Data processing apparatus and method of expanding dot arrangement patterns

A data processing method comprising the steps of:

• using a pattern table arranging binarizing patterns correspondingly to positions of a pixel, each of which is used for a binarization process in which an arrangement of a number of dots depending on a value of multi-valued image data corresponding to the pixel is determined;
• and
• selecting the binarizing pattern depending on the position of the pixel and on the value of multi-valued image data corresponding to the pixel for executing the binarization process,
• wherein the pattern table corresponding to one of the values to be taken by the multi-valued image data includes a plurality of types of binarizing patterns which determine different arrangements of dots from each other, and
• the arrangement of each of the plurality of types of binarizing patterns in the pattern table corresponding to the one value has a characteristic that the arrangement is aperiodic and that low frequency components are fewer than high frequency components, and
• wherein the characteristic that the low frequency components are fewer than the high frequency components means a characteristic that an integration value of low frequency components that exist in a lower side range than a middle of a spatial frequency range in which frequency components exist is smaller than an integration value of high frequency components that exist in a higher side range than the middle of a spatial frequency range.

A non-transitory computer readable medium containing a program that is read by an information processing apparatus to make the information processing apparatus function as a data processing apparatus that uses a pattern table arranging binarizing patterns correspondingly to positions of a pixel, each of which is used for a binarization process in which an arrangement of a number of dots depending on a value of multi-valued image data corresponding to the pixel is determined, to select the binarizing pattern depending on the position of the pixel and on the value of multi-valued image data corresponding to the pixel for executing the binarization process,

• wherein the pattern table corresponding to one of the values to be taken by the multi-valued image data includes a plurality of types of binarizing patterns which determine different arrangements of dots from each other, and
• the arrangement of each of the plurality of types of binarizing patterns in the pattern table corresponding to the one value has a characteristic that the arrangement is aperiodic and that low frequency components are fewer than high frequency components, and
• wherein the characteristic that the low frequency components are fewer than the high frequency components means a characteristic that an integration value of low frequency components that exist in a lower side range than a middle of a spatial frequency range in which frequency components exist is smaller than an integration value of high frequency components that exist in a higher side range than the middle of a spatial frequency range.