A novel optical signal detecting and processing method for swarm robot vision system

Communication capability plays an important role in the robot swarm systems (RSS), especially when they are used as soldiers during a war. Free space optical (FSO) communication is one of the best ways to exchange information between the leader and the followers in the RSS under a bad electromagnetic condition. It can be integrated as a part of the robot vision system (RVS). Pulse position modulation (PPM) is one of the most often used modulation techniques for FSO communication. As avalanche photodiode (APD) detector has high gain, high sensitivity and high response speed, it is a likely candidate to detect laser signals to meet the demands of RVS. This paper discusses the characteristics of noises in the optical signal detecting and processing subsystem as the PPM signal is considered in the RVS. Based on the ability of achieving topical characteristics of signals of wavelet transform, this paper brings forward a novel method of processing the APD detecting signals based on wavelet analysis. The soft threshold σ·√(2 log (n)/a) is used to process the empirical wavelet coefficients. A primary simulation experiment and some analysis results are given.