OpenXDF

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OpenXDF is an open standard for the digital storage of time-series physiological signals and annotations based on XML. The primary focus is on electroencephalography and polysomnography. OpenXDF was created based on the need for interoperability and free data exchange in polysomnography. OpenXDF uses a two file structure where the time-series data is stored in data blocks in a binary file while the patient information, annotations, and the binary file description is stored in a separate XML header file.

The goal of the OpenXDF initiative is to provide a method by which physiological data can be shared among researchers and clinicians regardless of the device used to acquire the data. This is an on-going initiative supported by the OpenXDF web site.

1 Two-File Format
2 EDF (European Data Format)
3 References
4 External links

[edit] Two-File Format

Since XML uses text tags to describe content, it creates larger files than comparable binary storage formats. For polygraph recordings this increase in file size would be prohibitive. A typical polysomnogram (digitally stored sleep polygraph) can exceed 300 megabytes in its raw binary form. If the binary waveform data is stored separately from the descriptive data such as patient information, montages, and annotations, this problem is alleviated. Also multiple waveform files can be linked under a single OpenXDF header file, and existing formats can be adapted without converting the binary waveform data.

[edit] EDF (European Data Format)

European data format(EDF) was created in 1992 to provide an open file format for time-series data. It has been the defacto standard for sharing data in the EEG and sleep fields since its inception. EDF is not based on an extensible format, and so can be limited in its application. Rather than supplant EDF, OpenXDF was designed such that an OpenXDF header can be added to an EDF file to extend its capabilities.