International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 3 | Mar -2017
p-ISSN: 2395-0072
www.irjet.net
Review Paper on Noise Reduction Using Different Techniques 1Pooja
G Prajapati, 2Anupam N Devani
1Dept.
of Electronics & Communication Engineering, Shantilal Shah Engineering college, Bhavnagar Gujarat, INDIA 2 Professor, Dept. of Electronics & Communication Engineering, Shantilal Shah Engineering college, Bhavnagar Gujarat, INDIA ---------------------------------------------------------------------***-------------------------------------------------------------------
sounds again, and then improve their listening level. With the microchips available today, hearing aids have gotten smaller and smaller and have significantly improved quality.
Abstract –Nowadays there are many people affected by
hearing impairments. The main complaint of people with hearing loss is low ability to deduce speech in a noisy environment. Hearing aid is a device, which can acquire, process and feedback acoustic signal in real time. In this matter various impedance matching algorithm, various filter bank techniques, signal processing algorithm and echo cancellation are discussed. The purpose of this work is to develop the digital signal processing based platform for digital hearing aid application, which is for the people with hearing impairment using the low cost orange pi model. To Perform this Application FFT algorithm is used which is quite easy to implement and required less computation. The algorithms are performed using python language which gives the best clarity and functionality over MATLAB.
Digital hearing aids have a series of advantages: they can acquire a high signal-to-noise ratio, can change the gain dynamically, adjust resistance to electromagnetic interference adaptively, eliminate feedback, and have been widely concerned worldwide. But in the real environment, a variety of noises are encountered, the performance of voice system under noise environment would drop dramatically or even completely fail, therefore the noise reduction performance of a voice system is critical to evaluate the quality of a hearing aid. Improving the speech comprehension under the noise environment has been the bottleneck of enhancing the performance of hearing aids. At present, improving methods mainly include two categories: directional microphone and noise reduction algorithm [2]. The former is designed based on the differences of speech and noise in the space, and utilizes directional microphones or beam forming technology to enhance the speech signal characteristic in the specific direction. But the improvement of this method is limited by the number or size of microphones, and does not apply to complete in the canal (CIC) hearing aids. The second way is separating the speech from noise by using differences of time and frequency spectrum between noise and speech. However, the speech and noise may overlap in time and frequency spectrum, so the noise reduction effect remains to be furtherly researched. Noise reduction performance is directly related to whether the wearer can hear really useful speech, even affects the physical and mental health of hearing-impaired patients [1].
Key Words: Hearing aid, Noise Reduction, SNR, Fast Fourier Transform
1. INTRODUCTION The intelligibility of human speech plays an important role in communication. It is both a measure of comfort and comprehension. The quality and intelligibility of the speech are not only determined by physical characteristics of the speech itself but also by communication conditions and information capacity, the ability to get the information from context, mimics and gestures. When discussing intelligibility it is important to understand the difference between a real and recorded speech. During a real conversation a person can recognize the surrounding sounds and concentrate on the speech of another person thus filtering the desired information out of various audio environments. Therefore the ability of a human to recognize and filter sounds significantly increases the intelligibility and comprehension of the speech even if a communication takes place in a noisy environment, situation or condition [2].
Digital hearing aids are committed to minimize the negative impact of the noise, basically have the function of smart noise reduction. However the noise reduction effect of various types of hearing aids differ in thousands ways, which requires the establishment of a complete measurement system to evaluate the noise reduction performance of hearing aids, eventually help hearingimpaired persons to choose suitable hearing aids.
Hearing aid is a small electronic instrument which makes sounds louder and makes speech easier to hear and understand, it is designed to pick up sound waves with a tiny microphone, change weaker sounds into louder sounds, and send them to the ear though a tiny speaker, so that it can help patients with hearing loss to perceive
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