Research On Visual Environment Requirements And Intelligent Lighting System In Tunnel

With the development of the tunnel and the increase of the total mileage, the rate of accident is also increasing. Due to the particularity of the tunnel structure, there are some special visual effect at the entrance of the cave, such as black-hole effect and glare effect. The human eye can not adapt to the environment in such a short time because of the rapid change of brightness. So the traffic accidents are easy to happen at the entrance. For tunnel lighting problem, the departments at home and abroad have formulated the standards. But there is no explicit method to study the safety lighting from the human physiology point of view. This problem has been widely concerned by experts, and it has an important significance in the sustainable development of the tunnel construction.The key to solve the problem is to research the adaptive capacity of human eye. This paper built a simulation platform to study dark adaptation, which can overcome the limitation of the study in actual tunnel. The platform can record the adaptable change process of eyes with the reduction of the surround light luminance. The platform is composed by the LED integrated optical source which can change the luminous environment and CMOS image sensor module which can grab the pupil change image. 8 subjects have taken part in this research, and the platform record the changing of their pupil area in different illumination, as well as the changing time.The test result shows that the relation between the pupil area and illumination presents a power function, and the pupil adaptation time is within 12s to 15s. According to this result and the speed limits(40km/h)in tunnel, it can calculate that the minimum safe distance is approximately 133m. That is to say, the length of the tunnel lighting based on the adaptation time of pupil is at least 133m which can ensure traffic safety in tunnel. This paper uses the simulation platform to simulate tunnel light environment so that it can provide essential requirements based on human visual biological factors for tunnel lighting safety distance. Combining eyes’ adaptation time,vehicle speed, distance of tunnel illumination and illumination difference, it can ascertain the safe distance in the tunnel,it also can provide a safe, fuel-efficient tunnel light environment control scheme for improvement of tunnel lighting environment.