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CARP Documentation

AccelerationFeatures

A set of acceleration (non-gravitational) features collected over a specific sampling period.

Collected by AccelerometerFeaturesProbe for the SensorSamplingPackage.ACCELERATION_FEATURES measure. Each feature is calculated per axis (x, y, z prefix), in m/s^2 or as a count.

The set of features is inspired from the Medium article on Feature Engineering on Time-Series Data for Human Activity Recognition and contains the following 15 simple statistical features:

  1. mean
  2. standard deviation
  3. average absolute deviation
  4. minimum value
  5. maximum value
  6. difference of maximum and minimum values
  7. median
  8. median absolute deviation
  9. inter-quartile range
  10. negative values count
  11. positive values count
  12. number of values above mean
  13. energy
  14. average resultant acceleration
  15. signal magnitude area

Most of these features are self-explanatory, except:

  • Energy of a signal in every axis is computed by taking the mean of sum of squares of the values in a window in that particular axis.
  • Average resultant acceleration over the window is computed by taking average of the square roots of the values in each of the three axis squared and added together.
  • Signal magnitude area is defined as the sum of absolute values of the three axis averaged over a window.
Inheritance
Annotations

Constructors

AccelerationFeatures.fromAccelerometerReadings

AccelerationFeatures.fromAccelerometerReadings(
  1. List<UserAccelerometerEvent> readings
)

Calculates the features from a non-empty list of accelerometer readings.

AccelerationFeatures.fromJson

AccelerationFeatures.fromJson(
  1. Map<String, dynamic> json
)

AccelerationFeatures

AccelerationFeatures()

Properties

avgResultAcceleration

num? avgResultAcceleration
getter/setter pair

count

int count
getter/setter pair

The number of accelerometer readings the features are calculated from.

fromJsonFunction

Function get fromJsonFunction
override

The function which can convert a JSON string to an object of this type.

signalMagnitudeArea

num? signalMagnitudeArea
getter/setter pair

xAad

num? xAad
getter/setter pair

xAboveMean

num? xAboveMean
getter/setter pair

xEnergy

num? xEnergy
getter/setter pair

xIqr

num? xIqr
getter/setter pair

xMad

num? xMad
getter/setter pair

xMax

num? xMax
getter/setter pair

xMaxMinDiff

num? xMaxMinDiff
getter/setter pair

xMean

num? xMean
getter/setter pair

xMedian

num? xMedian
getter/setter pair

xMin

num? xMin
getter/setter pair

xNegCount

num? xNegCount
getter/setter pair

xPosCount

num? xPosCount
getter/setter pair

xStd

num? xStd
getter/setter pair

yAad

num? yAad
getter/setter pair

yAboveMean

num? yAboveMean
getter/setter pair

yEnergy

num? yEnergy
getter/setter pair

yIqr

num? yIqr
getter/setter pair

yMad

num? yMad
getter/setter pair

yMax

num? yMax
getter/setter pair

yMaxMinDiff

num? yMaxMinDiff
getter/setter pair

yMean

num? yMean
getter/setter pair

yMedian

num? yMedian
getter/setter pair

yMin

num? yMin
getter/setter pair

yNegCount

num? yNegCount
getter/setter pair

yPosCount

num? yPosCount
getter/setter pair

yStd

num? yStd
getter/setter pair

zAad

num? zAad
getter/setter pair

zAboveMean

num? zAboveMean
getter/setter pair

zEnergy

num? zEnergy
getter/setter pair

zIqr

num? zIqr
getter/setter pair

zMad

num? zMad
getter/setter pair

zMax

num? zMax
getter/setter pair

zMaxMinDiff

num? zMaxMinDiff
getter/setter pair

zMean

num? zMean
getter/setter pair

zMedian

num? zMedian
getter/setter pair

zMin

num? zMin
getter/setter pair

zNegCount

num? zNegCount
getter/setter pair

zPosCount

num? zPosCount
getter/setter pair

zStd

num? zStd
getter/setter pair

Methods

toJson

Map<String, dynamic> toJson()
override

Return a JSON encoding of this object.