v are 
leasured 
bution of 
ed under 
on of the 
imuth 180 
sured one 
oot Mean 
fective for 
ince. 
e in wide 
directional 
ce canopy 
5 15 deg. 
ssults are 
be higher 
vs that the 
directional 
t of leaf 
jaring the 
21th, the 
ction, and 
eg. zenith 
J. azimuth 
ference of 
a) Dense plot, V.A.=4. 
      
    
  
sh 
e 
© 
80 
60 
40 
20 
0 
100,2 
807 
60 
40 
20 
Sparse plot, V.A.=4.5deg. 
Calculated reflectance factor (%) 
Back scattering 
c) Dense plot, V.A.=85.5d 
18\7/21 
  
(d) Sparse plot, V.A=85.5deg. 
  
0 | 
-90-60-30 0 30 60 9090-60-30 O 30 60 90 
Forward scattering 
View zenith (deg.) 
Fig. 5. Bidirectional reflectance characteristics obtained by the simulation (condition B-1) 
Therefore, relation between leaf average 
inclination and R(45° )/R(0° ) is analyzed. Where R(¢) 
is the reflectance factor to view zenith angle ¢, 
azimuth angle 180° . Without earlier growth stages 
(without data of sparse plot in june 9th and june 16th), 
the two parameters are adequately correlated. The 
correlation coefficient is 0.84. 
5. CONCLUSION 
NIR bidirectional 
distributions of thirteen kinds of rice canopies are 
simulated using the 3-D monte carlo method and 
measured in an experimental field. The simulation is 
carried out under two different field conditions. One is 
similar to the condition of the experimental field and the 
other is the wide spread field condition under the 
parallel solar beam. The simulated reflectance factors 
under the former condition fit the measured one well. 
As the result of the simulation, the ratio of the 
reflectance factors (view zenith: 45deg. to 0 deg. ) from 
wide spread field is suggested to give average 
inclination of rice canopy. 
In consequence of this research, bidirectional 
reflectance characteristics of rice canopy should be 
analyzed using this model under some kinds of physical 
conditions. 
In this paper, reflectance 
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