired in two different states and having an identical target gradation value, the two different states including a first state and a second state, the image processing method comprising:

• acquiring a first colorimetric value of a target color mixture from a chart printed out from an image forming apparatus, based on one or more first gradation values, in the first state, the first colorimetric value corresponding to each of the one or more first gradation values;
• acquiring a second colorimetric value of an adjacent color mixture, for a second gradation value adjacent to at least one first gradation value among the one or more first gradation values, from the chart printed out from the image forming apparatus in the first state and acquiring a second colorimetric value of an adjacent color mixture, for a second gradation value adjacent to a remaining first gradation value other than the at least one first gradation value among the one or more first gradation values, from a chart printed out from the image forming apparatus in the second state, the second state being a state that occurs chronologically after the first state;
• acquiring a third colorimetric value of a pre-correction color mixture from a chart printed out from the image forming apparatus, based on each of the one or more first gradation values, in the second state, the third colorimetric value corresponding to each of the one or more first gradation values;
• adding a difference between the first colorimetric value and the second colorimetric value corresponding to the first colorimetric value to the third colorimetric value corresponding to the first colorimetric value and calculating a predicted colorimetric value of the target color mixture;
• determining whether a color difference between the predicted colorimetric value and the first colorimetric value corresponding to the predicted colorimetric value is less than or equal to a first threshold;
• acquiring, as a correction value, the second gradation value corresponding to the second colorimetric value from which the predicted colorimetric value corresponding to the color difference is calculated, in response to the color difference being less than or equal to the first threshold;
• and
• correcting a corresponding one of the one or more first gradation values by using the correction value such that a colorimetric value of the pre-correction color mixture becomes equal to a colorimetric value of the target color mixture.

A non-transitory computer-executable medium storing a program storing instructions which, when executed by a processor, causes the computer to perform a method comprising:

• acquiring a first colorimetric value of a target color mixture from a chart printed out from an image forming apparatus, based on one or more first gradation values, in the first state, the first colorimetric value corresponding to each of the one or more first gradation values;
• acquiring a second colorimetric value of an adjacent color mixture, for a second gradation value adjacent to at least one first gradation value among the one or more first gradation values, from the chart printed out from the image forming apparatus in the first state and acquiring a second colorimetric value of an adjacent color mixture, for a second gradation value adjacent to a remaining first gradation value other than the at least one first gradation value among the one or more first gradation values, from a chart printed out from the image forming apparatus in the second state, the second state being a state that occurs chronologically after the first state;
• acquiring a third colorimetric value of a pre-correction color mixture from a chart printed out from the image forming apparatus, based on each of the one or more first gradation values, in the second state, the third colorimetric value corresponding to each of the one or more first gradation values;
• adding a difference between the first colorimetric value and the second colorimetric value corresponding to the first colorimetric value to the third colorimetric value corresponding to the first colorimetric value and calculating a predicted colorimetric value of the target color mixture;
• determining whether a color difference between the predicted colorimetric value and the first colorimetric value corresponding to the predicted colorimetric value is less than or equal to a first threshold;
• acquiring, as a correction value, the second gradation value corresponding to the second colorimetric value from which the predicted colorimetric value corresponding to the color difference is calculated, in response to the color difference being less than or equal to the first threshold;
• and
• correcting a corresponding one of the one or more first gradation values by using the correction value such that a colorimetric value of the pre-correction color mixture becomes equal to a colorimetric value of the target color mixture.