Figure 3
From: Noncontact assessment for fatigue based on heart rate variability using IR-UWB radar
Detecting system and data flow for heartrate measurement using IR-UWB radar sensor. (A) IR-UWB radar detecting system (front and back). In the front side, TX/RX Antenna, RAM memory and Microcontroller unit (MCU) are embedded; while in the back side radar chip are embedded in the detecting system. (B) Data stream from the IR-UWB radar sensor. (a) A raw radar signal was extracted after locating the target in the range with respect to time. (b) The raw signal, comprises of both respiratory and heartbeat signal. (b) A moving target indication (MTI) filter was used to remove clutter and background noise from the captured raw data. (c) A vital signs signal was acquired in the target range along the slow time axis by rasping the data. (d) The extracted vital signals were sent to the respective filters and processed using the fast Fourier transformation (FFT) to produce RR and HR. Finally, an accurate HR signal was obtained for further measuring HRV indexes.
