PRINTER CRT 
  
  
  
  
  
  
640& X400,X8s5i1cv X3ca4 X | FRAMES 
  
  
DISPLAY HEHORY FLOPPY DISK DRIVE 
  
  
  
  
  
KEYBOARD 32BIT/16BIT 
PERSONAL COMPUTER 
HOUSE laze J 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
DIGITIZER 
  
  
  
Fig. 2 CASYII System Configuration 
  
Fig. 3 Operation of CASYII 
2.4.2 Functions 
CASYII has various functions as follows. 
(1)Image Display 
CASYII has a full color display memory 
and two 8 color image display memories 
which allow users to display false color 
images and pseudo color images. 
(2)Flicker & Overlay 
CASYII can alternatively display(flicker) 
two images stored in the two 8 color 
display memories. These images can be 
overlaid on the full color image as well. 
(3)Area extraction 
By using a mouse, users can extract cer- 
tain areas from the display. 
(4)Inter-display memory execution 
Logical execution(AND,OR, XOR etc.) can be 
performed between the two 8 color display 
memories. 
3. METHODOLOGY 
3.1 Pre Processing 
In order to overlay the satellite data 
with grid type land use data, it is neces- 
sary to perform geometric correction to 
the data. Further, due to the display 
size limitation(640x400) of the personal 
computers, both satellite and land use 
data must be divided into smaller unit 
size. 
3.1.1 Geometric Correction 
In this step, SPOT panchromatic data and 
TM data are geometrically corrected to 
overlay on old land use data. 
3.1.2 SPOT/TM Data Composite Using HSI 
Transformation 
In order to integrate SPOT PA data with 
TM data, HSI transformation is performed 
to the both data. Fig.4 shows the concept 
of SPOT data composite using HSI transfor- 
mation. 
  
  
  
TM 
SPOT PA 
Band2:Blue | Band3:Green | Band4:Red 
  
  
  
  
| | | 
H S I Transformation | 
  
  
  
] ] 
Hue | [saturation | [Intensi ty | Intensity 
| | 
HS I Inverse Transformation 
  
ps 
| SPOT/TM Composite Color Image | 
  
Fig. 4 Concept of SPOT/TM composite using 
HSI transformation 
3.1.3 NVI Data Produetion 
To support land use data updating proce- 
dure, the Normalized Vegetation Index(NVI) 
was computed from TM data using the fol- 
lowing formula. 
Band 4 - Band 3 
NVI = x 100 + 128 
Band 4 + Band 3 
  
3.1.4 Sub-division of Data 
Pre-processed SPOT/TM data, NVI data and 
old land use data are sub-divided into a 
processing unit size and stored in floppy 
disks to transfer data to personal comput- 
ers. The data amount of one processing 
unit size are as follows. 
  
SPOT/TM Data: 512 Pixel X 400 Lines 
x 3 Ch 
NVI Data: 512 Pixel X 400 Lines X 1 Ch 
Old Land Use Data : 512 Pixel X 400 Lines 
x1 €h 
3.2 Land Use Data Updating Procedure 
The pre-processed data will be provided to 
the personal computer based interactive 
processing sub-system and the old land use 
data are updated. Fig.5 shows the main 
flow of the concept of the updating proce- 
dure. 
3.2.1 Water/Vegetation/Non-Vegetation 
Discrimination 
(l)Firstly, SPOT/TM false color image is 
displayed on the CRT(see Fig.6(a)). 
(2)The NVI level sliced image is overlaid 
on the false color image and the thresh- 
old level for discriminating water areas 
from land areas is selected. 
(3)similarlyv, the threshold level for 
dividing land areas into vegetation areas 
and non-vegetation areas is selected. 
124 
3.2.2 
(1)T| 
item: 
data 
the 
Fig6 
Proce 
(2)T 
yell 
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(3) TI 
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(4)T 
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