SYSTEM, POSITION DETECTING DEVICE, POSITION DETECTING METHOD, AND PROGRAM

A system includes an event-driven type vision sensor that outputs an event signal indicating a two-dimensional position which is located within a field of view of the vision sensor and at which a light intensity change has occurred in a space, and a time of day at which the light intensity change has occurred, a light source that emits light having directivity toward the space, and a position detecting device including an event signal receiving section that receives the event signal, and a position detecting section that detects a three-dimensional position of the light intensity change on the basis of an angle at which the light source has emitted the light at the time of day, the two-dimensional position, and a positional relation between the vision sensor and the light source.