Questions tagged [denoising]

Denoising is a collection of techniques to remove unwanted noise from a signal. Typically this is done by filtering, but a variety of other techniques is available. Often combinations are used in sequence to optimize the denoising.

Filter by
Sorted by
Tagged with
1 vote
1 answer
35 views

understand short time fourier transform

I am reading this paper for signal denoising. In the paper, the authors says The core concept in this paper is to compute a regression between a noisy signal frame and a clean signal frame in the ...
user avatar
  • 135
5 votes
2 answers
94 views

Can the deconvolution Wiener filter reduce noise without having a blurred image?

I am trying to denoise many several noises with several filters for a research i have, i found a deconvolution Wiener filter made by "mr.tranleanh" on Github, as you can see here . what I ...
user avatar
  • 53
0 votes
0 answers
35 views

FFT denoising vs low pass filter

Say I have a noisy signal in which I want to denoise. There's two methods I'm considering FFT denoising, where I take the FFT of the signal and then threshold somewhere, attenuate all the frequencies ...
user avatar
5 votes
1 answer
77 views

Denoising a Grayscale Image Using Random Matrix Theory (RMT)

I am applying RMT on grayscale images. Basically for any matrix, it consists of two parts: one is pure noise and other is information. Now, to distinguish noise from information, RMT comes handy. We ...
user avatar
  • 51
-1 votes
1 answer
33 views

Why NMSE is the same as output SNR but with an opposite sign?

I am doing denoising on signal, and as performance measures Normalized Mean Squared Error (NMSE) and output-SNR between original/clean and denoised signals are used. However, for several cases the ...
user avatar
  • 1
6 votes
2 answers
131 views

The Effect of Spatial or Temporal Averaging on Noise Properties

I generate two noise images using MATLAB's function imnoise(). If I average the two noise images, the resultant image looks like the original noise image but only ...
user avatar
2 votes
1 answer
81 views

Hankel Matrix SVD Denoising

I have performed Hankel Matrix Singular Value Decomposition de-noising to smooth out my univariate time series. It is the close price of EUR/USD exchange rate. Here is a picture: The problem I have is ...
user avatar
0 votes
0 answers
37 views

Removing the Dot-Patterns Like Noise

I am dealing with an image restoration problem with noisy measurement. I use the classical total variation norm to remove the noise, specifically, the TV-$L_2$ problem. I used the famous Lena image ...
user avatar
5 votes
1 answer
94 views

Solving a Weighted Basis Pursuit Denoising Problem (BPDN) with MATLAB / CVX

Following up from an answer by @Royi on adding weights to BPDN problem , I would like to use CVX to test this approach. How can we formulate in CVX the regularized LS L1 norm with weights given by a ...
user avatar
  • 586
1 vote
1 answer
68 views

Does BM3D really need the noise power spectrum beforehand?

I'm at the moment trying to implement a neural network which uses BM3D as a preprocessing step. The problem is, when using the python implementation of BM3D from the paper Collaborative Filtering of ...
user avatar
1 vote
1 answer
84 views

How to remove heartbeat signal from blood pressure signal?

I am working on a medical engineering project that involves processing signals received from a human body. We use a sensor to record the blood pressure, $B(t)$. However, if you put your finger on many ...
user avatar
1 vote
1 answer
95 views

How to predict the final noise after adding two or more noisy discrete signals?

Is it possible to accurately predict the noise level if we add two or more noisy signals. For the sake of simplicity, let us say, the noise is independent and Gaussian. Suppose we wish to add signals $...
user avatar
  • 498
1 vote
0 answers
45 views

Remove Noise from Discrete Signal with given Noise Model

I am interested in finding the true signal $p \in \mathbb{R}^D$ of an observed discrete signal $t \in \mathbb{Z}_{+}^D$. I know that each observed $t_{i}$ with $1 \leq i \leq D$ is the result of a ...
user avatar
  • 223
6 votes
1 answer
121 views

Solve Efficiently the 1D Total Variation Regularized Least Squares Problem (Denoising / Deblurring)

How to solve a 1D Least Squares with Total Variation Regularization? I know gradient based methods, I wonder how much faster / efficient I can get.
user avatar
  • 640
4 votes
1 answer
53 views

How to Remove Temporal and Fixed Pattern Noise and Apply Tone Mapping?

