Simpson A M, Moore B C, Glasberg B R
Department of Experimental Psychology, University of Cambridge, England.
Acta Otolaryngol Suppl. 1990;469:101-7.
At speech-to-noise ratios between -3 and 6 dB, many hearing-impaired listeners have difficulty in understanding speech, but spectrograms reveal that the formant peaks of voiced speech and some of the spectral peaks associated with unvoiced speech stand out against the background noise. Our speech-enhancement process is based on the assumption that increasing spectral contrast will result in improved intelligibility. The enhancement involves calculating an auditory excitation pattern from the magnitude spectrum of overlapping short segments of the speech signal. This pattern is convolved with a difference-of-Gaussians function whose bandwidth varies with frequency in the same way as the auditory filter bandwidth. Magnitude values from this enhanced pattern are combined with the unchanged phase spectrum from the original signal to produce the enhanced speech. The processing was used to enhance Boothroyd and Bench-Kowal-Bamford Audiometric lists which had been digitally combined with speech-shaped noise at speech-to-noise ratios between -3 and 6 dB. The subjects had moderate to severe sensorineural hearing losses. The processing produced small but significant improvements in intelligibility for the hearing-impaired listeners tested. Possibilities for improving the processing are discussed.
在语音与噪声比为-3至6分贝之间时，许多听力受损的听众在理解语音方面存在困难，但频谱图显示，浊音语音的共振峰以及一些与清音语音相关的频谱峰值在背景噪声中较为突出。我们的语音增强过程基于这样一种假设，即增加频谱对比度将提高可懂度。增强过程包括从语音信号重叠短片段的幅度谱计算听觉激励模式。该模式与高斯差分函数进行卷积，其带宽随频率变化的方式与听觉滤波器带宽相同。此增强模式的幅度值与原始信号不变的相位谱相结合，以产生增强后的语音。该处理方法用于增强Boothroyd和Bench-Kowal-Bamford听力测试列表，这些列表已在语音与噪声比为-3至6分贝的情况下与言语噪声进行数字组合。受试者患有中度至重度感音神经性听力损失。对于所测试的听力受损听众，该处理方法在可懂度方面产生了虽小但显著的改善。文中还讨论了改进该处理方法的可能性。
