Improving passenger safety in cars using novel radar signal processing

Abstract

According to the group Kids and Cars, since 1990, nearly 1000 kids lost their lives because they were deliberately or unintentionally left in parked vehicles to potentially overheat or freeze. The development of technology able to prevent and address this serious, worldwide problem is crucial. In this paper, we deploy a radar-based sensor for in-vehicle presence-absence detection of a living body. We present a novel radar signal processing technique to identify the presence or absence of a living body in a vehicle using a mm-wave frequency-modulated continuous-wave (FMCW) radar. Our proposed method is based on reflections from breathing cycles creating correlated and consistent micro-Doppler effects over time. The performance of the system is evaluated with adults and two phantoms mimicking the breathing of children in various scenarios. The results show that we can clearly detect any tiny living body in vehicles with 100% accuracy without a need for any compute-intensive complex signal processing, making the system of extreme low-cost. The results demonstrate the high sensitivity and robustness of the mm-wave system in extensive studies over the course of multiple months.

AI-Powered In-Vehicle Passenger Monitoring Using Low-Cost mm-Wave Radar

“…Hence, the only remaining signals are the ones coming from the passengers. As shown in our previous work [26], the capability to discriminate stationary objects from humans is one superiority of radar sensors over mechanical sensors that detect weight, force, acceleration, or pressure.…”

“…Then, the stationary clutter removal algorithm is performed on each channel to remove all stationary targets. To do so, the average value of the signal is computed and subtracted from the aggregated signals; removing the average is equivalent to eliminating the stationary scatters [26].…”

“…The techniques are mostly based on the micro-Doppler effects of the breathing of one alive subject inside a car without considering the occupied seats and the number of passengers. In our previous work [26], we proposed a novel radar signal processing technique to identify the presence or absence of a living body in a vehicle using a frequency modulated continuous wave (FMCW) radar.…”

Single-Channel FMCW-Radar-Based Multi-Passenger Occupancy Detection Inside Vehicle

“…In addition, using a multiple-input and multiple-output frequency-modulated continuouswave (FMCW) radar, machine learning algorithms were integrated with DOA estimation to identify occupied seats [17]. In addition, a small child or infant was detected by consistent micro-Doppler effects on the breathing cycles [18]. Although these results were based on certain criteria for the performance evaluation, the criteria were neither rigorous nor clearly defined.…”

“…Although these results were based on certain criteria for the performance evaluation, the criteria were neither rigorous nor clearly defined. Multi-passenger occupancy detection has been studied using the multi-channel FMCW radar [17,18]. However, the multi-channel FMCW radar is difficult to implement and its size and cost is relatively unfavourable compared with the single-channel version.…”