1. An image processing apparatus comprising: a region-of-interest decision unit that obtains a distance image that is measured by a distance image sensor located above an object space and that includes information of a distance between the distance image sensor and an object vertically below the distance image sensor in the object space, obtains an image that is captured by an imaging apparatus from a non-vertical direction, identifies an interest space region in which the object is likely to be present based on the distance image, and identifies a region of interest in the captured image corresponding to the identified interest space region; and an image analysis unit that performs first image analysis on the identified region of interest and second image analysis on regions of the captured image other than the identified region of interest, the second image analysis being different from the first image analysis, wherein the image analysis unit performs the first or second image analysis by performing matching processing on the identified region of interest, and the image analysis unit changes a selection range of patterns used for the first or second image analysis by performing pattern recognition of the region of interest based on relative distance information between the imaging apparatus supplying the captured image and the interest space region identified based on the distance image.