Analysis and sound synthesis for human echolocation

Abstract: Human echolocation is the way in which people use information in echoes to detect objects and locate themselves. Previous research were done in order to investigate this complex processing. One on-going research is based on empirical results of both blind and sighted people, and tries to set up the relations between behavioral data and physical analysis. Repetition pitch and loudness are two of the mechanisms which human echolocation is based on. People’s perception of repetition pitch and loudness has been found to be strongly related to autocorrelation and the root mean square value of the sound signal respectively. This thesis project was conducted in order to analyze the relevant information in previously made sound recordings. By comparing theoretical results, some important sound properties were identified. Colorations in the original sound recordings were found to be able to influence participants’ judgments on echoes. An acoustic model was set up in order to synthesize sound recordings with pre-defined properties. Physical results of autocorrelation and root mean square value of the synthesized sound signals were validated to follow the theoretical expectations. Discussions and proposals were made in order to further improve the sound syntheses’ correspondence to physical recordings. The main achievements in this thesis project were to provide analysis from signal processing’s point of view in order to identify sound properties, to investigate relations between physical results and empirical results of human echolocation and to propose an acoustic model to synthesis sound.