1. An image processing device, comprising: an interest area detector that detects interest areas included in time-series images captured in time series; a calculation processing unit that calculates first feature amounts indicative of features of the interest areas; an area classification unit that classifies the interest areas into area groups, based on the first feature amounts of the interest areas and the position in time for each of the captured time-series images that includes the interest areas; an area selection unit that selects, based on second feature amounts of the interest areas in each of the area groups, one or more representative areas representing the interest areas belonging to each of the area groups, from among the interest areas belonging to each of the area groups; and a representative image output unit that outputs one or more representative images including the representative areas in the time-series images.