SIGNAL PROCESSING STRATEGIES FOR COCHLEAR PROSTHESIS

本研究的长期目标是改善目前人工耳蜗信号处理策略的语音性能。 本研究将提出一系列策略，这些策略将使用感知上与输入信号“最接近”的信息来刺激电极。在这些策略中，选择通道幅度，使得刺激（电）模式和声学模式之间的差异最小化，即，通过优化感知激励误差标准来选择通道幅度。 两种类型的错误的标准将进行调查，时间标准，它强调了包络信息的重要性，和频谱标准，它强调了频谱信息的重要性。拟议的实验有三个具体目标。 第一个目的是调查是否有一个更好的频谱匹配的策略设计的语音识别任务比传统的连续交错采样（CIS）的战略。 第二个目的是了解光谱信息对Med-El和Nucleus人工耳蜗植入设备的单词识别的重要性。 为了实现这一目标，我们将提出植入病人的句子从TIMIT语音语料库中的元音或辅音将被替换为白色噪音。 第三个目的是调查是否设计更好的波形匹配的策略比CIS策略在语音识别任务上表现更好。 所提出的策略将在便携式语音处理器上实施，并将在人工耳蜗植入患者中进行测试。 这些调查的结果将奠定基础，更好地了解哪些信息，时间（包络）或频谱，是感知更重要的人工耳蜗植入。最重要的是，它将为人工耳蜗未来信号处理策略的发展开辟新的途径。

The long term objective of the proposed research is to improve the speech performance of current signal processing strategies for cochlear prosthesis. The present study will propose a series of strategies which will stimulate the electrodes using information that is "closest", perceptually, to the input signal. In these strategies, the channel amplitudes are selected such that the difference between the stimulating (electrical) pattern and the acoustic pattern is minimized, that is, channel amplitudes are selected by optimizing a perceptually motivated error criterion. Two types of error criteria will be investigated, a temporal criterion, which emphasizes the importance of envelope information, and a spectral criterion which emphasizes the importance of spectral information. The proposed experiments have three specific aims. The first aim is to investigate whether a strategy designed for better spectral matching performs better on speech recognition tasks than the conventional Continuous Interleaved Sampling (CIS) strategy. The second aim is to understand the importance of spectral information on word recognition with the Med-El and Nucleus cochlear implant devices. To accomplish this aim, we will present to implant patients sentences from the TIMIT speech corpus in which the vowels or the consonants will be replaced with white noise. The third aim is to investigate whether a strategy designed for better waveform matching performs better on speech recognition tasks than the CIS strategy. The proposed strategies will be implemented on a portable speech processor and will be tested with cochlear implant patients. The results of these investigations will lay the groundwork for a better understanding of which information, temporal (envelope) or spectral, is perceptually more important for cochlear implants. Most importantly, it will open new avenues for the development of future signal processing strategies for cochlear prosthesis.