# Questions tagged [signal-processing]

Numerical analysis of a digitized signal

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7answers
34k views

### Features for time series classification

I consider the problem of (multiclass) classification based on time series of variable length $T$, that is, to find a function f(X_T) = y \in [1..K]\\ \text{for } X_T = (x_1, \dots, x_T)\\ \text{...
3answers
11k views

### Application of wavelets to time-series-based anomaly detection algorithms

I've been beginning to work my way through Statistical Data Mining Tutorials by Andrew Moore (highly recommended for anyone else first venturing into this field). I started by reading this extremely ...
1answer
22k views

### How can I align/synchronize two signals?

I'm doing some research but have come stuck at the analysis stage (should've paid more attention to my stats lectures). I've collected two simultaneous signals: flow rate integrated for volume and ...
4answers
10k 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 ...
1answer
971 views

### Dimensionality reduction of multiple signals using Fourier transform

I have $N$ recorded signals, $x$, each of which have been sampled 672 times across a time period of a week (= 15 min intervals). I will denote $x_{ij}$ as the $j$th sample for the $i$th recorded ...
0answers
65 views

### Getting rid of spikes in sample data [duplicate]

Possible Duplicate: Simple algorithm for online outlier detection of a generic time series How could I get rid of sparky data in a descrete data set, but in a "smoother out" manner? Take for ...
3answers
4k views

### Series dimensionality reduction for classification Input

I am looking to construct a predictive model where the outcome variable is binary and the input is time series. To make it more concrete, the model will predict if a customer churns (left the company; ...
2answers
3k views

### What is the difference between functional data analysis and high dimensional data analysis

There are a lot of references in the statistic literature to "functional data" (i.e. data that are curves), and in parallel, to "high dimensional data" (i.e. when data are high dimensional vectors). ...
1answer
18k views

### How should I normalize my accelerometer sensor data?

I'm working with a large set of accelerometer data collected with multiple sensors worn by many subjects. Unfortunately, nobody here seems to know the technical specifications of the devices and I don'...
2answers
30k views

### How to calculate the signal-to-noise ratio (SNR) in an image?

I am working with an image X, I apply the "adaptive median filter" in it and I get the image Y. I'd like to measure the SNR in both in order to evaluate the quantity of noise deleted. I know the ...
1answer
1k views

### Trend Analysis of feature importance over time in R

I'm running an experiment on a Streaming Classification Model (an Online Random Forest) that I've created. If that is a completely foreign concept to you here is a presentation I did on it recently: ...
2answers
2k views

### Testing significance of cross-correlated series

I want to prove that, overall, signal B is correlated to signal A. I was thinking of using cross-correlation (in R) to measure this. Essentially I have two kinds of signals: signal A is a series of ...
0answers
94 views

### Detect different fonts of audio from a single audio source

My code uses Google Voice API, to detect what one person said. For example, if I say one, two, three on my microphone the Google's API returns to me ...
2answers
2k views

### Regression with repeated measures in Matlab

Is there a way to perform multiple logistic regression on repeated measures data using Matlab? I have a data set containing a daily measurement recorded from 20 participants for 60 days. I am ...
1answer
665 views

### prediction on short time series with seasonality and data correlations

I have, say, 5 weeks of data standing for daily income of a company and I want to predict the next income. Obviously, there is a seasonality in data - every day is "seasonal" with the same day of the ...
2answers
2k views

### Predictions for random walk in ARIMA model

Below I'm showing just a small subset of a larger set of measurements of a process that I'm using to in turn predict something else. The part of the process that is my signal of interest is the ...
0answers
146 views

### How to improve estimation of a deconvolved density

I have the following problem: Y = X + e with Y = Total reaction time (noisy signal) X = selection time (signal) e = discrimination time (noise) I am interestend in the distribution for X and ...
0answers
103 views

### Detecting the period of a signal with a length of only a few periods [duplicate]

Possible Duplicate: Fourier data with non-integer periods, correcting for phase bias I have a not perfectly but quit periodic signal, with a length of only a few periods. What methods are ...
0answers
13 views

### Encoding a time series with varying time differences as an image

There are methods to encode a time series into an 'image' i.e a matrix of scalar values. Some methods include recurrence plots, gramian angular field and markov transition field. Most methods assume ...
1answer
305 views

### Test for fractional Brownian motion in Matlab

Is there a test in Matlab if a time series satisfies properties of being a fractional Brownian motion?