De-noise Comprehensive Research On Airplane Cockpit Signals Recorded by CVR

The characteristic of cockpit sound recorded by CVR is the key evidence in investigating accident causes for wrecked aircraft. However, cockpit signals ( or CVR sound information) are complex, they include crew's voices (or pilot's voices), environmental noise and different kinds of backgrounds sound signals , and many factors from inside and outside cockpit affects the analysis results, especially noise. To obtain the pure cockpit signal (no noise) from mixed cockpit signals, after CVR Signals' classification, the comprehensive de-noise research for cockpit signals are made, including the DWT threshold de-noise, the cockpit sound' ICA de-noising based on BSS and wavelet de-noise are put forward. Through different de-noise methods comparative research for cockpit signals, some valuable conclusion can be drawn in the end of the paper. These conclusions are very useful for judging and diagnosing the wreckage aircraft by pure cockpit signals (background sound signals). Index Terms-Information process; airplane; Blind Source Separation (BSS); Independent Components Analysis (ICA); Cockpit signals