In the graph showing a temporal change in appearance frequency, the horizontal axis indicates time, and the vertical axis indicates appearance frequency (the number of appearances). The graph shows a temporal change in the number of appearances (0 to 24) per day with the time width of the time window being one hour. The scale interval on the horizontal axis in the graph may be set by the user. As described above, the temporal change of the time window may be set by the user.

As shown in FIG. 11, the output unit 20 may output information showing a face image of the person and the presence or absence of appearance in each of the plurality of time windows in association with each of the plurality of persons extracted by the person extraction unit 10. In the illustrated example, the time width of the time window is one day. When the time width of the time window is one hour, the presence or absence of appearance in each time window for each hour will be shown, such as “May 4th, 0-1 o'clock” and “May 4th, 1-2 o'clock”.

According to the present example embodiment described above, the same advantageous effect as in the first to third example embodiments can be achieved. In addition, according to the present example embodiment, extraction results can be provided to the user in various display forms.

For example, by outputting the face image of a person extracted by the person extraction unit 10, the user can recognize the face of a person having a high appearance frequency.