A three-dimensional (3D) measurement method includes steps of: detecting a facial orientation and a gaze direction of a user through a field of view detection unit; determining an interested field of view according to the facial orientation and the gaze direction, and configuring a first set of scanning parameters according to the interested field of view through an computation control unit; and performing a first structured-light scan on a first scanning region corresponding to the interested field of view based on the first set of scanning parameters, and selectively performing a second structured-light scan on a second scanning region which is outside the first scanning region based on a second set of scanning parameters through a scanning unit.
