# Tagged Questions

In signal processing noise can be considered random unwanted data without meaning.

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### noises are continuous or discrete in nature? what are the types of statistical noise? and why it is called as statistic noise? [on hold]

i saw in Wikipedia that only white and Gaussian noise are considered as statistical noise. why cant other noises considered as statistical noise
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### generating white gaussian noise in matlab using two different functions

I want to know the difference between the two Gaussian noises generated below? Which one is white and how can i make the other one white? y=wgn(1,10000,0) and ...
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### Noise removal of an audio signal (.wav) using matlab [on hold]

I was given an audio file containing noise. It's required to find the noise frequency components and then remove them. Finally play the noise free audio signal. Here's what I did so far: ...
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### Image averaging for impulse noise

I understand the mathematics behind the use of image averaging for gaussian noise. Why can't it be used for impulse noise ? Would it be because there is no way to prove that impulse noise is additive ...
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### Segmentation of small artifacts - Image Processing

I am working on a task of segmenting small artifacts from a set of images like below: I am looking for a generic approach, but unsure of what to search? I tried looking at density flow analysis, but ...
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### Resources on Non-Gaussian Channels

I understand why most of the classic textbooks only consider Additive White Gaussian Noise channels in digital data transmission. Unfortunately in my case noise is not Gaussian and it might even be ...
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### What is the difference between a'mixer' and a ' multiplier' used in modulation process?

I am not sure if it is valid to conclude that a mixer produces a difference/sum of frequencies at output ,while multiplier produces multiples of frequency at its output. I am keen to know how far I ...
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### Sox, mixing mono inputs into mono output (efficiently)

I want to mix two mono files, signal.wav and noise.wav, into a single mono file, signal_noise_mono.wav. Currently, I know how to mix the two input files into a stereo file and then remix it to mono, ...
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### Should S-Matrix components for scattering response in a Polarimetric Radar be Real or Complex?

I am trying to implement some polarimetric decomposition algorithms on my MIMO polarimetric radar. At first, I will try the Pauli Decomposition algo. But instead of doing signal processing on the ...
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### Filter for noisy accelerometer data

I tried to read up and get a filter for a 3-axis accelerometer but this is more confusing than I thought. I have an IMU with a 3-axis accelerometer on the end of a robot link which is rotated around ...
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### Calculation of an autocorrelation function

A sample of a random process is given as: $$x(t) = A\cos(2\pi f_0t) + Bw(t)$$ where $w(t)$ is a white noise process with $0$ mean and a power spectral density of $\frac{N_0}{2}$, and $f_0$, $A$ ...
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### Audio Broadband Noise Detection

I have to quantify the broadband noise of an audio track. I've seen lots of things around and the only viable option to estimate the broadband noise (without having any information about it) is ...
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### Looking for low-noise audio data to benchmark some noise-processing techniques

I'm looking for a source of very low-noise audio data for use in benchmarking various methods of random noise correction methods. My intention is to have a very clean signal to which I can add known ...
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### Finding the Amplitude of a Sinusoid in Noise

I'm trying to solve for the amplitude and frequency of a sinusoid embedded in zero-mean gaussian white noise. I am supplied a sample file of a 40000 element array. I first took the autocorrelation ...
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### Noise Robust Linear Prediction

So it appears that Linear Prediction as performed via Durbin Recursion is sensitive to additive noise. What are some techniques for linear prediction that may be more robust? Can anyone supply a link ...
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### Fourier transform of a Fourier transform

I generate a Gaussian noise and then I filter it with a passband FIR Kaiser window filter. When I perform the Fourier transform of the output of the filter and plot its magnitude spectrum, it is ...
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### In signal averaging, will the noise be reduced if the noise is not Gaussian?

My understanding is that signal averaging works this way. If we take the average of the waveform, we get the average of the signal component (which is the magnitude of the signal) and the average of ...
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### 1/f noise parameter characterization

I would like to characterize 1/f noise in some time series data. I would like to estimate the 1/f noise corner, and the standard deviation of the 1/f noise component and white noise component. The ...
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### Generating 3-dimension $1/f^\alpha$ noise

I'm stumped trying to find a way to generate a 3-dimensional $1/f^\alpha$ noise time series. Basically I want simulate a forcing that is $1/f^\alpha$ in the 2 space dimensions and $1/f^\beta$ in time, ...
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### Adding two audio files at a predefined SNR level

I have two speech audio wav files. file1 is primary speech, file2 is supposed to be interference. I want to add them so that ...
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### Adding “realistic” noise to signals of different amplitudes

I have a question regarding basic signal processing, which I have to start using since I have started studying fault isolation. The thing is, I have three computed signals, which are gathered in the ...
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### Approximation of Step Response from Data with delay

How can I approximate a Step Response curve from a measured data of a single input and a single output using Matlab while the delay between the input and the output is 30 minutes?
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### How to measure noise, consonance, dissonance of a sound?

How can I make a graph of the noisiness of some audio durations of 100ms - 10s with 100% being white noise and 0% being a sine wave. I have FFT at the moment, are there other ways to know the ...
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### Determine whether a signal is increasing or decreasing over time

I have a signal (x-axis: Time, y-axis: Data) which has more than 10000 samples per second. The signal itself represents some physical data (e.g. speed, acceleration, etc.) and has some noise on it. ...
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### What does it mean by “Adding Gaussian Noise to a 2D Image”? [duplicate]

As far as I understand, Suppose, we have a 2D image of pixel resolution 200 x 300. That means, the image has 60000 pixels in it. Now, we would generate $n$ random values and add those values to $n$ ...
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### Why is Gaussian noise called so?

