## What is Noise in Machine Learning

Real-world data, which is used to feed data mining algorithms, has a number of factors that can influence it. The existence of noise is a major factor in both of these problems. It’s an inevitable problem, but one that a data-driven organization must fix.

Humans are prone to making mistakes when collecting data, and data collection instruments may be unreliable, resulting in dataset errors. The errors are referred to as noise. Data noise in machine learning can cause problems since the algorithm interprets the noise as a pattern and can start generalizing from it.

**A noisy dataset will wreak havoc on the entire analysis pipeline. Noise can be measured as a signal to noise ratio by analysts and data scientists**

As a result, by using an algorithm, any data scientist must deal with the noise in data science.

**Machine learning noise detection**** and removal**

There are many widely used techniques used to extract the noise from any signal or dataset.

## Principal Component Analysis

PCA is an arithmetic technique that employs the orthogonal property to convert a collection of potentially correlated variables into unrelated variables. The term “principal components” refers to these new variables.

**PCA attempts to eliminate corrupted data from a signal or picture using preservative noise while maintaining the critical features**

PCA is a geometric and statistical method that reduces the input signal dimension or data by projecting it along various axes. To better understand, imagine projecting a point in the XY dimension along the X-axis. The noise plane – Y-axis can now be removed. The phenomenon is referred to as “dimensionality reduction.” As a result, by eliminating the axes containing the noisy data, principal component analysis can minimize the noise in input data.

## Deep De-noising

Auto-encoders are useful for de-noising; a stochastic variant of auto-encoder is available. Since they can be trained to recognize noise detection in a signal or data, they can be used as de-noisers by feeding them noisy data and receiving clean data as an output. Auto-encoders are made up of two parts: an encoder that converts input data into an encoded state, and a decoder that decodes the encoded state.

**A de-noising auto-encoder does two things: it encodes the input while retaining as much detail about the output as possible. It also reverses the effects of stochastically added noise to the input data**

De-noising auto-encoders’ main goal is to push the secret layer to learn more robust features. The auto-encoder is then trained to reconstruct the input data from the degraded version while reducing loss. The use of auto-encoders to eliminate noise from a signal is demonstrated in one example.

## Contrastive dataset

Assume you need to clean a noisy dataset that includes big background patterns as noise that a data scientist isn’t interested in. Then, using an adaptive noise cancellation approach, this method offers a solution by eliminating the noisy signal. This technique employs two signals: one is the target signal, and the other is a noise-free background signal.

## Fourier Transform

Researches have already shown that our signal or data has a structure, we can remove noise from it directly. The Fourier Transform of the signal is used to translate the signal into the frequency domain in this process.

We won’t see this impact in raw signal or data, but if you break down the signal into a frequency domain, you’ll notice that the majority of the signal information in the time domain is represented by just a few frequencies. Since noise is unpredictable, it will be dispersed through all frequencies.

According to the theory, we can filter out the majority of the noisy data by keeping the frequencies that contain the most important signal information and discarding the rest. It is possible to remove noisy signals from the dataset in this manner.

## Conclusion

Separating the signal from the noise is a major concern for data scientists these days because it can lead to performance problems, such as overfitting, which causes the machine learning algorithm to behave abnormally. An algorithm can use noise as a starting point for generalization. As a result, the safest way is to eliminate or reduce the noisy data in your signal or dataset.