Face detection device, face detection system, and face detection method

A face detection device that detects a face from an image including a person, the device comprising:

• a processor;
• and
• a memory including instructions that, when executed by the processor, cause the processor to perform operations including:
• receiving captured images by a camera;
• detecting at least one face region in the captured images;
• collating a feature quantity of a face in a face region with information of a face which is previously registered;
• determining whether a vitality detection mode has been selected, the vitality detection mode configured to recognize a face of a person in a living state but not a face of an object in a non-living state;
• when the vitality detection mode is determined to have been selected:
• extracting vital information which includes an index indicating the living state of a face imaged in the at least one face region, based on image data regarding the detected at least one face region;
• determining whether or not the face in the at least one face region is in the living state, based on the vital information;
• and
• when the face in the at least one face region is determined to be in the living state, recognizing a face region corresponding to the face which is determined to be in the living state among the at least one face region, as a face region of a living body, and the collating being performed by using of a feature quantity of the face in the face region corresponding to the face which is determined to be in the living state.