Patent ID: 8532737

Claim:
Apparatus for automatically monitoring a subject's activity states, comprising: a video recorder for recording a time series of live images of a subject; and a computing device communicating with said video recorder that is programmed to: derive a time series of motion arrays wherein each element in each motion array corresponds to a location in a recorded live image at a given time, and indicates motion or absence of motion of the subject at the location at the given time; for each motion array in the time series and for each of a plurality of times T, calculate a metric of repetitive motion, designated as R(T), according to the equation, R ⁡ ( T ) = max ⁢ { M ⁡ ( t ) M ⁡ ( t ) + N ⁡ ( t ) : T - Δ ⁢ ⁢ 1 ≤ t ≤ T - Δ2 } wherein t is a time during a preceding time interval T−Δ1≦t≦T−Δ2 for which a motion array has been derived, wherein Δ1>Δ2, M(t) is the number of elements (x,y) at which an element (x,y) of the motion array at time T indicates motion and an element (x,y) of the motion array at time t also indicates motion, and N(t) is the number of elements (x,y) at which an element of the motion array at time T indicates motion and an element (x,y) of the motion array at time t indicates absence of motion; and automatically infer information about the activity states of the subject from the thus calculated metrics of repetitive motion.