- Naive Bayes
- Natural Language Processing (NLP)
- Nearest Neighbor
- Negative Sampling
- Network Compression
- Network Science
- Network Topology
- Network Visualization
- Neural Architecture Search
- Neural Collaborative Filtering
- Neural Differential Equations
- Neural Machine Translation
- Neural Networks
- Neural Style Transfer
- Neural Tangent Kernel
- Neuroevolution
- Neuromorphic Computing
- Node Embedding
- Noise Reduction Techniques
- Non-autoregressive models
- Non-negative Matrix Factorization
- Non-parametric models
- Nonlinear Dimensionality Reduction
- Nonlinear Regression
- Nonparametric Regression
- Normalization
- Novelty Detection
- Numerical Methods
- Numerical Optimization

# What is Noise Reduction Techniques

##### Noise Reduction Techniques: An Overview

Noise is the unwanted electrical signal that interferes with the desired signal in signal processing systems. This noise can be caused by a variety of factors including thermal noise, white noise, and electromagnetic interference. To minimize the impact of noise on signal processing systems, several noise reduction techniques have been developed.

In this article, we will explore some of the popular noise reduction techniques and their applications.

**1. Low Pass Filters**

A low pass filter is a type of electronic filter that allows low-frequency signals to pass through while attenuating high-frequency signals. In signal processing, low pass filters are used to eliminate high-frequency noise from a signal. One of the most common types of low pass filters is the Butterworth filter, which is used to achieve a flat passband and a reasonably sharp cutoff. Other types of low pass filters include Chebyshev filters and Bessel filters.

**2. High Pass Filters**

High pass filters are the opposite of low pass filters, allowing high-frequency signals to pass through and attenuating low-frequency signals. In signal processing, high pass filters are used to eliminate low-frequency noise from a signal. High pass filters are commonly used in audio systems and image processing systems to remove low-frequency noises such as rumbling sounds in audio systems and blurring in images.

**3. Band Pass Filters**

A band pass filter is a type of electronic filter that allows a certain range of frequencies to pass through while attenuating other frequencies. In signal processing, band pass filters are used to eliminate unwanted frequencies and retain the desired frequency band. A band pass filter is often used in audio systems to filter out noise and retain the desired frequency band of music or speech.

**4. Notch Filters**

A notch filter is a type of electronic filter that attenuates a narrow range of frequencies while allowing other frequencies to pass through. In signal processing, notch filters are used to eliminate a specific frequency or a narrow range of frequencies that interfere with the desired signal. Notch filters are commonly used in audio systems to eliminate humming and buzzing noises caused by electrical interference.

**5. Wiener Filters**

Wiener filters are an advanced type of noise reduction technique that uses statistical signal processing to remove noise from a signal. Wiener filters are based on the assumption that both the noise and the desired signal are stochastic processes with known spectral characteristics. The Wiener filter then calculates the optimal reduction of the noise based on the spectral characteristics of the noise and the desired signal. Wiener filters are commonly used in image processing applications where the desired signal is an image and the noise is an unwanted interference.

**6. Wavelet Filters**

Wavelet filters are a type of filter that can decompose a signal into multiple, non-overlapping frequency bands. The wavelet filter bank can then be used to selectively remove certain frequency bands based on the desired filtering result. Wavelet filters are commonly used in audio and image processing applications to remove unwanted noise and retain the desired signal.

**7. Kalman Filters**

Kalman filters are a type of noise reduction technique that uses a mathematical model of a system to estimate the system's state. The Kalman filter then optimally combines noisy measurements of the system with the predicted system state to estimate the true system state. Kalman filters are commonly used in control systems and navigation systems to estimate the position and velocity of a system in the presence of noise.

**Conclusion**

Noise reduction techniques are essential for eliminating unwanted signals in signal processing systems. There are several types of noise reduction techniques, including low pass filters, high pass filters, band pass filters, notch filters, Wiener filters, wavelet filters, and Kalman filters. Each of these noise reduction techniques has its unique advantages and applications. By using these techniques, we can reduce the impact of noise on a signal and improve signal quality.