Image processing device and information storage medium including motion vector information calculation

A non-transitory information storage medium storing a program that causes a computer to function as:

• a normal light image acquisition section that acquires a plurality of normal light images in time series as the normal light image, the normal light image being an image that includes information within a wavelength band of white light;
• a special light image acquisition section that acquires a plurality of special light images in time series as the special light image, the special light image being an image that includes information within a specific wavelength band;
• a normal light motion vector information calculation section that calculates normal light motion vector information based on a feature quantity included in the normal light image, the normal light motion vector information indicating a motion vector between a plurality of normal light images;
• a special light motion vector information calculation section;
• and
• a noise reduction section that reduces an amount of noise included in the special light image based on the normal light motion vector information calculated by the normal light motion vector information calculation section, wherein
• the normal light motion vector information calculation section calculating first normal light motion vector information based on a plurality of normal light images acquired before and after a kth (k is a natural number) special light image among the plurality of special light images in time series, and calculating second normal light motion vector information based on a plurality of normal light images acquired before and after a (k+1)th special light image among the plurality of special light images in time series;
• and
• the special light motion vector information calculation section calculating special light motion vector information between the kth special light image and the (k+1)th special light image based on the first normal light motion vector information and the second normal light motion vector information.