Questions tagged [signal-processing]

Numerical analysis of a digitized signal

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14 views

How to get audio stream from internal sound card and beat match using reinforcement learning

I'm working on a DJ project to play different tracks and mix between them. The approach I am following is that of tokui to use reinforcement learning to speed up or slow down a track so that tracks ...
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4 views

Compressed Sensing with a Non-Invertible Sparsifying Transform

In "The Restricted Isometry Property and Its Implications for Compressed Sensing" (https://statweb.stanford.edu/~candes/papers/RIP.pdf), Candes describes the Noisy Recovery problem to be as follows (...
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9 views

Signal to noise ratio for structural equation models

Consider the linear structural equation model with known $\beta$ as $$ SEM \quad X_k = \sum_{j=1}^{p}\beta_{jk}X_j + \epsilon_k$$ where $X_k$ is a random variable. I construct a data matrix $D_{m \...
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6 views

Defining error safety in cross correlation of two binary signals

I want to cross correlate two binary signals, where one is currupted by noise and shifted by a timeconstant tau, but has the same bit pattern (so basically an auto correlation). Similiar to case 2 in ...
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10 views

An Interesting Model with Unknown Orthogonal Design Matrix

Consider a linear mixed model, $$\mathbf{y}_{ij}=\mathbf{\Gamma}\mathbf{\mu}+\mathbf{z}_i+\mathbf{e}_{ij}, ~~ ~~i=1,\ldots,m,~~j=1,\ldots,n_i, $$ where $\mathbf{y}_{ij}$ are $k\times 1$ observation ...
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30 views

Estimation of NegEntropy

I am trying to evaluate the different ICA algorithms. To do that, one of the measure which I use, is to estimate the non-gaussianity using NegEntropy. I am trying to find a formula/function which can ...
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21 views

How to test whether event A affects the frequency at which event B occurs

I conducted an experiment in which I measured the occurrence of some event A over time. I then intervened in the system, periodically introducing event B. I hypothesise that event B affects the ...
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23 views

Terminology: Is DTW considered to be machine learning or signal processing?

The DTW Wikipedia article puts this method in the category "Machine learning algorithms". On the other hand, the famous paper "Dynamic Programming Algorithm Optimization for Spoken Word Recognition" ...
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6 views

Speaker normalization of features before model training

I am building a model using a supervised machine learning based on features I extract from speech signals. The features include MFCC, auto correlation and energy derivatives. According to this paper,...
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5k views

Is it a good idea to use CNN to classify 1D signal?

I am working on the sleep stage classification. I read some research articles about this topic many of them used SVM or ensemble method. Is it a good idea to use convolutional neural network to ...
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51 views

Strange accuracy graph

I was training my NN when I found out something I CAN NOT understand. My net is a bilstmLayer and a softmaxLayer layer with 10 MaxEpochs and 150 MiniBatchSize. I want to classify 4 different type of ...
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22 views

Variances add, and therefore subtract?

Variances add, so va + vb = vc. If I know what va and vc are, can I estimate vb by vb = vc - va ? More specifically, I have a noisy statistical time series which consists of the pure signal plus ...
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25 views

Constructing signal vector of EWMA

I have daily stock returns related to sectors. At the end of each month I want to construct a vector of signals using the past data with different methods over different moving windows like EWMA over ...
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12 views

Signal processing of data which fluctuates

I have a system which measures weight of plants. The weight is measured through four weight cells on a "plate". A spray is applied for 3 seconds from under the plate, and waits 60 seconds for the ...
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1answer
19 views

How to deal with varying number of intervals and hence varying number of features dividing an audio signal while classifying these audio signals?

