No-touch measurements of vital signs in small conscious animals

Figures

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  Fig. 1. Two setups of NCS for vital signs of small conscious animals. The signal is collected by the harmonic reader with digital baseband processing by the field-programmable gate array (FPGA) and microcontroller (MCU). (A) The wireless NCS system is realized by the harmonic RFID system with passive harmonic sensing tags. (B) The wired NCS system replaces the wireless links between the reader and the harmonic tag by RF cables for reduced interference and convenient indoor laboratory deployment.

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  Fig. 2. The vital sign monitoring of a laboratory rat by synchronous NCS and ECG measurements. (A) Experimental setup with the anesthetized rat for ECG electrode placement. (B) Data recording (5 min) of NCS and ECG. The inset shows waveform details at a selected half-second duration. a.u., arbitrary units. (C) Heartbeat interval extracted from NCS and ECG showing very close match. (D) Representative respiration signals demodulated from the phase of the NCS signal around from the third to the fourth second. (The picture was taken by Xiaonan Hui, School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.)

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  Fig. 3. The vital sign monitoring of a conscious pet hamster. (A) Illustrations of the experimental setup when the hamster was in its sleeping quarter. (B) Heartbeat (blue) and respiration (green) signals demodulated from NCS. The inset shows the heartbeat waveform details around the ninth second. (C) Heartbeat interval extraction for about 30 s. (D) Experimental setup when the hamster was running in the exercise wheel during the measurements. The NCS tag antenna was placed at the back of the wheel outside the wire cage. (E) Demodulated NCS raw data (red) and data after bandpass filtering (green) for 20 s. (F) The spectrum of the NCS signal indicates the frequency components of the body motion and the heartbeat as well as its harmonics. (G) Reconstructed time-domain heartbeat waveform after the equalized comb filtering. The inset shows the waveform details when the hamster was under the intermittent rest with less motion interference. (The pictures were taken by Xiaonan Hui, School of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14853, USA.)

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  Fig. 4. The vital sign monitoring of small conscious animals with noninvasive NCS setups. (A) Wired NCS setup for the parakeet. (B) Heartbeat (blue) and respiration (green) signals demodulated from NCS. (C) Extracted heartbeat intervals for about 1.5 min. (D) NCS setup for the Russian tortoise similar to Fig. 3A, where the antennas are under the wood chip flooring. (E) Normalized raw amplitude of the NCS signal for 3 min, which represents both breaths and heartbeats due to the shell structure. The inset shows the waveform details of the overlapped signals. The pink shaded sections indicate the heartbeats, while the green shaded sections indicate the breaths. The strong breath signal will overwhelm the heartbeat signal during the overlap. (F) The online processed signals during the same period as (E) by continuous wavelet transform (CWT) show clear separation of heartbeats and breaths for accurate rate estimation. The inset shows the extracted waveform details, indicating every peak in heartbeats and breaths. (G) NCS setup similar to Fig. 3A for the betta fish. The Tx and Rx antennas are deployed in the water close to the fish. (H) Demodulated NCS phase signal caused by the pectoral fin…