Research Of Several Key Technologies For Atmospheric Visibility Measurement

Visibility is a very important meteorological element for traffic, military, environment, and climate change. The method of measuring visibility using digital photographs has been applied and popularized because of it closing to the observation mode of human eye, convenient operation and reliable monitoring results. For the principle and shortage of the existing monitoring methods, the thesis studied some issues of the digital photographs visibility monitoring.The main contents of this thesis are included as below:1. The paper studies the daytime visibility algorithm and analysis on the principle of the dual differential luminance method for measuring daytime visibility. In order to overcome the dual differential luminance method that needs to maintain the standard viewing conditions, this paper proposes to calculate the daytime visibility method based on transmittance estimation and visual distance calculation. Experiment shows that good results achieved.2.This paper discusses the design and identification for the light source of nighttime visibility:The dual light source method for measuring the visibility at night, and the light source placed next to the blackbody to eliminate the environment light; Using LED as light source, the single light will be send evenly divided into two, this design effectively eliminates the power and light source fluctuations cause for observing the night visibility; This paper uses the method based on spatial information and potential target matching to identify the light source. Through the experiment, this paper’s design verify the double light source method measuring night visibility’s feasibility3. To build a system to measure, respectively, daytime and nighttime visibility, and standard data were compared to verify the feasibility of the algorithm.