Can you please explain: why is a specific type of noise called "Gaussian noise"? Why is it relevant to call it Gaussian? Please, explain in layman's terms.
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### What would produce this “hamburger” corruption on images?

I have an image that has gone through an unknown number of jpeg and webp conversions (at least one but more likely 2+). Currently this image is a JPEG and contains corruptions in single color or mild ...
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### How to know if there is noise affecting my signal

I have a signal shown in the attached figure and the fft of that signal as well. In addition I have also attached the fft of the static noise signal. You can see that in the original signal there are ...
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### Detecting outliers/noise from sensor data

I am trying to detect outliers/noise as indicated on the diagram below from sensor data. Can anyone advice how to go about it? I can only do this in python, so are there libraries in python that I can ...
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### Which are the known techniques to filter noise from time series?

this is not a specific question. I would like to know the known techniques to filter noise or make a noise reduction, in specific, from time series, but can be other type of data with wave format and ...
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### Double Integrating Gaussian Noise

My question has to do with integrating gaussian noise. Let us assume we have samples of discrete gaussian white noise with mean $\mu = 0$ and variance $\sigma_{th}^2$. These noise samples are passed ...
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### Numerically generating noise time series from spectral density

I'm trying to figure out a way to construct (numerically) time series of random variables given some spectral density $S_{xx}(f)$. I'm interested in various types of spectral densities (flat, ...
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### Periodic noise attenuation

I have continuous data with very high amplitude periodic noise. Data is sampled at 500 Hz. The period of the noise does change with time but within a short interval (~ a minute) it is constant. Top ...
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### approach to differentiate noisy data with steep ramp

I'm trying to write some image processing code in python to differentiate between two types of images (we'll call them set Blue and set Amber). I have run an algorithm I wrote that results in the ...
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### Convert sine wave signal to square wave signal

I have a signal containing a variation of digital ASK type on-off keyed sine wave among which some stochastic irrelevant harmonic waves occur, like you can see on this figure: In its current form ...
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### Fourier transform of Image to identify sinusoidal sources of interference

I'm a statistics grad student, and I just started getting into Digital-Image-Processing (an analogy for processing super-large contingency tables). In the book "Digital Image Processing" by Gonzalez ...
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### Matlab signal processing removing white noise from signal

What is the way to address the removal of white noise from a signal? Extra Details Hi I also agree the details are as follow: ...
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### white noise in images

For digital images, noise is assumed to be additive gaussian white noise. I remember noise in images is considered as high frequency. However, from the link https://en.wikipedia.org/wiki/White_noise, ...
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### what's gaussian noise look like?

I am using Matlab function imnoise to add gaussian noise to one image. However, it seems that adjacent samples of the noise is correlated. I am using matlab code below to add noise. ...
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### How one can perform a noise free first order derivation in discrete domain?

I need to have a noise-free first order derivation. Now I am using a simple (x(n)-x(n-1))/Ts. It is super-sensitive to noises. Do we have a noise-free or noise-reduced first order differentiation ...
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### Predict the maximum power of a signal in the presence of noise

My question relates to predicting the power of a signal in the presence of noise. The signals I am analysing are discrete quasi-periodic signals (jittered sine waves basically). If I do a spectral ...
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### How can I duplicate this type of image?

I'm very new to the idea of signal processing, could someone point me in the direction of of a program to toy with images, below is a link to 2 taken a split second apart that showed up on my Amazon ...
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### What does pre-emphasis $\alpha=1$ will do to a signal?

I am trying to understand pre-emphasis equation. $$y[n]=x[n]-\alpha x[n-1]$$ Where $\alpha = 0.95$. My question is what does it mean if $\alpha = 1$?
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### What is the difference between photon shot noise and salt and pepper noise?

I am currently working on an application which deals with the restoration of fluorescent beads examined using widefield microscopy. There are two major sources of noises that are being encountered in ...
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### Valid non stationary non parametric white noise tests for non strick stationary time series

I could not find a question where testing for white noise for non strick stationary non parametric time series is adressed. Traditionally testing for white noise is done via multiple tests for the ...
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### how do i calsulate SNR of a noisy signal without having the noise?

i want to calculate the SNR value of a speech signal in matlab having only the clean and the noisy one and not the noise.what should i do?
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### Noise cancellation for known sources

Creating a noise cancelling earphones that cancel/suppress speech is a huge challenge , maybe even impossible. But what happens if we change the goals a bit: We need to cancel the ...
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### 3dB and 6dB Per Octave Rolloff Digital Filters / Generating Pink and Brown Noise

So I would like to have a design method for filters with 3dB and 6dB per octave roll off -- for generating pink and brown noise respectively. I know the following 'pinking' filters exist: Filter to ...
Given the system defined in the following figure: We have a system $G \left( f \right)$ which is unknown yet can be defined by ${N}_{p}$ poles and ${N}_{z}$ zeros. The signal \$ x \left( t ...