I have a video, whose frames I have extracted and require to work with. 16 bits and grayscale images. My task is to improve the quality of the images, by removing the noise + adding tone mapping and ...
user avatar
-1 votes
1 answer
46 views

Verifying if noise is gaussian in non-time series data

I'm trying to figure out if the noise in my experiments is gaussian or not. I don't have time series data. I first configure my system and then run some software application's and measure the average ...
user avatar
0 votes
0 answers
17 views

Directions on how to estimate the additive intensity bias

I have been reading this paper on how to estimate the additive intensity bias from an image, and I want to test it and write an algorithm for it. However, I can't seem to understand how to write the ...
user avatar
7 votes
2 answers
424 views

How to Solve Image Denoising with Total Variation Prior Using ADMM?

I was looking at some articles or Wikipedia on denoising images using the Total Variation norm. The setup is the Rudin Osher Fatemi (ROF) scheme, and the corresponding equation is: $$ F(u)=\int_{\...
user avatar
  • 257
0 votes
1 answer
43 views

Digital Filters

If I want to remove the baseline drift in my ECG signal, which digital filter should be used without distortion and shift in my filtered output? What are the necessary things I have to look for the ...
user avatar
0 votes
2 answers
79 views

GPS | Retain Signal Tracking after Noise Bound

I have an IF data, 2 seconds signal sample from only one GPS satellite, I know the PRN number of the satellite. ...
user avatar
0 votes
1 answer
94 views

How to filter sudden spikes and baseline changes in microphone signal?

The orange is a signal I recorded, the blue - my first restoration attempt, after which I decided to ask. The signal is audible, however there are 2 types of defects 1) baseline changes 2) sudden ...
user avatar
  • 101
0 votes
0 answers
350 views

Pre-Processing Wi-Fi Channel State Information (CSI) Data

I was successfully able to collect some CSI data using the existing tool(s) on GitHub (https://github.com/StevenMHernandez/ESP32-CSI-Tool). The CSI data is a pair of imaginary and real number which ...
user avatar
1 vote
1 answer
67 views

Adding noise to real MRI data

I designed an algorithm for MRI data denoising which has good properties under heavy Rician noise (sigma is greater than 80). The method was tested on some phantoms and Rician noise generators. Now I ...
user avatar
  • 27
0 votes
0 answers
28 views

Deconvolution of sidelobes in a point spread function?

It seems that most deconvolution algorithms mainly handle the main lobe of a point spread function (PSF) and assume that sidelobes can be safely neglected. For a direct algorithm trying to perform a ...
user avatar
  • 101
2 votes
1 answer
43 views

Image noise reduction

I have an image of a cross-section of soil where the main object of interest are the plant roots. I would like to segment or extract the roots from the background noise of the soil itself and other ...
user avatar
4 votes
2 answers
119 views

Is it possible to remove the non-random noise in the signal by averaging?

Ex: We're measuring vibration Frequency response of a structure, and at the same time there is a constant source of vibration (noise) from a pump. The pump is exciting the structure by sinusoid ...
user avatar
  • 41
6 votes
2 answers
429 views

What is the advantage of Wiener filter for noise reduction of a 1D signal?

I have a 1D signal, acquired by an accelerator sensor that measure the vibration of a structure. What is the advantage of using a Wiener filter for noise reduction compared to the other (more classic) ...
user avatar
  • 363
0 votes
1 answer
37 views

Time averaging denoising signal

I would like to use time averaging technique for denoising vibration signal, using the below function, how do we choose the appropriate parameters D and N for optimal denoising ! ...
user avatar
  • 35
1 vote
0 answers
27 views

Noise removal where gains are >1

I am currently working on some noise removal algorithms and have come across what seems to be an oversight in the design of some of these algorithms. Two of the algorithms I am looking at use the PSD ...
user avatar
  • 11
1 vote
0 answers
48 views

Logarithmic Amplitude Spectral Subtraction

I'm diving into audio processing and I'm trying to wrap my head around spectral subtraction. I learned there are different approaches do it based on power, magnitude, oversubtraction. My task is to ...
user avatar
  • 9
1 vote
2 answers
74 views

What is the best estimate of a signal given multiple noisy realisations

I assume that the noise corrupting the sought-for signal is [Edit: Gaussian] white noise of zero mean and unknown variance. Is the optimal solution simply the mean over the realisations (the ensemble ...
user avatar
  • 11
3 votes
2 answers
75 views

Help with denoising signal and periodogram analysis resources

This is a cross posting from the crossvalidated stack exchange as I thought this may be a better forum to ask. I have a dataset consisting of respiratory time series signals of different lengths ...
user avatar
  • 141
5 votes
1 answer
72 views

What Are Intuitive Explanations for Shrinkage in the Context of Image Denoising?

