R: Reads signals from an EDF(+)/BDF(+) file

readEdfSignals {edfReader}

R Documentation

Reads signals from an EDF(+)/BDF(+) file

Description

The function reads ordinary or annotation signals from an EDF(+)/BDF(+) file.

Usage

readEdfSignals(hdr, signals = "All", from = 0, till = Inf,
  physical = TRUE, fragments = FALSE, recordStarts = FALSE,
  mergeASignals = TRUE, simplify = TRUE)

Arguments

`hdr`	An ebdfHeader object read with the readEdfHeader() function.
`signals`	a vector with one or more of the following signal designations: 'All' (default), to include all signals; 'Ordinary', to include all ordinary signals; 'Annotations', to include all annotation signals; signal labels and/or signal names; or signal numbers (numeric or as character).
`from`	numeric, the time in seconds from which the signals shall be read.
`till`	numeric, the time in seconds till which the signals shall be read. The value may exceed the total duration of the recoding.
`physical`	logical, if TRUE (the default) digital samples values are mapped to their physical values, If not, the digital values are returned.
`fragments`	logical, if TRUE discontinuously recorded signals are stored as a list of continuous fragments. If FALSE (the default), a signal is stored as one numeric vector with NA values filling the gaps.
`recordStarts`	logical, if TRUE a data frame with the empty annotations with the data record start time will be included. If FALSE (the default), not.
`mergeASignals`	logical, if TRUE all annotations will be merged into one data frame. If FALSE there will be one data frame per annotation signal.
`simplify`	logical, if TRUE and if there is only one signal read, the signal itself is returned (in stead of a list with that signal as the only one element). If FALSE, this simplification is not performed.

Details

For ordinary signals the from and till parameters are interpreted as [from, till). For annotation signals from-till has to overlap the onset-(onset+duration) period. For for details see the package vignette.

Value

Either a list of one or more signals or a single signal.
The list of signals returned is of class ebdfSignals and a single signal object is of one of the following classes:

ebdfASignal, for an annotation signal
ebdfFSignal, for a fragmented ordinary signal
ebdfCSignal, for a continuous ordinary signal (possible supplemented with NA values)

All classes have supporting print and summary functions. For object details see the package vignette.

Acknowledgement

This package has used code from:

edf.R version 0.3 (27-11-2013), http://feschet.fr/?p=11
the work of Henelius Andreas as of July 2015, https://github.com/bwrc/edf

Examples

# Examples from the vignette
libDir <- system.file ("extdata", package="edfReader")
# a continuous recording
CFile <- paste (libDir, '/edfPlusC.edf', sep='')
CHdr  <- readEdfHeader (CFile)
CSignals <- readEdfSignals (CHdr)            # to read all signals
# read 3 differently designated signals from 5.1 till 18 seconds period
someCSignalsPeriod <- readEdfSignals (CHdr, signals=c(3, "5", "sine 8.5 Hz"), from=5.1, till=18)
someCSignalsPeriod                           # print the signals
summary(someCSignalsPeriod)                  # print singals summary
someCSignalsPeriod$`sine 8.5 Hz`             # print the `sine 8.5 Hz` signal
summary(someCSignalsPeriod$`sine 8.5 Hz`)    # print a `sine 8.5 Hz` signal summary
str(CSignals$`sine 8.5 Hz`)                  # look to the details
# a discontinuous recording
DFile <- paste (libDir, '/edfPlusD.edf', sep='')
DHdr  <- readEdfHeader (DFile)
DSignals <- readEdfSignals (DHdr, fragments=TRUE)    # to read all signals
DSignals$`sine 8.5 Hz`                       # print fragmented signal
summary (DSignals$`sine 8.5 Hz`)             # print fragmented signal summary
str(DSignals$`sine 8.5 Hz`)                  # look to the details

[Package edfReader version 1.2.1 Index]