We present a non-contact monitoring system to measure the quality of sleep using near-infrared video in this paper. We envision a smart home environment in which a processing module can be installed in the bedroom to record and monitor sleep in a noninvasive manner. We describe the procedure adopted to infer motion information and discuss the method for estimating wake/sleep status from the acquired video. Performance of the proposed system was evaluated through comparison with simultaneous recordings of actigraph and polysomnography (PSG) data.