Howling Detection in Hearing Aids Based on Generalized Teager–Kaiser Operator

With the ongoing miniaturization in the hearing aid industry, acoustical coupling between the loudspeaker and the microphone(s) of the hearing aid causes a major problem to users. Howling is one of the most severe and annoying consequences of this acoustical coupling. This study presents a howling detection method using the Generalized Teager-Kaiser Operator (GTKO). Since the GTKO is both time and frequency sensitive, its resolution parameter must be assigned properly to ensure satisfactory performance of this operator in the frequency range of the input signal for the hearing aid. In order to cover the entire band of the input signal with appropriate resolution parameters, the input signal is decomposed into a filterbank (i.e., uniform and nonuniform filterbanks). GTKO is applied to the output of each band to detect the howling, and the resolution parameter of the GTKO block is selected depending on the central frequency of that particular band. Experimental results compare the performance of each proposed method with two known howling detection approaches, Peak-to-harmonic power ratio (PHPR) approach and a multiple-feature approach. The proposed method has high detection probability and short detection time. It is also shown that considering a hybrid algorithm which includes the PHPR approach with each of the proposed methods (i.e. combination of GTKO blocks with different types of filterbanks) results in lower false alarm probability.