An information processing device includes a range image acquisition unit that acquires at least two range images of an observation object, a color image acquisition unit that acquires color images of the observation object, which respectively correspond to the range images, a feature portion detection unit that detects feature portions from the acquired color images, a calibration unit that performs calibration processing that associates each pixel of the color image with each point of the range image, which corresponds to each pixel, and generates calibration information that indicates each point corresponding to each pixel, and an alignment processing unit that performs alignment of the range images so that the detected feature portions overlap with each other by using the detected feature portions and the calibration information.