Method for reducing interference in acoustic signals using an adaptive filtering method involving spectral subtraction

A method for reducing interference in disturbed acoustic signals using an adaptive filtering process including spectral subtraction, the method comprising:

• filtering the signals in a plurality of respective time segments and a plurality of respective discrete frequencies i segmentwise using an adaptive filtering function;
• determining a respective noise-input ratio for each of the plurality of respective time segments and respective discrete frequencies so that each respective noise-input ratio has a small respective value for signals having a relatively low disturbing noise component and a high respective value for signals having a relatively high disturbing noise component;
• adapting the adaptive filtering function so that respective information on a respective a priori signal-to-noise ratio is used for a calculation of each of a plurality of characteristic values of the adaptive filtering function;
• and
• using at least one of the plurality of characteristic values from a respective at least one preceding time segment as the respective information on each respective a priori signal-to-noise ratio;
• the adaptive filtering function having a characteristic curve including two parts and having a break edge positioned such that the filtering for signals having a high respective noise-input ratio results in a signal-independent relatively strong damping and the filtering for signals having a low noise-input ratio results in a signal-dependent relatively low damping.