THE EXPANDED PDCS DIGITAL IMAGE PROCESSING SYSTEM (EPDCS) 
by 
GUAN-HUA XU 
Chinese Academy of Forestry 
Wan Shou Shan, Peking, CHINA 
Abstract 
This paper is a research report describing the Computer 
Software System EPDCS, developed for processing remote 
sensing imagery data. The programme system has grown 
out of the PDCS programmes which the author developed 
and implemented in Sweden. 
The system includes the following groups of programmes: 
- Tape handling and subscene extraction 
- Image correction and restoration 
- Image enhancement 
- Greyscale picture and statistics histogramme print 
and display 
- Supervised classification 
- Unsupervised classification 
— Cleaning-up of a classified map 
— Accuracy evaluation 
- Result output 
In this paper, discussions are made about the techniques 
for the preprocessing, enhancement and classification of 
MSS data, with greater elaboration on the classification. 
EPDCS includes three different methods for the Su- 
pervised classification and three different methods for 
the unsupervised classification. One of these methods 
can function to classify digital images by utilizing 
both Spectral and spatial characteristics and another 
one of then can do.So by applying the theory of Fuzzy 
pattern recognition. 
The system has been used in land use mapping and 
environmental monitoring. The results have shown some 
promise of usability in practical work and will be 
reported in another paper. 
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