Image processing apparatus for gamma conversion of image data

An image processing method comprising:

• receiving multi-level image data;
• first converting including converting the multi-level image data into integer image data by referring to a first conversion table, the first conversion table containing data for converting the multi-level image data into the integer image data by discarding decimal parts of the multi-level image data subjected to gamma correction;
• generating matrix data for performing area coverage modulation by referring to the multi-level image data;
• second converting including converting the multi-level image data into decimal image data by referring to a second conversion table, the second conversion table containing data for converting the multi-level image data into the decimal image data by multiplying decimal parts of the multi-level image data subjected to gamma correction by the matrix data generated in the threshold setting unit;
• reducing levels of the decimal image data by using a threshold generated at the generating;
• adding the integer image data to the level-reduced decimal image data and outputting a result of addition as gamma conversion image data;
• and
• performing image processing on the gamma conversion image data.

A computer program product that includes a computer program stored on a non-transitory computer-readable recording medium, the computer program when read and executed on a computer causes the computer to execute:

• receiving multi-level image data;
• first converting including converting the multi-level image data into integer image data by referring to a first conversion table, the first conversion table containing data for converting the multi-level image data into the integer image data by discarding decimal parts of the multi-level image data subjected to gamma correction;
• generating matrix data for performing area coverage modulation by referring to on the multi-level image data;
• second converting including converting the multi-level image data into decimal image data by referring to a second conversion table, the second conversion table containing data for converting the multi-level image data into the decimal image data by multiplying decimal parts of the multi-level image data subjected to gamma correction by the matrix data generated in the threshold setting unit;
• reducing levels of the decimal image data by using a threshold generated at the generating;
• adding the integer image data to the level-reduced decimal image data and outputting a result of addition as gamma conversion image data;
• and
• performing image processing on the gamma conversion image data.