Speech enhancement in hearing aids - from noise suppression to rendering of auditory scenes

In this paper we review state-of-the-art signal processing technologies for enhancing speech and audio signals in hearing aids and assess their benefits and their potential for the purpose of acoustic scene analysis and synthesis. We discuss single and multi microphone techniques for source detection, localization, classification, and enhancement and we emphasize the need for rendering enhanced output signals which provide a consistent and natural mapping of the acoustic environment. Despite considerable progress in many relevant areas we argue that this requires a processing framework which goes much beyond the current signal processing approaches and in fact requires the fusion of sound field analysis, signal enhancement techniques and binaural rendering approaches.