Patent ID: 7492483

Claim:
A method of generating a threshold matrix for converting a continuous-tone image into a dot pattern representing a binary image, the method comprising: determining a size of the threshold matrix; determining the number of pixels of a dot of a minimum size; determining a pattern frequency at a dot percentage of an intermediate tone; determining candidate positions for the dots of the minimum size in a dot pattern so that the pattern frequency is provided at the dot percentage; determining the number of new dots of the minimum size at a next dot percentage with respect to a present dot percentage for which a dot pattern has been determined; and determining placement positions of thresholds in the threshold matrix so that the dot pattern corresponding to the next dot percentage is obtained by conversion with the threshold matrix, the dot pattern made up of dots in which the number of pixels is adjusted, wherein the determining the placement positions of the thresholds comprises: determining candidate positions for placing the thresholds based on the candidate positions for the dots of the minimum size in a dot pattern at the next dot percentage and the number of new dots of the minimum size at the next dot percentage; and determining the placement positions of the thresholds by adjusting the number of pixels of each of the dots so that the dot pattern has the next dot percentage.