Study on Visible Light Characteristics of Ground Target and Its Protection

In this paper, the visible light characteristic of ground target was studied. The result indicated that the visible light radiation of ground target mainly comes from the solar radiance the target reflected. There is close relationship between the solar irradiance which irradiates on ground target and the sun-earth distance, the sun zenith angle, the weather condition, the height above sea level. The contrast between target and its background is decided by their reflectivity. When the contrast transmits in the atmosphere, the weather condition is the main impact factor. The measures that can be used to protect ground targets on visible light waveband were also discussed.