LumiSpy metadata structure
LumiSpy extends the HyperSpy metadata structure with conventions for metadata specific to its signal types. Refer to the HyperSpy metadata documentation for general metadata fields.
The metadata of any signal objects is stored in the metadata attribute,
which has a tree structure. By convention, the node labels are capitalized and
the ones for leaves are not capitalized. When a leaf contains a quantity that
is not dimensionless, the units can be given in an extra leaf with the same
label followed by the
Besides directly accessing the metadata tree structure, e.g.
s.metadata.Signal.signal_type, the HyperSpy methods
can be used to add to, search for and read from items in the metadata tree,
The luminescence specific metadata structure is represented in the following
tree diagram. The default units are given in parentheses. Details about the
leaves can be found in the following sections of this chapter. Note that not
all types of leaves will apply to every type of measurement. For example,
while parallel acquisition with a CCD is characterized by the
central_wavelength, a serial acquisition with a PMT will require a
start_wavelength and a
metadata ├── General │ └── # see HyperSpy ├── Sample │ └── # see HyperSpy ├── Signal │ ├── signal_type │ ├── quantity │ └── # otherwise see HyperSpy └── Acquisition_instrument ├── Laser / SEM / TEM │ ├── laser_type │ ├── model │ ├── wavelength (nm) │ ├── power (mW) │ ├── objective_magnification │ ├── Filter │ │ ├── filter_type │ │ ├── position │ │ ├── optical_density │ │ ├── cut_on_wavelength (nm) │ │ └── cut_off_wavelength (nm) │ └── # for SEM/TEM see HyperSpy ├── Spectrometer │ ├── model │ ├── acquisition_mode │ ├── entrance_slit_width (mm) │ ├── exit_slit_width (mm) │ ├── central_wavelength (nm) │ ├── start_wavelength (nm) │ ├── step_size (nm) │ ├── Grating │ │ ├── groove_density (grooves/mm) │ │ ├── blazing_angle (º) │ │ └── blazing_wavelength (nm) │ └── Filter │ ├── filter_type │ ├── position │ ├── optical_density │ ├── cut_on_wavelength (nm) │ └── cut_off_wavelength (nm) ├── Detector │ ├── detector_type │ ├── model │ ├── frames │ ├── integration_time (s) │ ├── saturation_fraction │ ├── binning │ ├── processing │ ├── sensor_roi │ └── pixel_size (µm) └── Spectral_image ├── mode ├── drift_correction_periodicity └── drift_correction_units (s)
String that describes the type of signal. The LumiSpy specific signal classes are summarized under Signal types.
The name of the quantity of the “intensity axis” with the units in round brackets if required, for example ‘Intensity (counts/s)’.
See HyperSpy-Metadata-Signal for additional fields.
Laser / SEM / TEM
For SEM or TEM see HyperSpy-Metadata-SEM or HyperSpy-Metadata-TEM.
The type of laser used, e.g. ‘HeCd’.
Model of the laser (branding by manufacturer).
Emission wavelength of the exciting laser in nm.
Measured power of the excitation laser in mW.
Magnification of the microscope objective used to focus the beam to the sample.
Information about additional filters entered into the lightpath before the sample. In case multiple filters are used, they should be numbered Filter_1, etc.
Type of filter (e.g. ‘optical density’, ‘short pass’, ‘long pass’, ‘bandpass’, ‘color’).
Position in the beam (e.g. ‘excitation’ vs. ‘detection’ in case of optical excitation).
Optical density in case of an intensity filter.
Cut on wavelength in nm in case of a long-pass or bandpass filter.
Cut off wavelength in nm in case of a short-pass or bandpass filter.
Contains information about the spectrometer, configuration and grating used for the measurement. In case multiple spectrometers are connected in series, they should be numbered Spectrometer_1, etc.
Model of the spectrometer (branding by manufacturer).
Acquisition mode (e.g. ‘Parallel dispersive’, versus ‘Serial dispersive’).
Width of the entrance slit in mm.
Width of the exit slit (serial acquisition) in mm.
Central wavelength during acquisition (parallel acquisition).
Start wavelength in nm (serial acquisition).
Step size in nm (serial acquisition).
Information of the dispersion grating employed in the measurement.
Density of lines on the grating in grooves/mm.
Angle in degree (º) that the grating is blazed at.
Wavelength that the grating blaze is optimized for in nm.
Information about additional filters entered into the lightpath after the sample. In case multiple filters are used, they should be numbered Filter_1, etc. See Filter above for details on items that may potentially be included.
Contains information about the detector used to acquire the signal. Contained leaves will differ depending on the type of detector.
The type of detector used to acquire the signal (CCD, PMT, StreakCamera, TCSPD).
The model of the used detector.
Number of frames that are summed to yield the total integration time.
- integration_time (s)
Time over which the signal is integrated. In case multiple frames are summed, it is the total exposure time. In case of serial acquisition, it is the dwell time per data point.
Fraction of the signal intensity compared with the saturation threshold of the CCD.
type: tuple of int
A tuple that describes the binning of a parallel detector such a CCD on readout in x and y directions.
Information about automatic processing performed on the data, e.g. ‘dark subtracted’.
type: tuple of int
Tuple of length 2 or 4 that specifies range of pixels on a detector that are read out: (offset x, offset y, size x, size y) for a 2D array detector and (offset, size) for a 1D line detector.
type: float or tuple of float
Size of a pixel in µm. Tuple of length 2 (width, height), when the pixel is not square.
Contains information about mapping parameters, such as step size, drift correction, etc.
Mode of the spectrum image acquisition such as ‘Map’ or ‘Linescan’.
Periodicity of the drift correction in specified units (standard s).
Units of the drift correction such as ‘s’, ‘px’, ‘rows’.