Overview

An EDF parser written in coffee-script.

Primarily used for Polysomnographic signals, the EDF file format is multi-channel, supports multiple sampling rates on a per channel basis, and provides for an unlimited number of channels. More information can be found on the wikipedia article.

Usage and Examples

A simple Example

util	= require "util"
edf		= require "edf"

# Create a new instance of edf.EDFFile.
my_edf = new edf.EDFFile "./path/to/some.edf"

# Get some information about the file.
file_duration	= my_edf.get_file_duration( )
num_signals		= my_edf.get_header_item "num_signals_in_data_record"

util.log "The file is " + file_duration + " seconds in length."
util.log "There are " + num_signals + " signals in this file."

# Get some information about the signals.
for signal_index in [0..num_signals-1]
	signal_label	= my_edf.get_signal_item signal_index, "label"
	sample_rate		= my_edf.get_header_item( "duration_of_data_record" ) / my_edf.get_signal_item( signal_index, "num_samples_in_data_record" )
	min				= my_edf.get_signal_item signal_index, "physical_min"
	max				= my_edf.get_signal_item signal_index, "physical_max"

	util.log signal_label + " has a sampling rate of " + sample_rate + " Hz."
	util.log signal_label + " has a min and max of " + min + ": " + max  + "."

Available header information

The following items are available in the EDF header and can be accessed by using get_header_item.

• version
• patient_id
• recording_id
• start_date
• start_time
• number_of_bytes
• reserved
• num_data_records
• duration_of_data_record
• num_signals_in_data_record

These items are available using get_signal_item. A signal index must be passed along as the first argument.

• label
• transducer_type
• physical_dimensions
• physical_min
• physical_max
• digital_min
• digital_max
• prefiltering
• num_samples_in_data_record

License

Three clause BSD. See LICENSE.

Thanks

Original work sponsored by Younes Sleep Technologies.