PROBLEM TO BE SOLVED: To prevent the head of a visitor other than a patient to be erroneously detected as the head of the patient.SOLUTION: An image processing apparatus 10 acquires an image and searches for the head of a person in an area to be monitored in the image. If any head is detected, the apparatus determines whether the detected head is the head of a patient to be observed on the basis of the orientation of the face of the patient. If it is the patients head, the apparatus tracks it and determines rising or departure from a bed. If the orientation of the face cannot be determined and if any movement of the detected head is sensed, the apparatus tracks the head.
