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Combination of green and blue bands. Three catego- 
ries, namely, paddy freshly planted {A1.1), paddy 
harvested (Al.h) and fallow land (A10), are classi- 
fied with sufficient accuracy. Paddy mature (Al.3) 
is misclassified as sugarcane young ratoon (A2.2). 
Comparison of the histograms (Fig.5) for these two 
categories shows inadequate separability. 
ii) Combination of blue and red bands. Paddy freshly 
planted (A1.1), Paddy harvested (Al.4) and fallow 
land (AlO) are classified with good accuracy, as 
for the combination of green and blue bands.Histo- 
grams for the various categories (Fig.5) suggest 
that categories not separable in the green band are 
also not separable in the red band. 
iii) Combination of red and green bands. Paddy harvested 
(Al.h) and fallow land (A10) can be classified with 
good accuracy. However, about half of paddy freshly 
planted (Al.1) is misclassified as sugarcane young 
ratoon (A2.2). An important result is that this 
band pair is possibly the best for the classification 
of paddy well grown (Al.2). 
iv) Combination of blue, green and red bands. Evidently, 
there is no improvement in classification accuracy 
with respect to paddy mature (Al.3), sugarcane fresh- 
ly planted (A2.1) and sugarcane well grown (42.3), 
over that obtained from a combination of any two 
bands. As in the case of the two-category classifi- 
cation result (Table 1) for paddy well grown (A1.2) 
and sugarcane young ratoon (A2.2), for instance, here 
also more than half of Al.2 is misclassified as A2.2; 
most of A1.3 is misclassified as A2.2; more than half 
of A2.1 is misclassified as Al.1l; and about half of 
A2.3 is misclassified as Al.l. 
4. Conclusions Digital analysis of aerial color infrared fra- 
mes of agricultural scenes (containing paddy and sugarcane) appee 
ars to be a feasible method for classfication (and hence for acre 
acreage and yield estimates) of the crops in the area under study. 
However, choice of optimum bands (even in the visible + near infra 
red portions of the electromagnetic spectrum), which is definite- 
ly dependent on the season (or time) of acauiring the data, for 
all the various categories (in different stages of growth Y is 
still to be established. As regards the widespread aoplication of 
such an analysis, more basic work is to be done. 
Further Acknowledgements This work was carried out under a resea- 
rch project sponsored and funded by the Indian Space Research Or- 
ganization, Department of Space, Goverment of India. 
Thanks are due to Professor G.Krishna and Group (Indian Ins- 
titute of Science) for their valuable assistance in the digitiza- 
tion of the picture data.