Patent ID: 7414756
Filing Date: 2008-08-19
Classification: H04N

Abstract:
1. An image processing apparatus that converts image data represented by tone values for pixels constituting an image into dot data representing dot on/off state for each of pixels, the image processing apparatus comprising: a dot data converting module that, forming units by grouping adjacent pixels in a predetermined number, converts the image data included in each of units into the dot data; and a dot data storage module that stores the dot data in a condition enabling identification of the dot on/off state for at least one of pixels within the converted units, wherein the dot data converting module comprises: a converted unit selecting module that calculates a sum of tone values for pixels grouped into the unit, and according to a correspondence relationship with the sum of tone values, selects a predetermined number of units from among the converted units; a pixel specifying module that, within a unit to be converted to the dot data, serially specifies a interested pixel for determination of dot on/off state; a dot data input module that inputs dot data of a pixel that is located in the predetermined number of units selected by the converted units selecting module and exists in a location having a predetermined relationship with the location of the interested pixel in the unit; and a dot formation determining module that, on the basis of tone value of image data for the interested pixel and the inputted dot data, determines the dot on/off state for the interested pixel, according to a characteristic that more readily determines a dot-on state the greater the tone value of the interested pixel; and wherein the converted unit selecting module executes the selection according to the correspondence relationship that, with respect to the sum of tone values smaller than a first predetermined value, a unit further away from the unit including the interested pixel is included in the predetermined number of units, than for the sum of tone values greater than the first predetermined value and smaller than a second predetermined value.