Correcting color plate data for mis-registration in a sub-scanning direction by performing a pixel transition at the transition point aligned in the main-scanning direction

A control method for controlling an image processing apparatus processing image data, the control method comprising:

• extracting a component color of a special-color object specified with a special color in the image data;
• setting, in a case where a plurality of component colors are included and a transition point of the component color is included in a region of the special-color object, the transition point located therein outside the region of the special-color object;
• correcting color-plate data of a plurality of color plates acquired from the image data, by performing pixel transition process of the color plate data in a sub-scanning direction at the transition point aligned in a main-scanning direction;
• and
• forming an image corresponding to the color-plate data corrected by the pixel transition process.

A non-transitory computer-readable storage medium storing a program which causes a computer to perform an image processing method, the image processing method comprising:

• extracting a component color of a special-color object specified with a special color in image data;
• setting, in a case where a plurality of component colors are included and a transition point of the component color is included in a region of the special-color object, the transition point located therein outside the region of the special-color object;
• correcting color-plate data of a plurality of color plates acquired from the image data, by performing pixel transition process of the color plate data in a sub-scanning direction at the transition point aligned in a main-scanning direction;
• and
• forming an image corresponding to the color-plate data corrected by the pixel transition process.

An image processing apparatus in which mis-registration in a sub-scanning direction of an image to be formed by a plurality of image forming units is corrected by performing in a sub-scanning direction image transition at a transition point lined up in a main-scanning direction, the image processing apparatus comprising:

• an extraction unit configured to extract a component color of a special-color object specified with a special color in the image;
• a setting unit configured to, in a case where a plurality of component colors are included and the transition point is included in a region of the special-color object in image data of the image corresponding to the component color, set the transition point located therein outside the region of the special-color object;
• and
• a correction unit configured to, for the image data of the image corresponding to each of the plurality of image forming units, perform pixel transition at the transition point.