A solution of front-back confusion within binaural processing by an estimation method of sound source direction on sagittal coordinate

There are many proposals for binaural processing models and their applications for a hearing assistance system. These models attracts attention because of their directional selectivity in frontal direction of user. Not only binaural models but also any of two-element array system have a well know ambiguity in front-back discrimination which is called as “front-back confusion” or called as “cone of confusion” in psychoacoustics. Recently it was found that spectral cue of sound provides keys to solve this confusion in binaural listening condition and it was also reported the peaks and notches of spectral components play main role to estimate the vertical angle in sagittal coordinate. In this paper, a new method to estimate sound source direction on sagittal coordinate is proposed in order to solve the front-back confusion. It is implemented on an artificial neural network using interaural level and phase differences as input. The results of simulation using a set of Head Related Transfer Function of dummy head show that the averaged estimation error in quadrant segmentation is less than 1.0% for various types of sound.