Image processing apparatus, image processing method and program

A non-transitory storage medium storing a computer program which on execution by a computer causes the computer to function as an image processing apparatus which converts an input image into a halftone image using a threshold value matrix including a plurality of threshold values, the image processing unit comprising:

• one or more circuits configured to cause the image processing apparatus to function as:
• a target value obtaining unit configured to obtain a target value relating to a target tone for a predetermined region based on pixel values of respective pixels included in the predetermined region and the threshold values corresponding to the respective pixels of the threshold value matrix;
• an evaluation value determination unit configured to determine evaluation values for respective pixels included in the predetermined region;
• and
• an output value determination unit configured to determine an output value of at least one pixel included in the predetermined region in the halftone image according to the target value and the evaluation values for the predetermined region.

An image processing method for performing an image process which converts an input image into a halftone image using a threshold value matrix including a plurality of threshold values, the method comprising:

• obtaining a target value relating to a target tone for a predetermined region based on pixel values of respective pixels included in the predetermined region and the threshold values corresponding to the respective pixels of the threshold value matrix;
• determining evaluation values for respective pixels included in the predetermined region;
• and
• determining an output value of at least one pixel included in the predetermined region in the halftone image according to the target value and the evaluation values for the predetermined.

An image processing apparatus which converts an input image into a halftone image using a threshold value matrix including a plurality of threshold values, the image processing apparatus comprising:

• one or more processors and at least one memory,
• the at least one memory being coupled to the one or more processors and having stored thereon instructions executable by the one or more processors,
• wherein the execution of the instructions causes the image processing apparatus to function as:
• a target value obtaining unit configured to obtain a target value relating to a target tone for a predetermined region, based on pixel values of respective pixels included in the predetermined region and the threshold values corresponding to the respective pixels of the threshold value matrix;
• an evaluation value determination unit configured to determine evaluation values for respective pixels included in the predetermined region;
• and
• an output value determination unit configured to determine an output value of at least one pixel included in the predetermined region in the halftone image according to the target value and the evaluation values for the predetermined region.