Disclosed is a threshold matrix generating method involving: a step for generating q(x, y, g) in which the number of dots in an initial dot pattern is varied; a step for calculating an error matrix (ERR(x, y, g)) of q(x, y, g); a step for calculating AVE(a, b) which represents the homogeneity of the number of dots in small sections into which the dot pattern has been divided; a step for determining the two pixels, of which the dot positions are to be switched, on the basis of ERR (x, y, g) and AVE(a, b); a step for switching the dot positions; a step for calculating the evaluation value (MSE(n)) of q(x, y, g) after the positional switch; a step for repeating the positional switch of the dots until a q(x, y, g) satisfying MSN(n)MSN(n-1) is obtained; and a step for repeating the generation of q(x, y, g) and the positional switch of the dots with q(x, y, g) functioning as the initial dot pattern.
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