ASD FieldSpec 3, Руководство пользователя

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ASD Document 600540 Rev. J 81 FieldSpec® 3 User Manual
www.asdi.com Appendix B Reference Information
B.1.4 How often do I need to optimize?
Optimization has no affect on the data unless the measurement has drifted
towards saturation, in which case optimization is mandatory. The RS
3
application provides a saturation warning.
B.1.5 How often do I need a (baseline) White Reference?
Inside Use or Constant Lighting Conditions
When using the instrument inside under constant lighting conditions or when
using an accessory with its own light source, collect a (baseline) white
reference every 10 to 15 minutes while the instrument is warming up and then
every 30 minutes thereafter.
Outside Use
When using the instrument outside, you should collect a new white reference
frequently for:
• solar changes, like the sun’s angle in the sky where 10 minutes can
represent a change in the measurement;
• atmospheric changes, like blue sky, cloud cover, humidity, or water vapor
• temperature changes
• accessory changes (like switching probes)
It is important that the light intensity is the same for when the white reference
is collected as for the measurements of the sample.
An experiment to perform when outside is to continue to take measurements
of the white reference panel and observe the stability of the white reference
line. This will give you an idea of how the current fluctuations in weather
affect your measurements.
B.1.6 What spectrum average (or sample count) should I use?
When outside, it is usually sufficient to use 30 scans in the spectrum
averaging for the sample and 60 scans for the white reference. The white
reference isn’t taken as often, which is why you would want to include more
scans in its averaging.