Bio-inspired camouflage communication in air imitating birds songs

Abstract

Radio communication is the most common means of communication nowadays, however, radio interference technology is becoming mature. Once radio communications are disrupted in the forest, people would be left in a passive position without any effective communication method. Sound is an also effective carrier of information. To realize effective communication in the forest environment, we proposed a bio-inspired camouflage communication strategy(BCCS) by imitating bird songs and took the Verditer Flycatcher as an example to demonstrate the feasibility of BCCS. We proposed a compound characteristics grouping coding method based on the tree structure to divide syllables into 32 feature groups. And five time–frequency(T-F) characteristics of syllables were extracted as grouping layers: syllable length, average frequency, frequency trend, the standard deviation of global frequency, and the difference of local frequency standard deviations. Then the correlation was used as the unique identification of a syllable within the group. Syllables in the feature group were screened to ensure high autocorrelation and low cross-correlation, which are the key basis in decoding. Each individual syllable can encode 8 bits of binary information through compound characteristics coding and correlation coding. Since the communication sequence is completely composed of the original bird songs and follows the regularities of distribution, BCCS has a good camouflage ability. Experiments were carried out to verify the feasibility and camouflage ability of BCCS in the forest environment.