Sleep monitoring and sleep apnea event detection using a 3D camera

This non-invasive method detects the stages of sleep from the respiratory motion recorded with a 3D time-of-flight (TOF) camera. After the patient falls asleep, his/her muscles relax and the degree of relaxation is different in each sleep stage. The relaxation of abdominal muscles leads to slight variations in the movement of the abdomen in some regions. From 3D video recordings, the signal of respiratory movement is extracted from all visible regions. The characteristic features of different sleep stages are extracted, comparing the correlation (coefficients) between different signals. In a similar way, obstructive sleep apnea events are also detected.