I've $2000$ audio signals, each divided into a number of time intervals/time frames of $50$ miliseconds (ms) and these signals have overlaps for $25$ ms. Now, the audio signals being of different time ...
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19 views

Clearing out errors from a data set

Sorry for the vagueness of the title, I am having a hard time even coming up with sort of problem I am facing (if there is a specific name for it....) In a nutshell, I have a time series of points, ...
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22 views

Recovering a distribution after Gaussian noise is added

I have a large dataset (400k rows) in which I suspect the data has been obfuscated by the addition of a Gaussian distribution. My guess is that some of the data had categorical variables (based on the ...
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12 views

Demonstrate the mean of the sample variance

Let's suposse I have a vector of elements $x(n) = \{x(1), x(2), \cdots ,x(N-1)\}$ from a random process X of mean $\mu_x$ and variance $\sigma_x^2$. I want to see if I can stimate the mean and ...
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1answer
15 views

How to use GMMs for acoustic signal classification?

There are a number of applications of the Gaussian Mixture Model (GMMs) to acoustics/audio data for the purposes of classification; ex paper1 and ex paper2. GMMs ...
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7 views

Degree of freedom of estimated sotuioin to the total variation problem from the ADMM algorithm

The study of the total variation problem is to solve the following problem: $$ \text{minimize} ~ \frac{1}{2}||x - b||_2^2 + \lambda * \sum_i^N |x_{i+1} - x_i| $$ where $x$ is the unknown, $b$ in $R^...
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19 views

Find roots of regression function

Physical problem: Signal data comes from several sensors (e.g. 4) and there is empirical knowledge, that data of one of them (e.g. "productivity") depends on other data. Signals of other sensors could ...
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67 views

Detection of music note sequence in audio signal

I have an audio signal which contains the combination of different western music notes(I know this combination in advance) and I want to identify the sequence of the music notes present in it. For ...
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33 views

What is matching pursuit algorithm?

I would like to know What is matching pursuit algorithm? I did search via different sources but no understandable explanation is available! Can anyone help with this, please?
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25 views

Roughness of time series or physical measurements

I am facing regularly the same issue regarding the stability of my physical measurements. How stable is my equipment? How noisy is my signal? For example, I apply a current on a resistor and want to ...
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30 views

Additional Property of Singular Value Decomposition

I am new to SVD so forgive me if the question is trivial. Following is my question. If I have two sets of linear equations, Y1 = T1.X Y2 = T2.X where T1 and T2 are mxn rectangular matrices. Now let'...
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23 views

Significance testing of signal-to-noise ratio

I have three 18-second, 32-channel resting state EEG time series sampled at 500 Hz using dry EEG electrodes (condition 1) and three more 18-second, 32-channel resting state EEGs also sampled at 500 Hz ...
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Matching Pursuit & Boosting: Exponential Convergence?

In the paper by Bühlmann BOOSTING FOR HIGH-DIMENSIONAL LINEAR MODELS, he introduces an algorithm, called componentwise linear least squares, and relates it to the Matching Pursuit algorithm by Mallat &...
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1answer
61 views

Eigenvalue decomposition/SVD and the filtering perspective

I have been studying the SVD algorithm recently and I can understand how it might be used for compression but I am trying to figure out if there is a perspective of SVD where it can be seen as a low ...
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17 views

Estimate Convolution Filter Formula from Noisy Input and Output

When I learned signal processing, I learned how to calculate the output with given input and given convolution filter. However, if now I have the noisy input and output, assuming the system is linear ...
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18 views

Is there a concept of weakly periodic in stats? If so, what is it called?

Ok, say we have a signal that reoccurs within every T+x time where T is a constant and x is a random number small in size compared to T. We know that a function is actually periodic if F(x) = F(x+T), ...
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62 views

Comparing PCA representations between low-pass and high-pass filtered time-series data

I am currently trying to reduce the number of variables I input into a vector autoregressive (VAR) model. For those that don't already know, VAR models are used on time-series data. My primary concern ...
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Developing algortihm/model to identify thin linear features in aerial imagery [closed]

I am exploring the possibility of identifying fencelines from NAIP aerial imagery (GSD = 0.6m). I have tried some basic processing in OpenCV using canny edge detection that was detailed in a question ...
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1answer
40 views

Verifying Time Warp

Time warp has been widely assumed in domain of speech processing. If $Xw(t)$ represents a time warped version of $X(t)$, then $Xw(t) = X(t-w(t))$ where $w(t)$ is an arbitrary function with a banded ...
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12 views

How to find the frequency at which loudness levels are varying the most?

