Environmental Noise Cancellation (ENC): Part 2 - Noise types and classic methods for Speech Enhancement

By _Ceva's Experts blog

April 27, 2023

In part 1, we discussed some important concepts related to sound processing and environmental noise cancellation that are essential to keep in mind when designing an ENC (Environmental Noise Cancellation) system. Now, let’s talk about the rest of the equation, which is the noise itself. In this section, we will characterize common noise types and explore some of the classical speech enhancement methods that are commonly used to tackle this problem.

Researchers typically categorize noises as either stationary or non-stationary, depending on different characteristics. Understanding the differences between these two types of noise can provide valuable insights into their properties and ways to deal with them.

Stationary noise refers to noise that remains relatively constant in its statistical properties over time. In other words, its statistical characteristics such as mean, variance, and autocorrelation remain constant or change only slightly over time. Common examples of stationary noise include the hum of an air conditioner or the constant hum of a refrigerator. Stationary noise can often be easily characterized and analyzed using mathematical techniques, making it suitable for various analytical algorithms to predict and cancel.

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