I have occasionally come upon the term "shrinkage", mostly in the context of denoising methods. My rough understanding is that it refers to the part where the real distribution might not be ...
user avatar
  • 193
1 vote
1 answer
85 views

Understanding noise removal method using wavelets

I am trying to understand how wavelet transform can be used to denoise a time series or signal and how to plot the scalogram image. My signal has a lot of fluctuations and as such I am finding it ...
user avatar
  • 291
2 votes
1 answer
39 views

Enhancement by adaptive wavelet shrinkage denoising

I was wondering does anyone know any programming library or a way that can help me implement this algorithm.
user avatar
5 votes
3 answers
113 views

How to denoise a video stream from poor CCTV lighting

I have grainy CCTV footage that will need some amount of clean up. I request for ideas on the best way to clean out the noise. I am attaching a frame extracted from the video here for hints on the ...
user avatar
1 vote
0 answers
32 views

What are the wavelet packet functions and how are they different from the wavelet and scaling functions?

I understand that in the decomposition process, wavelet and scaling functions are used to split the signal to approximation and detail coefficients. Most of the time I saw the wavelet and scaling ...
user avatar
  • 61
5 votes
1 answer
95 views

Removing Gaussian Noise from a Signal to Get Minimum Value

I have a signal that has a minimum value that I'm trying to read. The issue I'm having is that the signal is spread out by gaussian noise. I have the signal at a lot of timesteps (and expect the ...
user avatar
  • 153
1 vote
0 answers
301 views

Implementation of Cepstrum in Python

Actually I want to denoise a signal. I know how can I implement FFT in python to denoise it. This is the implementation which I use(From this Kaggle notebook): But I don't know : How can I use ...
user avatar
7 votes
1 answer
100 views

Recommended Resources / Literature Search Terms for a Solutions to a Specific Kind of Multi Harmonic Signal Structure

Hopefully this isn't considered too off-topic. I'm working in industry these days and came up with a solution to a signal processing problem we'd been facing. I'd like to get a sense as to whether ...
user avatar
1 vote
0 answers
38 views

Why should wavelet re-synthesis produce an output when the main component is suppressed and what does this mean for denoising?

I understand that aliasing occurs in DWPT if the wavelet used is of low order since the "filters" are not perfect and the combination of down sampling and overlapping between bands causes ...
user avatar
  • 61
6 votes
1 answer
233 views

A Simple Algorithm to Filter / Smooth / Denoise a Noisy Staircase Graph

Is there a way to remove the noise and smooth the graph into a staircase graph.
user avatar
  • 63
0 votes
0 answers
25 views

Discrete wavelet center frequency

I am understanding that mother wavelets have a center frequency. Wavelets are limited in duration and oscillate then decay, so the center frequency is the mid pulse of the wavelet or so. But my ...
user avatar
  • 61
1 vote
0 answers
17 views

How well can discrete wavelet packet transform reduce noises that are similar to the input signal in the same frequency band?

If I had 50Hz noise coming from power line, and signals in the same frequency range (EEG for example 0.1Hz to 100Hz). If my sampling frequency is 30kHz but I downsample my signal to 937kHz and use the ...
user avatar
  • 61
1 vote
1 answer
59 views

Eroding noisy borders of polygons in an image

I am new to image processing, and this is the task at hand. I have a mask image of shape 500x500x1 that contains polygons. These polygons (=vector data: common term in remote sensing and GIS) are ...
user avatar
1 vote
0 answers
38 views

Best way to measure effectiveness of discrete wavelet denoising?

I am using matlab wavelet toolbox to denoise physiological signals, I am plotting the denoised signal on top of the original noisy signal and making sure spikes were not removed as a measure of ...
user avatar
  • 61
0 votes
1 answer
69 views

Automatic detection of noise-only segments in audio

This is my first question for this community. My connection to DSP comes via machine learning/deep learning, and I am working in the Python ecosystem. As a preprocessing step to audio classification, ...
user avatar
  • 101
1 vote
2 answers
140 views

Can discrete wavelet transform for denoising purposes be implemented in real time? [closed]

I have been researching effective algorithms for denoising biomedical signals (non-stationary) that can be implemented in real time either using FPGA or DSP. I can across many suggestions for ...
user avatar
  • 61
2 votes
1 answer
36 views

denoising floor function

Suppose that $y(t) = \lfloor x(t) + \epsilon(t) \rfloor$, where $\epsilon(t)$ is zero mean, independent noise. Is there any techniques on recovering $x(t)$ from $y(t)$?
user avatar
0 votes
3 answers
938 views

Help with Audio Signal noise removing using FFT and IFFT in Matlab

I dont understand why my modified fft of a audio signal returns complex values after ifft. I modified my signal by zeroing out all the unnecessary freq. FFT: Fast fourier transfrom IFFT: Inverse ...
user avatar