A split image generation portion generates split images. A split projected waveform generation portion generates split projected waveforms from the split images respectively. A projected waveform synthesizer portion generates projected waveforms by combining the split projected waveforms. A feature volume extraction portion extracts feature volumes from the generated projected waveforms. A feature volume correlation portion correlates feature volume data of a target image with feature volume data of a reference image. A correction value calculation portion calculates correction values in accordance with geometrical distortion between the reference image and the target image on the basis of a result of the correlation and generates an n-dimensional lookup table. An image collation portion collates the target image with the reference image in consideration of the geometrical distortion by using the lookup table.
