edfReader (version 1.2.1)

readEdfSignals: 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.

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

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.

See Also

edfReader, readEdfHeader For the vignette use the console command: vignette('edfReaderVignette', package = "edfReader") or click on Index below.

Examples

# NOT RUN {
# 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
# }