Study On Perceived Contrast Method Of Tunnel Lighting

Firstly, this thesis take perceived contrast design method as the research object, systematically analyzes the standards of tunnel lighting design in our country. The current k value, which is the focus of controversy in the two major international school, and the difference is more than 5 times. With the in-depth study of the tunnel lighting, CIE recommended the perceived contrast design method in 2004, this method considers the human eyes adaptation effects in the air by light scattering intensity and car windshields impact, and other factors to driver of obstacles on the road. Obviously, the contrast detection method to calculate the brightness of the tunnel entrance lighting design will be more scientific, more conducive to energy saving and more safety of tunnel lighting.In the second part of the thesis, the influence of the perceived contrast method on the atmospheric brightness is studied. Through the study of atmospheric radiative transfer equation, the air column brightness between the observer and the target is affected by distance, visibility, the brightness of the environment and other effects. The paper put forward a method by measuring the differential luminance of observer position's luminance and target's apparent brightness to calculate air column brightness.By measuring visibility distance in box filled with smoke, different target brightness and different distances, after analysis of the measurement data, the relationship of air column brightness, distance, brightness and visibility distance is obtained.In the outdoor actual measurement, target's level illumination, incident illumination, visibility and different distance is measured. And the atmospheric column brightness is proposed for the calculation of the perceived contrast of tunnel illumination.In the third part of the thesis, the perceived contrast design method is applicated in four tunnels of Yongwu Expressway, and makes a comparative with various design methods for the same Huangshanling tunnel. it can be seen that the entrance brightness calculated by contrast detection method is less than k method, and lower than environment diagram method, and also lower than the digital camera method. The SRN evaluation method's influence by subjective effects is too large, so the results are not accurate enough. Relative to equivalent veiling luminance method, the contrast detection method considering the many factors that affect the driver's vision, so it is more scientific.The fourth chapter proposed the dynamic evaluation method by use eye tracking system, it take small target decected distance as the standard, to estimate the tunnel lighting effect.Recording of the driver's visual tracking information with an eye tracker, according to a series of operational behavior and driving intention, a Hidden Markoff Model(HMM) is established. Through the sensor and eye tracking data, we can determine whether the driver do detect the small target.This paper focuses on the analysis of the driver's dynamic visual model, and studies the view range, fixation time and duration time. According to the driver's detection time, travel time and speed, the driver's detection distance can be obtained under the illumination condition. If the distance is greater than the safe stopping distance, it is indicated that the lighting condition is qualified.Small target detection distance directly reflects the quality of tunnel lighting, it is a comprehensive index of safety and energy saving. Through the actual measurement of Fujian Expressway four tunnels, the study shows that this method is feasible. And the dynamic measurement method contains lighting system and external environment on physiology and psychology of human visual effect. Therefore, this is more scientific, more reasonable evaluation method than the traditional methods.The innovations of the paper are as follows:(1) Innovation on theories: The paper study on the atmospheric radiation transmission equation, find air column brightness between observer and the target affected by distance, visibility, brightness of the environment and other aspects. And the paper put forward a method to calculate air column brightness with two luminance difference.(2) Innovation on method: For the first time, the paper proposes a method of dynamic evaluation of tunnel lighting based on the small target detection distance. The feasibility of the perceived contrst method for tunnel lighting design and the dynamic evaluation method based on the detection of small targets is verified by the experimental results in Fujian.(3) Innovation on application: China's current tunnel design based on the k method, for the first time, the perceived contrast design method is applicated in four tunnels of Yongwu Expressway. Comparative with other design methods, it is proved that the perceived contrast design method is more energy efficient, more scientific and more reasonable than other methods.