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

learn more… | top users | synonyms

0
votes
0answers
14 views

Simulate noise on the x axis for raw time-of-flight mass spectrometry signals

I am analyzing raw mass spectra produced by a time-of-flight mass spectrometer. These spectra are 2 dimensional signals that consist in intensity values with respect to mass/charge values. Here is an ...
0
votes
2answers
44 views

Noise removal from audio using FFT/Spectral editing

I have a noisy recording with some letters spoken out loud. I've noticed that the noise is easily recognizable when looking at a spectrogram of the audio. Is there anyway to set a power/frequency ...
1
vote
1answer
114 views

What do we espect Likelihood function used for?

In my understanding, I let make a example. For example, you can see in the following picture. Consequently, We want to find ^sigma. and We have already known the observation data(which is random ...
0
votes
2answers
24 views

FIR Filter matlab command

i'm trying to understand the fir1 filter but i still don't get it. For example here i got an audio signal that i consider noise, i'm passing it through a low pass filter. ...
0
votes
0answers
21 views

time domain non stationary time series individual colored noise identification algorithm

One of the methods for identification of modulated colored (stationary) noises is that of lag 1 autocorrelation power law noise identification algorithm. This method can determine the dominant noise ...
0
votes
2answers
52 views

adding noise to a signal

I have an audio file. I took an extract of the file called variable "CALL", and I took another extract from the file which is just filled with background noise, called "BACKGROUND". Using matlab, I ...
0
votes
1answer
54 views

Matlab: if given nothing but an audio file, how do I modify it to produce incrementally lower signal to noise ratios?

I have an audio file with a high sampling rate of 250khz. It contains animal noises. I've built a program which counts all the animal noises. However, I want to find out how robust the program is and ...
2
votes
2answers
55 views

How do can we cancel out noises while listening voice on headphones?

It's a common problem that while talking with the another person on Smartphones with the help of regular headphones,we get very annoying sounds at background . The opposite person's voice gets mixed ...
0
votes
1answer
14 views

Concepts Surrounding First Two Samples in Difference Equation

I'm attempting to construct a difference equation in matlab for the function u(n) and find the auto-correlation matrix R. I'm following the technique as is defined by my text below: The system I'm ...
0
votes
2answers
40 views

how to estimate the noise of a signal?

please can someone help me to define a method that allows me to estimate the power of noise in any signal? the signal is received by usrp and the problem that it is variable all the time in the FM ...
1
vote
1answer
49 views

How to estimate the noise of an image?

I want to know how to estimate the noise of an image? Also is this represent the camera's noise? Does anyone know how to estimate the noise of an image or camera? Update: Especially, I want to ...
0
votes
0answers
20 views

How to estimate noise level and actual intensity of image from a noisy image?

The image I have is corrupted with random (natural) noise. So I would call it Gaussian noise. I am thinking of the following approaches for denoising: Mean filter Non-local means filter Averaging ...
0
votes
1answer
28 views

Can we decompose a correlated random variable into correlated plus uncorrelated?

Assume a random sequence $ Y_k = X_k \cdot H_k + W_k $ where $X_k$ is a deterministic quantity, $H_k$ is a correlated random sequence, $W_k$ is Additive White Gaussian random sequence. Can we ...
0
votes
0answers
7 views

use of recurrence quantification analysis for deterministic signal identification and classification

The recurrence quantification analysis (RQA) is a method of nonlinear data analysis which quantifies the number and duration of recurrences of a dynamical system presented by its state space ...
0
votes
0answers
35 views

Kalman filter - mathematical model for signal strength based tracking

I'm currently trying to wrap my head around Kalman filters. I've read some tutorials/introductions on this subject and am trying to apply it to a problem to get a better understanding of the mechanics ...
0
votes
0answers
24 views

Is it possible to calculate the variance of signal in real time implementation? [duplicate]

In communication system, when we received some signal which contain our message of known variance sigma_s which is corrupted in noise of unknown variance. If I need the variance of the signal in ...
0
votes
1answer
60 views

how to create synthetic $1/f$ noise? [duplicate]

