r— Data
A
— Digital Image
Collection E By Digitizer
Key Board Input
Plane Information
— Data Compilation + Point Information
Line Information
Digital Image Display
Calculation Normalized Vegetation Index
Histogram Measurement
Processing — Density Slicing Processing
—1 — Binary Image Production
— Landcover Change Detection Using Binary Image
Display [Display Statistical Information
— Image and —j]— Display Raster Data
Statistical — Display DIgital Image Data
Information '— Display Stored Image
— Town Evaluation by Statistical Data
Evaluation for — Masking Operation and Result Summation
LE Regional ——]- Overlay Processing
Characteristics — Integrated Result Summation
Fig.2 Software Configuration
3. Fundamental Training
3.1 Basic Principles of remote sensing
The meaning of "Remote Sensing" is to
observe and measure various kinds of earth
surface informations. Every substance on
the earth has its own characteristics of
reflection and absorption in different
wavelength of radio wave. Applying this
principle, detailed surface conditions can
be assumed by measuring reflected and
radiated intensity from each substance in
some wavelength. These techniques are
basic principles of remote sensing.
Through the training of digital image
processing, trainees can understand digi-
tal image data structure, what meaning.
multispectral data is, basic technique of
digital image processing and what kinds of
informations are obtained from remote
sensing data.
(a) Digital Image Data
Typical remote sensing data such as
Landsat MSS, TM, SPOT is stored in some
secondary memory device.
RESTEC has been distributing these
kinds of remote sensing digital image data
by computer compatible tape (CCT) and
floppy disk. BIL and BSQ format are adopt-
ed for data storing. Therefore the data
Table 1 Format of IBM Type Floppy Disk
Items Contents
Recording Form Two-sided,
Double density
Memory Capacity 1 M Byte
Cylinder No. 77 Cyliners
Track No. 154 tracks
(2 tracks/cylinder)
26 sectors/track
256 byte/sector
Sector No.
Sector Length
Data Format of Satellite Data
Floppy Disk
Table 2
Logical Format File Constitution
Data
BIL Header
( 1 file.) 512byte| 512p X 4001 X 4B
Data
BSQ Header
( 4 files ) |512byte| 512p X 4001 X IB
format in floppy disk has also
decided.The disk format and data constitu-
tion for floppy disk are shown in Table 1
and 2 respectively.
(b) Multi-Spectral Data
Remote sensing can observe the var-
ious earth surface informations in the
different wavelength (i.e. spectral band)
such as visible and near infrared region.
Most of remote sensing sensors have sever-
al observation instruments. For instance
Landsat TM has a scanning optical-
mechanical sensor system that observes
visible, reflective-infrared, middle-
infrared, and thermal-infrared regions of
spectral wavelength. Collecting digital
image data that consists of several kinds
of speetral informations is so called
multi-spectral data.
(c) Initial Statistics Extraction
Single band data of remote sensing is
expressed by brightness value with the
location, composed of rows and columns.
Generally the brightness value will range
from 0 to 255 (-28). It is called 8 bit
image.
The histogram measurement function is
necessary for an analyst to understand the
actual digital image data distribution. In
this training, trainees can recognize what
meaning of 8 bit image data is by display-
ing the result of single band histogram
measurement.
(d) Band ratio
Typical characteristics of spectral
reflectance for healthy, dead vegetation
and dry soil are shown in Fig.3. Healthy
vegetation generally reflects from 40 to
50% of incident near-infrared energy, with
chlorophyll in it absorbs about 80 to 90%
of incident of visible region. Dead vege-
tation has higher reflectance than healthy
vegetation in visible spectrum and has
lower reflectance in reflected-infrared
region.
From mentioned basic principle, the
difference and ratio of brightness values
between visible and near infrared band
suppose to be effective for the vegetation
monitoring. The red/infrared ratio data
