On the Application of the De-noising Method of Stationary Wavelet Coefficients Threshold to Filter Out Noise in Digital Hearing Aids
Date Issued
2010
Date
2010
Author(s)
Liu, Chia-Chou
Abstract
For a long time, improving the hearing of the hearing-impaired has been what researchers and medical professionals been struggling to achieve. Because there are currently over 200 million deaf or hard of hearing people worldwide, researchers and medical professionals realize the importance of this goal. Fortunately, the gift of technology, from early analog hearing aids to the mainstream of digital hearing aids, has brought about various kinds of flourishing digital signal processing technology. The function of current hearing aids is no longer restricted to just simple voice amplification, which allows the hearing-impaired to hear directly, but can also satisfy the different needs of different users with different sound signal processing. In fact, the development of hearing aids still has an opportunity for improvement.
In this paper, the white noise is added to the clean voice signal, becoming a voice signal that contains noise. First, the discrete wavelet transform is used to cut the voice bandwidth into nine different sub-band bandwidths. Second, the discrete wavelet stationary transform is used to cut the voice bandwidth into nine different sub-band bandwidths. Third, the wavelet packet transform is used to cut the voice bandwidth into eight identical bandwidths. The wavelet de-noising method is used to filter out high-frequency noise. After the voice signal has been de-noised, it makes up four different types of hearing loss, including 40dB uniform hearing loss, mild low-frequency hearing loss, moderate high-frequency hearing loss, and severe high-frequency hearing loss. Finally, the saturated volume limits the final output of the energy of speech to a fixed size. This thesis is to simulate voice signal processing by the wavelet transform. The process of verification can effectively filter out white noise, and compensate the four different types of hearing loss to achieve the basic functions of digital hearing aids.
Subjects
Digital hearing aids
discrete wavelet transform
discrete stationary wavelet transform
wavelet packet transform
wavelet de-noising method
SDGs
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-99-R97525064-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):dcf062faaeedff9ab1087aa28012e838