ỨNG DỤNG WAVELETS VÀO XỬ LÝ TIẾNG ỒN

Abstract

Noise is a concept that is constantly present in our lives, and the study of noise treatment has become an important practical issue. In this article, we will discuss a noise treatment method through wavelet analysis and synthesis algorithms combined with ANC active noise control technology. Active noise control (ANC), also known as noise cancellation (NC), or active noise reduction (ANR), is a method of reducing unwanted sound by adding a second, specially designed sound to cancel out the first sound. ANC uses special equipment to listen to ambient noise and then generate a second audio signal that has all the characteristics but is in the opposite phase to those noises. By the principle of interference, when the two opposite signals are combined, the noise will be canceled. Wavelets are a very suitable tool for us to generate this second signal. Wavelets are wave-like oscillations whose amplitude starts at zero, increases or decreases, and then returns to zero one or more times. Wavelets are colloquially known as "small waves". Wavelets are classified based on the number and direction of their pulses. Wavelets have specific characteristic properties that are very useful for signal processing.