Multiparameter Sleep Monitoring Using a Depth Camera - Biomedical Engineering Systems and Technologies - page 291

find the exact peak points and valley points. Fig. 3 shows a fragment of the breathing
signal (blue line) and the measurement results (vertical gray line) during a realistic
overnight sleep. While the turning points of the breathing signals are detected, the
information of the breathing conditions can be figured out easily. The breathing con-
ditions include the breathing rate, breathing depth, breathing stability, inhalation time,
exhalation time, inhalation/exhalation ratio, and sleep apnea symptoms.

Fig. 2. Depth image Processing Procedure of our system. (a) Captured color image. (b) Cap-
tured depth image. (c) View transformed image. (d) Filtered image. (e) Cross-section image. (f)
Final result of head/torso detection.

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Fig. 3. Breath Measurement. The blue line indicates the raw breathing signals, and the gray
lines indicate the turning points which we detected.