Method for the binaural left-right localization for hearing instruments

摘要

A method and system for improving signal-to-noise ratio of output signals of a microphone system having two or more microphones due to acoustic useful signals at sides of the system are used in hearing instruments, especially hearing aids worn on the head. High and low frequency portions (cut-off frequency between 700 Hz and 1.5 kHz, approx. 1 kHz) are processed differently. In low frequency ranges, differential microphone signals directed towards left right are produced to determine lateral useful and noise sound levels using these two directional signals. These levels are used for subjecting every microphone signal to individual Wiener filtering. The natural head shadowing effect is used in high frequency ranges as a pre-filter for noise and useful sound estimation for subsequent Wiener filtering. The methods are used in hearing instruments worn on the head individually for high or low frequencies or in combination and complement each other.

主权项

1. A method for improving a signal-to-noise ratio of laterally occurring acoustic useful signals, the method comprising the following steps:
capturing acoustic signals with at least two microphones of a microphone system, one microphone being closer to a source of the acoustic signals than the other microphone; specifying one spatial direction as a useful signal direction and one spatial direction as a noise signal direction; determining a noise signal by differential processing of output signals from the microphone system, and achieving a lower sensitivity in the useful signal direction than in the noise signal direction; determining a useful signal by differential processing of the output signals from the microphone system, and achieving a higher sensitivity of the microphone system in the useful signal direction than in the noise signal direction; determining a noise signal level in dependence on the noise signal; determining a useful signal level in dependence on the useful signal; and defining an amplification factor for amplification of acoustic signals captured by the microphones in dependence on the noise signal level and the useful signal level.