Experimental Study On Visual Visibility And Penetration Of Electric Light Source In The Medium In The Mesopic Vision

Based on experiments, three main effect factors of visual visibility level which are brightness, contrast and medium density, as well as visibility and penetration are studied in different electric light sources and different medium density in this paper. According to the research trends, primary work and conclusions of the paper are listed as follows:In gaseous medium mesoptic visual condition, target objects and background are divided into 12 different gray levels of positive and negative contrast types with RGB gray level color system. Furthermore, the experiment about brightness contrast and eyesight is performed in different background brightness and the relations between positive, negative contrast types and visual visibility are measured in the situation of equal brightness difference. At last it draws variation of background brightness and visual visibility in the contrast of different gray target objects and backgrounds. Especially, the visual level of positive contrast is lower than that of negative level.Based on tests, the empty visual chat is chosen as the target while the opaque black cardboard as the background under the misty (liquid medium) condition. The relation of mist thickness and visual visibility in different visual environment, transmission rate of different light sources and color LED, as well as the relation between transmission rate and distance, are then studied. It turns out that the visual visibility decreases as the fog thickness increases, in no matter what the visual environment. In other words, the higher the fog thickness, the lower the visual visibility. Specially, the visibility is down to zero when the fog thickness ishigher than 90%. The transmittance of filmed glass is replaced by the illumination transmission rate through analyzing relationship of them. Then the transmittance of film and the glass attached film are detailed measured in different light source (high pressure sodium lamp, metal halide lamp, LED, fluorescent lamp, electric incandescent lamp) in the mesopic vision. It turns out that, in case of glass labeled film, the transmittance of driving visual areas is further lower than the national mandatory standards prescribed GB7258-1997 numerical (this value is only suitable for sun). Besides, transmittance of these film glass are Approximate the same in different artificial light sources,The experiment methods of this paper are different from others', and the main academic innovations are listed as follow: A new research method ("E"visual chat measurement and OCR software identification) is constructed. It uses human eyes (subjective) and software (objective) to evaluate and test the experiments, so as to ensure the objective and rationality of the experiment.A new method about how to evaluate fog thickness (using the reverse numerical of the illumination transmission rate to define percentage thickness of fog) is established. It turns out, to some extent, methods and conclusions of the experiment reflect changing rules and visibility of water vapor environment, which have some guiding significance for choice of road lighting equipment, lighting standards and improvement of road traffic safety in severe weather conditions.