Table of Contents
Advertisement
Appendix B Reference Information
B.1
Frequently Asked Questions (FAQ)
B.1.1
What is a spectroradiometer?
© 2010 ASD Inc.
Spectrograph - An optical instrument for forming the spectrum of a light
source and recording it on a film. The dispersing medium may be a prism or a
diffraction grating. This term was common prior to the digital age. ASD
instruments do not use film.
Spectrometer - An optical instrument which uses detectors other than
photographic film to measure the distribution of radiation in a particular
wavelength region. All ASD instruments are spectrometers.
Spectroradiometer - An optical instrument for measuring the radiant energy
(radiance or irradiance) from a source at each wavelength throughout the
spectrum. A spectroradiometer is a special kind of spectrometer.
Note:
Only the FieldSpec spectrometer is configured as a
spectroradiometer. The reason is that the fiberoptic cable significantly
affects the calibration required to measure radiance. The FieldSpec
instrument has a fixed fiberoptic cable routed directly through the
front panel to the internal spectrometers, while the other ASD
spectrometers are designed to detach and even interchange fiberoptic
cables. To be meaningful, radiance measurements with
non-FieldSpec instruments would have to be performed using the
same fiberoptic cable and the same connector orientation of
the plugged in fiberoptic cable as the factory calibration.
The SWIR component of the ASD spectrometer is a scanning spectrometer,
while the VNIR component is an array spectrometer.
79
FieldSpec® 3 User Manual
Hide quick links:
Advertisement
Table of Contents
