The object of this invention is to provide an image processing device and image input device which creates strong features, or enhanced pattern which could be recognized when the image was read and which would prove difficult to eliminate through subsequent image processing. When the image is generated at the later step, these features would be easily recognized by the processing according to this invention because the image is equipped with the enhanced pattern which is easy to detect. In order to achieve this object, the image processing device according to this invention is equipped with a data synthesizing unit to synthesize the clear target pattern on the candidate target pattern which is not fully clear when the recognition unit has detected a pattern similar to the target pattern.