I have a dataset consisting of loudness level readings of the sound produced at a national highway, taken on a per second basis at different frequencies(20Hz to 10,000Hz). I have to find out the ...
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1answer
71 views

Does mutual information capture interactions?

Suppose I have a response $Y$ and two features, $X$ and $Z$. Individually the features are not very predictive but their interaction is strongly predictive. Something like $$Y = 0.5X + 0.5Z + 20XZ + \...
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1answer
99 views

Filtering out bursts with a consistent range from a time series

I have time series of bursts that look like this: … and zoomed in: Now, there are also spurious bursts (which I call noise) in the data, which look like this: … and zoomed in: As you can see, the ...
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18 views

When doing feature selection based on mutual information, should it be normalized?

Are any kind of normalizations useful when using mutual information to select features? The Wikipedia page has a few variants but they don't seem helpful. The entropy of the response is a constant ...
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3answers
332 views

Usage of Hidden Markov Models

I have a set of questions regarding how HMMs are used. Context: there is a stream of real numbers or real number vectors (e.g. data from a phone accelerometer) and the goal is to detect that an ...
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88 views

covariance matrix vs correlation matrix for multiple signal analysis

I'm dealing with a set of +100 input signals, and one output. I want to explore how each of the signals affects the output. Should I focus on covariance matrix, or correlation matrix, and why? I ...
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1answer
44 views

Is (1 - Coherence) a metric, at a given frequency?

I'm performing some signal analysis and was using coherence (magnitude-squared coherence) to inference signals similarity. Now, I need to extend the framework by introducing a metric. I was wondering,...
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135 views

What is the differennce between invariance to translation, covariance to translation and equivariance to translation?

I get stuck at understanding the difference between invariance to translation, covariance to translation and equivariance to translation in the context of of convolutional neural network. What does ...
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87 views

What features are suitable when predicting user preferences for songs?

I have a data set consisting of 1240 audio files (30 seconds each) and a file like this (two first rows): u v decision 1 323 0 12 9 1 ...
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2answers
138 views

Features for multi-channel time series classification

I am quite confused about extracting features of the multichannel signals and wonder if anyone can help me out. I want to get a feature set where feature is related to time, but I found the only way ...
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66 views

Is Spearman's rank and RMS error an appropriate measure of similarity between two signals?

I am working on a project comparing the accuracy of two imaging techniques to measure displacement. I have attached a graph comparing the displacement measured by both techniques over time. I am ...
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1answer
291 views

Time Series Classification with Varying Sampling Frequency

I'm new to signal processing and am wondering how to deal with a time-series classification problem when I have unequally spaced data. Skimming through recent literature, including The great time ...
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1answer
256 views

How to combine multiple signal data in my ML model?

I'm doing a task where I need to work with healthcare data from a few different sources. For example, one is an audio signal recording while another is biometric signal reading such as ECG. Both of ...
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27 views

Time alignment of two signal with same length

I have found information about similar topics, but wasn´t useful for me. I have the next 2 signals registered by a laser profilometer. As can be seen in the picture the signals are almost equals but ...
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19 views

Clustering of an image sequence of a moving object

I have a set of 100 images of a man moving on the street. I remove the background and try to cluster the man using dbscan in each image seperately. Instead of getting one cluster (for the man), I get ...
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1answer
289 views

Intervention/Level Shift detection

I don't really know if this problem can be considered as an intervention detection/analysis problem. The data shown below is actually a sensor signal collected from an air booster. The air booster has ...
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108 views

How can I get the cumulant expression from the recursive relation between cumulant and moment?

I am reading some paper about high-order statistics https://link.springer.com/article/10.1007%2Fs11004-009-9258-9?LI=true. The paper gives two recursive expressions relating the multivariate cumulants ...