Using acoustic camera technology on inspection of noisy vehicles in Taiwan

In recent years, noise complaints on motor vehicles had shown an increasing trend and became an environmental concern issue in Taiwan. Since 2021, innovative acoustic camera technology used to inspect high-noise vehicles exceeding "Vehicle Noise Control Standard" would be fined. There are 111 sets of acoustic camera equipment using in 21 counties and cities in Taiwan, and local government issued 4,099 fines to violating vehicle owners. This environmental policy has been supported by people living near major road with ninety percent satisfaction. Currently, acoustic camera technology with sound radar adopted by some cities in France to locate noisy vehicles accurately and issue fines automatically. Array sound camera technology has been used to inspect noisy vehicles in Netherlands and Germany. Taiwan is the first country in Asia to use acoustic camera technology conducting inspections and law enforcement against noisy vehicles. The sound camera technology system is mainly composed of high-speed camera equipment, sound level meter and license plate recognition system. Fixed systems are prior to set on specific road in hot spots of public complaint to inspect and outlaw noisy vehicles. After implementation of acoustic camera technology in these years, some challenges need to overcome. First, people doubt with accuracy and fairness of law enforcement equipment. Second, noise judgment of multi-source vehicle with law enforcement. To improve accuracy of law enforcement and multi-sound source vehicle noise judgment, technology of combining sound photography with array microphones is developing in Taiwan. In the future, we plan to conduct research on multi-source vehicle noise judgment technology to improve inspection efficiency and ensure a peaceful environment.