29.1.15 DasSpectra
| Topic Version | 1 | Published | 12/09/2016 | ||
| For Standard | PRODML v2.0 | ||||
| Type: | Group | Stereotype: | «XSDcomplexType» | ||
This object contains the attributes of spectra processed data. This includes the spectra data unit, location of the spectra data along the fiber optical path, information about times, (optional) filter related parameters, and UUIDs of the original raw from which the spectra file was processed and/or the UUID of the FBE files that were processed from the spectra files. Note that the actual spectrum data samples and times arrays are not present in the XML files but only in the HDF5 files because of their size. The XML files only contain references to locate the corresponding HDF files containing the actual spectrum samples and times.
|
Name |
Type |
Notes |
|---|---|---|
|
FbeReference |
UuidString |
A universally unique identifier (UUID) of an instance of DAS FBE data. |
|
FilterType |
String64 |
A string describing the type of filter applied by the vendor. Important frequency type filter classes are: frequency response filters (low-pass, high-pass, band-pass, notch filters) and butterworth, chebyshev and bessel filters. The filter type and characteristics applied to the acquired or processed data is important information for end-user applications. |
|
NumberOfLoci |
NonNegativeLong |
The total number of ‘loci’ (acoustic sample points) acquired by the measurement instrument in a single ‘scan’ of the fiber. |
|
OutputDataRate |
FrequencyMeasure |
The rate at which the spectra data is provided for all ‘loci’ (spatial samples). This is typically equal to the interrogation rate/pulse rate of the DAS measurement system or an integer fraction thereof. Note this attribute is mandatory for FBE and spectrum data. For raw data this attribute is optional. |
|
RawReference |
UuidString |
Unique identifier for the HDF5 file containing the raw data. |
|
SpatialSamplingInterval |
LengthMeasure |
The separation between two consecutive ‘spatial sample’ points on the fiber at which the signal is measured. It should not be confused with ‘spatial resolution’. If this data element is present in the DasSpectrum object, then it overwrites the SpatialSamplingInterval value described in DasAcquistion. |
|
SpatialSamplingIntervalUnit |
String64 |
Only required in an HDF5 file to record the unit of measure of the sampling interval of the spectra. |
|
SpectraData |
DasSpectraData |
A DAS array object containing the spectra DAS data. |
|
SpectraDataTime |
DasTimeArray |
A DAS array object containing the sample times corresponding to a single ‘scan’ of the fiber. In a single ‘scan’, the DAS measurement system acquires raw data samples for all the loci specified by StartLocusIndex and NumberOfLoci. The ‘scan’ frequency is equal to the DAS acquisition pulse rate. |
|
SpectraDataUnit |
String64 |
Data unit for the spectra data. |
|
SpectraDescription |
String2000 |
Description of the spectra data. |
|
SpectraIndex |
NonNegativeLong |
The nth count of this Spectra instance in the acquisition. Recommended if there is more than 1 Spectra instance in this acquisition. This index corresponds to the Spectra array number in the H5 file. |
|
StartLocusIndex |
NonNegativeLong |
The first ‘locus’ acquired by the interrogator unit, where ‘Locus Index 0’ is the acoustic sample point at the connector of the measurement instrument. |
|
TransformSize |
NonNegativeLong |
The number of samples used in the TransformType. |
|
TransformType |
String64 |
A string describing the type of mathematical transformation applied by the vendor. Typically this is some type of discrete fast Fourier transform (often abbreviated as DFT, DFFT or FFT). |
|
uuid |
UuidString |
A universally unique identifier (UUID) for an instance of spectra DAS data. |
|
WindowFunction |
String64 |
A string describing the window function applied by the vendor. Examples are "Hamming" or "Hanning". |
|
WindowOverlap |
NonNegativeLong |
The number of sample overlaps between consecutive filter windows applied. |
|
WindowSize |
NonNegativeLong |
The number of samples in the filter window applied. |
|
Association |
Notes |
|---|---|
|
From: DasSpectra.Custom 0..1To: DasCustom Association |
|
|
From: DasProcessed.Spectra 0..*To: DasSpectra Association |