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AGREEMENTS FOR THE SPECTRAL MEASUREMENTS IN JAPAN
In Japan, the spectral radiance factor is measured standing upon
the standard white, where the radiance factor as the reflection
quantity of the object recomended by CIE, is used.
At present, the spectral radiometer is under construction and
the way of the measurement is under way, and the reflectance factor
will be demonstrated in the future.
Now, the following items should be written in addition when
measuring the radiance factor:
Sun's altitude
thé azimuth of tbe observation
the degree and the type of the cloudness
the instantaneous field of view of the measuring instrument
the type of the used reflection standard
the observation time and date
the degree of the haze (slant visual range)
the number of the measurements.
[e WN
°
The standard white: Kodak white reflectance paint, which is
calibrated to a smoked Mgo, will be in
general use.
*The accuracy of the measured spectral signature of the certain
object.
The measured value of the certain objects in the open-air will
be greatly influenced with the observation direction, sun altitude,
and the weather in addition to the accuracy of the spectroradio
meter. So the accuracy of the measurement will be more high when
the high accurate instruments are applied, in a short observation
time(e.g. in a few second or so), and when the measurements are
repeated. For this purpose, the experiments should be repeated with
the new high accurate instruments.