I am writing an app to work with synthetic time series data from a physics experiment. In our experiments we always have $1/f$ noise in our time series, but I haven't been able to find code/packages ...
0
votes
2answers
17 views

Noise modeling and reduction in Video when we have just noisy video

We would like to send a video (sequence of images), we have limit bandwidth. If there is a lot of noise, the required bandwidth (bitrate) is needed to send the video+noise becomes high that is not ...
0
votes
1answer
45 views

1D filter for speed input and noisy position sensor

I was tasked with designing a filter to smooth out a translating table. The system, we command a speed and a desired position, and measure it with two noisy position sensors. The commanded speed is ...
0
votes
1answer
28 views

Notch filtering line noise outside of frequency band of interest

Practically speaking, if one is interested in a frequency band well-separated from the line noise (say, for example, the 10-20 Hz band, with 60 Hz line noise), would it be advisable to notch out this ...
0
votes
1answer
39 views

Diagonal vs non diagonal processing for audio denoising

I am going through a technique for audio denoising by block thresholding. Here is the paper: http://www.di.ens.fr/~mallat/papiers/AudioBlock.pdf According to the definition in the paper for ...
0
votes
1answer
35 views

Adaptive Digital Filter Block Diagram Question

I'm currently attempting to study up on adaptive digital filters. My book presents the diagram I've included below and I'm having trouble understanding conceptually what it's indicating. The problem ...
0
votes
3answers
80 views

How to remove heart beats interference from pectoralis major electromyogram?

I am using electromyography to detect activity on pectoralis major, however I found an interference from heart beats that is affecting my posterior analysis. The sampling rate is 2000 Hz, and the time ...
4
votes
1answer
77 views

How can noise be good?

It seems like (controlled) noise can sometimes be good: dithering in an image, or a softer sound in audio, or white noise alone. Here's a paper on noise improving detectability. My intuition also says ...
0
votes
1answer
27 views

What type of sensors have complex Gaussian noise?

What type of sensors have complex Gaussian noise? Do strain gauges also exhibit such noise?
2
votes
1answer
50 views

How to find out whether guassian or salt& pepper noise present in an image, Is there any algorithm

Is there any algorithm for identifying the noise in an image I have to identify whether the noise present in a mammogram image is guassian or salt& pepper.
9
votes
3answers
155 views

What is the type of noise in this image?

what reason could make the noise/effect in this image? Below is the original Thanks!
1
vote
1answer
66 views

Tinnitus Masking with broadband Noise

I have the problem of masking tinnitus. I have the following questions: Can broadband noise mask tone tinnitus, or any kind of tinnitus (such as narrowband, or chirp)? Assume an audiogram test has ...
1
vote
0answers
30 views

Can sample aliasing of strictly white noise lead to random walk (drift) in the sampled signal?

Aliasing of tones higher than the Nyquist frequency, and where the tone may have some degree of nonlinear distortion can appear as low frequency 'drift' or even near static bias in the sampled signal. ...
3
votes
3answers
217 views

Removing unwanted square-wave noise from a signal

I have a signal, s, given at the end of this message. I need to remove the square wave shape from it. The desired signal is actually very small and it has been contaminated by a strong square-shape ...
0
votes
1answer
35 views

Noise power transient at output of RC filter

Consider a simple first-order RC filter with AWGN input noise with single-sided density of No. We know the output noise power is No/(4RC). What is rarely noted is that this is true after steady-state ...
2
votes
1answer
50 views

Gaussian noise generator algorithm trouble

I stumbled upon the following algorithm for Gaussian noise generation and I just can't figure out how this is supposed to work at all. The algorithm is as follows: First of all: j = argmin_i (q_1 ...
1
vote
0answers
36 views

Generating Gaussian noise uncertainty?

