= 544 -
The one part of radiation divided by the focus splitter, is
beamed to view finding system. The shutter, which is in front of
beam splitter has a role of zero adjustment for this instrument.
The continuous interference filter is circular, of which the
half is a visual wave length region, 400-700 nm with the half width
of less than 15 nm, and the other half is near infrared range of
680-1,200 nm with that of 25 nm.
In order to maintain the constant accuracy over the whole wave
length range, the amplification factor of hte main amplifier are
automatical interference filter so that the output of the amplifier
is in constant,
When the standard white is measured on the clear day, the
output of this spectroradiometer was flat for whole wave length
range.
The measuring time, depends upon the revolution of the driving
motor, is varied 10-60 sec. And the output is recorded on the X-Y
recorder or on the data recorder.
The output of the automatic field spectro-meter is defined as:
V=GeLe + Vo
‚where V: output voltage ( Volt )
Le: input radiance for the spectro-radiometer
(uw/ cm? str-nm )
Vo : offset voltage ( Volt )
G: coefficient. i.e. detector's response and gain.
( volt/( #w/ cm”-str-nm ) )
when the rice canopy has a spectral radiance Le-obj(\), a spectral
radiance is defined as:
Le-obj (X\) = V-obj(X\) - Ve(X\) / G(X) xk 8 mirror seve (71)
where Le-obj (A): spectral radiance of the object ( ‘w/ cm” str-nm )
V-obj(N : output voltage for an object ( Volt )
Vo: Offset voltage ( volt )
G(A): constant. i.e. detector's response and gain
j ( volt/ uw/ cm?.str.nm )
mirror (AN: spectral radiance factor of the mirror
: While the spectral radiance of the standard white board observed
directly without the mirror is defined as:
Le-std(\) = V-std(A) - Vo(N / G(N
.................... (2)
,Where Le-std (^J: spectral radiance of the white board
(Aw/ cm?- str: nm )
V.std(»): output voltage for the white board.( volt )
So the spectral radiance factor of the object is defined as:
obj (^) = Le-0bj CJ) / Le-std(N
( V:0bj C9 - Vo(XN) ) x Óstd (^)
ÜV-stdG) - V»0) ) xàámirror() c3)
