Descriptive Statistics

Peaks, RMS level, peak-to-peak amplitude, crest factor, dynamic time warping, CUSUM control chart, edit distance

Use findpeaks to locate the local maxima of a signal and sort the peaks by height, width, or prominence. Determine the crest factor of a signal using the peak2rms function and compute common descriptive statistics like maxima, minima, standard deviations, and RMS levels. Search for signals of interest in larger data sets and align signals in time. Locate points where a signal changes abruptly or drifts beyond a target range. Label signals for analysis or machine and deep learning applications.

Applications

Signal Analyzer	Visualize and compare multiple signals and spectra
Signal Labeler	Label signal attributes, regions, and points of interest, and extract features (depuis R2019a)

Fonctions

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Statistics

`cummax`	Cumulative maximum
`cummin`	Cumulative minimum
`envelope`	Signal envelope
`max`	Maximum elements of array
`mean`	Average or mean value of array
`meanfreq`	Mean frequency
`medfreq`	Median frequency
`median`	Median value of array
`min`	Minimum elements of array
`movmad`	Moving median absolute deviation
`movmedian`	Moving median
`peak2peak`	Maximum-to-minimum difference
`peak2rms`	Peak-magnitude-to-RMS ratio
`rssq`	Root-sum-of-squares level
`seqperiod`	Compute period of sequence
`std`	Standard deviation
`var`	Variance

Feature Extraction

`alignsignals`	Align two signals by delaying earliest signal (depuis R2019a)
`cusum`	Detect small changes in mean using cumulative sum
`dtw`	Distance between signals using dynamic time warping
`edr`	Edit distance on real signals
`findchangepts`	Find abrupt changes in signal
`finddelay`	Estimate delay(s) between signals
`findpeaks`	Find local maxima
`findsignal`	Find signal location using similarity search
`signalFrequencyFeatureExtractor`	Streamline signal frequency feature extraction (depuis R2021b)
`signalTimeFeatureExtractor`	Streamline signal time feature extraction (depuis R2021a)
`zerocrossrate`	Zero-crossing rate (depuis R2021b)

Signal Labeling

`labeledSignalSet`	Create labeled signal set
`signalLabelDefinition`	Create signal label definition
`countlabels`	Count number of unique labels (depuis R2021a)
`filenames2labels`	Get list of labels from filenames (depuis R2022b)
`folders2labels`	Get list of labels from folder names (depuis R2021a)
`splitlabels`	Find indices to split labels according to specified proportions (depuis R2021a)
`signalMask`	Modify and convert signal masks and extract signal regions of interest (depuis R2020b)
`binmask2sigroi`	Convert binary mask to matrix of ROI limits (depuis R2020b)
`extendsigroi`	Extend signal regions of interest to left and right (depuis R2020b)
`extractsigroi`	Extract signal regions of interest (depuis R2020b)
`mergesigroi`	Merge signal regions of interest (depuis R2020b)
`removesigroi`	Remove signal regions of interest (depuis R2020b)
`shortensigroi`	Shorten signal regions of interest from left and right (depuis R2020b)
`sigroi2binmask`	Convert matrix of ROI limits to binary mask (depuis R2020b)
`sigrangebinmask`	Label signal samples with values within a specified range (depuis R2023a)

Rubriques

RMS Value of Periodic Waveforms
Find the root mean square value of a sine wave, a square wave, and a rectangular pulse train.
Find Peaks in Data
Locate the local maxima in a set of data and determine if those peaks occur periodically.
Prominence
The prominence of a peak measures how much the peak stands out due to its intrinsic height and its location relative to other peaks.
Human Activity Recognition Simulink Model for Smartphone Deployment (Statistics and Machine Learning Toolbox)
Generate code from a classification Simulink^® model prepared for deployment to a smartphone.
Choose an App to Label Ground Truth Data
Decide which app to use to label ground truth data: Image Labeler, Video Labeler, Ground Truth Labeler, Lidar Labeler, Signal Labeler, or Medical Image Labeler.

Exemples présentés

Measure Signal Similarities

Compare signals with different sample rates or frequency content, measure delays, and determine if there is a signal in a measurement.

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Extracting Classification Features from Physiological Signals

Quantify inter-stride time intervals and measure walking-pattern similarity; construct a feature vector to classify signals.

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Automate Signal Labeling with Custom Functions

Use Signal Labeler to locate and label QRS complexes and R peaks of ECG signals.

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Label Spoken Words in Audio Signals

Use Signal Labeler to label spoken words in an audio signal.

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Label Signal Attributes, Regions of Interest, and Points

Use Signal Labeler to label attributes, regions, and points of interest in a set of whale songs.

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Peak Analysis

Find peaks in a noisy signal and measure their amplitude and the distance between them.

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Detecting Outbreaks and Significant Changes in Signals

Determine significant changes or outbreaks in signals using cumulative sums and changepoint detection.

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Finding a Signal in Data

Find exactly and closely matching signals and allow for variations in sampling by warping the time axis.

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