562 
Serie i: 
eI Pu TN 
(2) Calibration Lamp Data Analysis 
agen rm 
Internal calibration lamp data profile for each detector was obtained 
by averaging data within every scan. By monitoring the data profile change, 
an attemp was made to evaluate the calibration lamp data stability, linearity 
and other characteristics. 
ES 
Monitoring was made for two scenes; (a) Detroit, July 25, 82, (b) Chicago, 
Oct 25, 82. An example of the calibration lamp data profile (data (b), Band 
4 Detector 8) is shown in Fig. 4, Features to be noticed are overshootings 
which appear when the calibration lamp status transition occurs and periodic 
level variation within each lamp status. Large overshooting (up to 20%) of 
calibration lamp data was observed for Bands | to 4, while small overshooting 
(up to 52) of calibration lamp data were seen in Bands 5 and 7. It is considered 
due to the different detector types; i.e. Si photodiode for Bands | to 4 and 
InSb photodiode for Bands 5 and 7. Periodic data level changes occur to all 
the bands with periodicity of 6 scans. The exact cause of this periodic data 
level change is not known. 
Relationship between the averaged calibration value of each lamp status 
and then lamp radiance is shown in Fig. 5. As shown in the figure, a good 
linearity holds between the input radiance and then output calibration lamp 
data. In the comparison of calibration data profiles between data (a) and 
data (b), some decrease in gain was observed. The similar decrease in calibra- 
tion lamp level was observed in all bands. Monitoring should be continued 
to decide whether the decrease in gain is due to the detector responsivity 
change or calibration lamp radiacne change. 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
ee SCAN-AVERAGED CAL DATA PROFILE «e so TH ABSOLUTE RADIOMETRIC CALIBRATION ss» 
258 [ zur 
rT I ROW DaF 540 16.« 3 
BAND 3 OTCTR 8 DETECTR = 8 
- A 
288 228 A 
| w 
zi uv 
g p 
üi Au^ ui JY 25.82 Fa 
-J 1sa = WS 2-31 À 
= =i1sg, t 
5 = “ uze 
i g "^ YRS 23-3] 
Ó 19g D 3 74 
zm 
= "f 
7 
sa | 
si e 
8 
1 sa 198 158 298 258 388 
SCAN NO, 8 à ‘ i 
8 S 18 15 28 
ee SCAN-AVERAGED CAL DATA PROFILE se LAMP RADIANCE ON/CM2-SR) 
  
258 Fr 
RECEPTION 821225 
PATH 23 ROW 31 
BAND 3 DTCTR 8 Left:Fig.4 Scan-averaged calibration 
data profile for a scene. 
upper: Detroit, July 25, 22 
lower: Chicago, Oct. 25, 82 
N 
=n 
0 
158 | 
Right:Fig. 5 Relationship between 
lamp radiance and cali- 
bration value. 
(Band 3 Detector 8) 
CAL DATA LEVEL 
mJ 
e 
m 
  
ss 
  
  
  
1 58 188 158 288 258 3988 
SCAN NO.