There is provided an apparatus for monitoring a subject occupying an item of furniture. The apparatus comprises a projector for fixed attachment to a moveable part of an item of furniture, which changes its position and/or orientation relative to a surface in response to a movement of a subject occupying the item of furniture. The projector is arranged to project a pattern onto the surface. The apparatus further comprises at least one camera arranged to capture sequential images of the surface and a processing unit. The processing unit is arranged to: receive the images from the at least one camera detect the projected pattern in the received images detect a change to at least one feature of the projected pattern in the received images determine whether the detected change satisfies at least one predefined criterion for a subject exit event and output a signal based on the determining.
