CLASSIFICATION
The classification process can be described by the order of
the numerical computations used in partitioning the signal
space. The use of a clustering algorithm for classification
is performed in a manner similar to LARSYS,i.e., the maximum
likelihood classification, putting the emphasis on the super
vised one. The partition of the color space is performed by
the use of the discriminant G.(x) for multivariate Gaussian
1
density functions of the data vector x
G ± (x) =logP (w ± ) -nlog (2tt) /2-log | K . | /2- (X-M.) T K i _1 (X-M ± ) /2 , (9)
where P(w.) is the apriori probability for the pattern class
i, M. is the mean value vector of the pattern class i, and
K. is the covariance matrix of the pattern class i. The fol
lowing inequality for all i^j
G i (x)>G^(x) (j=l, 2, ,n) (10)
gives such criterion that the data vector x belongs to the
class w..
l
The particulate method being used determines the form of the
quadratic classifier. The unknown parameters in these dis-
crimants are determined in a preliminary process call and
training, via the supervised algorithm, when one is supplied
with a set of training sample patterns of known classifica
tion. In other words, these samples are used to develope dis
criminants, which may then be used to classify ^unknown sam
ples. Then, so far as the training samples are truely repre
sentative of the classes and the discriminant is appropriat
ely computed, the classification will be reasonably reliable.
Thus, a crucial aspect of the classification procedure is the
election of training samples. It is accomplished by visual
inspection of the imagery, coupled with additional sources
of such informations as the topographic maps, aircraft pho-
tographes, and personal knowledge of the area. In the pre
sent stu^y, training data are selected from Kanazawa area
in 300km , which includes a portion of Japan sea, Kanazawa
harbor,Kahoku lagoon, Asano- and Sai-rivers, Kanazawa city,
and its outskirts. The line and sample coordinates of the
selected area are determined from a computer line printer
diaplay ,because of the readily identifiable pixels. If the
training site boundaries indicated on the classification
map are not adequate because of misclassification, the trai
ning site selection may be iterated until the satisfactory
data are obtained. The classes are given in Table 3 and Fig.3.
No
1
2
3
4
5
Table 3 List o
Classes Locations
Sea Uchinada offshore
Lagoon Kahoku lagoon
Beach Uchinada seabeach
Bared soil Race track
and grass
Residential Uchinada
area town
f land use classes
No classes Locations
6 Urban area Musashi quar-
Harvested
ter in city
field Outskirts of town
8 Farm Outskirts of town
9 Coniferous Mountain on
trees city
10 Broad- Mountain on
leaved trees town
11 River,bank Kanakusare-kawa