BINARIZING DEVICE AND COMPUTER READABLE MEDIUM

A binarizing device includes: a difference vector calculation unit that calculates a difference vector between an average color in a peripheral pixel region and a current color of a current pixel; a selection unit that selects one of the average color and the current color as a significant color; and an output unit that, in a case where predetermined conditions are satisfied, outputs one of binary values, and that, in a case where at least one of the predetermined conditions is not satisfied, outputs the other of the binary values, wherein the selection unit calculates a run length of each of the average color and the current color in a plurality of directions in the peripheral pixel region, and selects one of the average color and the current color, which has a shorter run length, as the significant color.