1. An image processing device comprising: a feature point extraction unit that extracts feature points from a marker image included in an input image; a feature amount calculation unit that calculates feature amounts of the feature points; an image processing unit that processes the marker image to transform the feature amounts of non-distinguishing feature points into feature amounts of distinguishing feature points when the feature points extracted from the marker image are not distinguishing, so that a value of the feature amount of a feature point of interest which is a feature point in which interest is taken does not approximate values of the feature amounts of the feature points near the feature point of interest; and a marker image generation unit that generates a new marker image based on the processing result.