"Two Ears Are Better Than One": Towards the Development of a Real-Time Crosstalk Cancellation System Based on Bone Conduction

对于那些无法从常规空气传导助听器中受益的耳部问题，骨传导助听器是一种有价值的替代方案。然而，当“串扰”发生时，预期用于一只耳朵的声音通过骨传导（BC）无意中到达对侧耳朵。这种不期望的声音传输会限制使用两个这样的设备的双耳优势。我们的项目旨在开发一种基于BC的串扰消除系统，以改善双耳听觉体验。于2022年，我们专注于以下方面：（1）识别有效的耳内传感器以消除串扰：我们使用纯音听力阈值评估耳内传感器对耳蜗水平消除的贡献最大，有和没有串扰消除。我们的研究结果表明，使用探针麦克风提供了更好的结果。(2)检查传感器放置对取消成功的影响：我们探讨了耳道（探头麦克风）和乳突（加速度计）的位置。更靠近内耳的传感器放置导致更好的感知消除。(3)确定用于消除的最佳声音频率范围：由于难以接近，我们的目标是在传感器上消除串扰，而不是耳蜗。这种抵消仍然到达耳蜗，但证明仅在低频下有效。(4)开发实时单边串扰消除原型：我们在Bela Mini音频平台上实现了我们的方法，使用简单的GUI实现了消除。我们的系统以低延迟实时运行。演示视频可在线访问https://youtu.be/D-Oy1AyythQ

For those with ear issues unable to benefit from regular air conduction hearing aids, bone conduction-based hearing aids serve as a valuable alternative. However, when "crosstalk" occurs, sound intended for one ear inadvertently reaches the opposite ear through bone conduction (BC). This undesired sound transmission can limit the binaural advantages of using two such devices. Our project aims to develop a BC-based crosstalk cancellation system that improves binaural listening experiences. In 2022, we focused on the following aspects:(1) Identifying effective in-ear sensors for crosstalk cancellation: We assessed in-ear sensors contributing most to cochlear-level cancellation using pure-tone hearing thresholds, with and without crosstalk cancellation. Our findings revealed that using a probe microphone provided better results.(2) Examining sensor placements' impact on cancellation success: We explored the ear canal (probe microphone) and mastoid (accelerometer) locations. Sensor placement closer to the inner ear resulted in better perceived cancellation.(3) Determining optimal sound frequency range for cancellation: We targeted crosstalk cancellation at the sensor, not the cochlea, due to inaccessibility. The cancellation still reached the cochlea, but proved effective only at low frequencies.(4) Developing a real-time unilateral crosstalk cancellation prototype: We implemented our method on the Bela Mini Audio Platform, with a simple GUI enabling cancellation. Our system operated in real-time with low latency. A demo video is available online at https://youtu.be/D-Oy1AyythQ