Image data processing apparatus and image data processing method

An image-data processing apparatus. The image-data processing apparatus includes: an imaging section capturing an image of a subject and generating image data; a feature-extraction processing section extracting a visual feature from the generated image data; a feature-comparison processing section comparing a visual feature, having been extracted from recorded image data in a recording medium and related to the recorded image data, with the visual feature extracted by the feature-extraction processing section; and a control section reading image data having the visual feature extracted by the feature-extraction processing section from the recording medium on the basis of the comparison result.