in which the extraction unit includes a person extraction unit that analyzes moving image data to be analyzed and extracts a person whose appearance frequency in the moving image data to be analyzed satisfies a predetermined condition among persons detected in the moving image data to be analyzed, and

the output unit outputs information regarding the extracted person.

3. The data processing apparatus described in 2,

in which the moving image data to be analyzed includes a plurality of pieces of child data captured at a plurality of places different from each other, and

the person extraction unit determines whether or not each person detected in the moving image data to be analyzed appears in each of the plurality of pieces of child data, and based on a result of the determination, calculates an appearance frequency for each person detected in the moving image data.

4. The data processing apparatus described in 2,

in which the moving image data to be analyzed includes moving image data captured at the same place over a predetermined time period, and

the person extraction unit analyzes the moving image data to be analyzed in units of time windows, each time window having a time width smaller than the predetermined time period, determines whether or not each person detected in the moving image data to be analyzed appears in each of a plurality of the time windows, and calculates an appearance frequency for each detected person based on a result of the determination.

5. The data processing apparatus described in 4, further including an input receiving unit that receives a user input to set a time width of the time window.