How can I generate non-stationary Gaussian noise (noise uncertainty) using Matlab? where the noise power fluctuate between $(1+p)^{-1}$ to $(1+p)$ where $p$ is the uncertainty factor in dB. Best
0
votes
0answers
83 views

Removing background noise (sound) by attenuation below certain amplitude (loudness) in MATLAB

I have to write a MATLAB code that attenuates sound at low amplitudes to zero, in VoIP. Meaning I have to reduce low amplitude sound to zero E.G. while speaking I have some background noise (like the ...
2
votes
2answers
90 views

carrier frequency difference

Papers use wireless device-dependent radio-metrics as fingerprints. A radio-metric is a component of radio signal, amplitude, frequency and bandwidth. Each device creates a unique set of radio-metrics ...
0
votes
0answers
48 views

filter out an expected but not regular signal

I am stuck with a case where I need to get rid of a portion of sinusoidal signal that suddenly appears in my main signal (sine wave). my total signal will look like: $ s(n) = \begin{cases} ...
1
vote
1answer
92 views

Equalizing 1/f noise

I am recently acquiring data through ADC on signals ranging from 0.1 Hz to 50 KHz (Fs = 128 KHz). I noticed that apart from the white noise, I have something similar 1/f noise with a cutoff near 1 Hz. ...
4
votes
2answers
218 views

How to remove the noise without destroying the main edge?

I am working on a project. I want to segment a logo from a car and the picture's size is 3648*2432. The logo is selected by the red rectangle. I extracted this area and turn into gray level. The ...
1
vote
2answers
159 views

Fourier transform possible on non-rectangular part of an image

Dear Signal Processing readers, I want to introduce 'noise' into parts of images. Until now, I worked with rectangluar images for a similar purpose and did the following, using (inverse) Fourier ...
2
votes
2answers
129 views

Simulating noise in OFDM

I'd like to simulate a certain $E_s/N_0$ in a baseband OFDM MATLAB modem to generate SER curves. I randomize 50 QAM symbols with $N$ subcarriers each in frequency domain, add null frequencies (guard ...
2
votes
3answers
129 views

How to determine SNR from FFT of measured data?

I am doing impedance measurements, where I do a frequency sweep of a test current, and I measure the resulting voltage. Offline, I compute the FFTs of the voltage and current, and I want to make sure ...
0
votes
0answers
41 views

Estimate Image power spectrum of the noise

I want to implement Wiener filter. I have original image and image blured with linear motion. The one thing I am lack of(to implement it) is Noise power spectrum. I know that it is hard task. I've ...
7
votes
5answers
197 views

Improving Digitization by Adding White Noise Before Oversampling

I was reading a physics book and it said that when digitizing a signal white noise was added to improve the process. I don't understand how this works. Therefore my question is: When digitizing an ...
1
vote
3answers
94 views

Normalization purpose in signal processing

What is the purpose of normalizing the signal? If we have two signals on hand, how is it used when comparing these two signals?
1
vote
1answer
50 views

Frequency of a noisy signal with fixed width pulses

My electricity meter has a front panel LED which pulses in proportional to the current energy rate. The frequency changes but the pulse width is set at 250ms. Due to environmental conditions there's ...
0
votes
2answers
106 views

'A priori' and 'a posteriori' SNR

I am reading this paper about speech enhancement using a minimum mean square error short time spectral amplitude estimator for our speech enhancement project. Basically in the paper they mix a clean ...
0
votes
1answer
19 views

Expected value of coupled signals is zero

Suppose there are two vector signals, $u$ and $v$, which are functions of time. Given, $E[uv^T]=0$, what is the physical significance of this statement. For clarity, assume $u$ and $v$ are noises in a ...
0
votes
0answers
17 views

Noisy omni-directinoal UWB radar

I am working with an omni-directional UWB radar and need to make meaningful sense of the data to distinguish objects that could represent an obstacle. It is interfaced and giving me data, but I was ...
0
votes
1answer
139 views

Improving an auto-correlation based guitar pitch detector

I've seen many questions on this forum regarding pitch detection for musical instruments (commonly guitar), and spent a while reading through the answers to create a basic implementation of ...
2
votes
2answers
281 views

What is the rms value of a signal and how to use it

In some papers/books I found infos about a signal given as RMS value. What is the RMS value and what information does it contain? How can I compute it? Moreover, if they say that the signal is a ...