1. An image processing apparatus, comprising: a feature point calculation section for calculating feature points included in input image data; and a features calculation section for calculating features of the input image data in accordance with relative positions of the feature points calculated by the feature point calculation section, the feature point calculation section including: a line detection section for detecting, from the input image data, a line image extending in a first direction and a line image extending in a second direction that is different from the first direction; and an intersection calculation section for calculating, as a feature point, an intersection of the line image extending in the first direction and the line image extending in the second direction.