Laser spot detection and characteristic analysis in space optical communication

In the space laser communication, the link of communication is builded in atmospheric random channel. the laser transmission is affected by the atmospheric turbulence seriously. The communication laser is modulated to circular polarized light in order to reduce the influence of the atmospheric turbulence. A several experiments are designed to validate that the circular polarized laser is available to reduce the communication noise in the space optical communication. The methods of the laser spot detection and spot parameter analysis is put forward in this paper: Firstly the subtraction of the background is used in image preprocessing in order to eliminate the influence of static background, then a series of methods such as the local dynamic threshold segmentation, edge extraction are used to detect and recognize the spot. Finally the parameters of the spot are calculated such as spot's average brightness, background's average brightness and the contrast gradient, and the characteristic of the laser communication is analyzed. The experiment results show that the circular polarized laser can enhance the contrast and improve the communication quality in the spatial optical communication. This method satisfies the request of real-time processing in communication, and is also effective and practical. practical.