Rgb Lasersysteme QWAVE UV Lux-Meter, illumination measuring device, Brightness meter, DSA491006 Datenbogen
Produktcode
DSA491006
Operation
15
combo box select the type of light source used. If you don’t find your light source in the
list, you need to supply your own calibration lines. In this case, please take a look at the
“CalibrationLines xxx.dat” files in the installation folder on your hard drive and
create a new similar file containing the spectrum lines of your light source.
list, you need to supply your own calibration lines. In this case, please take a look at the
“CalibrationLines xxx.dat” files in the installation folder on your hard drive and
create a new similar file containing the spectrum lines of your light source.
After you have selected your light source, click on “Start Fit”. The software tries to match
the peaks in the measured spectrum and the given spectrum lines for your light source
automatically. Not all of the given spectrum lines have to be present in the measured
spectrum, but all measured peaks must be known spectrum lines. If a match has been
found, the average deviation is displayed. If the match seems to be successful, it is
displayed in green, otherwise in red. You can also graphically display the deviations by
clicking on “Show Deviations”. If the measured peaks have successfully been identified,
you can set the four new wavelength calibration parameters by clicking on the “Save”
button and confirm by clicking “OK”. The new wavelength calibration is then saved to the
device.
the peaks in the measured spectrum and the given spectrum lines for your light source
automatically. Not all of the given spectrum lines have to be present in the measured
spectrum, but all measured peaks must be known spectrum lines. If a match has been
found, the average deviation is displayed. If the match seems to be successful, it is
displayed in green, otherwise in red. You can also graphically display the deviations by
clicking on “Show Deviations”. If the measured peaks have successfully been identified,
you can set the four new wavelength calibration parameters by clicking on the “Save”
button and confirm by clicking “OK”. The new wavelength calibration is then saved to the
device.
Dark Spectra
Inside the Qwave spectrometer, the spectra are detected with a CCD line sensor. Like all
image sensors, this sensor detects a small signal even if there is no light entering the
spectrometer. This signal depends on the individual pixel, the exposure time and the
temperature. In order to obtain a precise measurement with a small noise level, this “Dark
Spectrum” must be taken while no light enters the spectrometer and then subtracted
from the actual measurement.
image sensors, this sensor detects a small signal even if there is no light entering the
spectrometer. This signal depends on the individual pixel, the exposure time and the
temperature. In order to obtain a precise measurement with a small noise level, this “Dark
Spectrum” must be taken while no light enters the spectrometer and then subtracted
from the actual measurement.
For your Qwave spectrometer, this dark spectrum has already been taken, is stored in the
device and automatically subtracted from the measured spectrum each time you take a
new spectrum. Because the dark spectrum depends on the exposure time in a non-linear
way, there are actually multiple dark spectra stored in the device for a certain number of
exposure times. The dark spectrum that is needed for a chosen exposure time is then
obtained by interpolating between these dark spectra.
device and automatically subtracted from the measured spectrum each time you take a
new spectrum. Because the dark spectrum depends on the exposure time in a non-linear
way, there are actually multiple dark spectra stored in the device for a certain number of
exposure times. The dark spectrum that is needed for a chosen exposure time is then
obtained by interpolating between these dark spectra.
In case you find that the spectra you get are not zero on the average, even if no light
enters the spectrometer, then you probably need to recalibrate the dark spectra. You can
also check the dark spectrum calibration using the “Calibrate Dark Spectrum” window
(see below).
enters the spectrometer, then you probably need to recalibrate the dark spectra. You can
also check the dark spectrum calibration using the “Calibrate Dark Spectrum” window
(see below).
To recalibrate the dark spectra, simply close the spectrometer entrance, make sure that
no light enters the device and choose “Calibrate Dark Spectrum” from the Tools menu.
Then click the “Take” button and go for a coffee. After a few minutes the software has
taken dark spectra for a series of exposure times. You can check the new dark spectra by
clicking on the “Test Button”. While the test is running, you can in the lower diagram the
spectra taken without (red) and with (green) dark spectrum correction. In the upper
diagram you can see the noise level, also without (red) and with (green) dark spectrum
correction for a series of exposure times. You can see that the noise level of the raw data
(red) increases significantly with increasing exposure time. With dark spectrum correction
(green) however, the noise level should remain pretty much at the same level for
no light enters the device and choose “Calibrate Dark Spectrum” from the Tools menu.
Then click the “Take” button and go for a coffee. After a few minutes the software has
taken dark spectra for a series of exposure times. You can check the new dark spectra by
clicking on the “Test Button”. While the test is running, you can in the lower diagram the
spectra taken without (red) and with (green) dark spectrum correction. In the upper
diagram you can see the noise level, also without (red) and with (green) dark spectrum
correction for a series of exposure times. You can see that the noise level of the raw data
(red) increases significantly with increasing exposure time. With dark spectrum correction
(green) however, the noise level should remain pretty much at the same level for