Development of a Radiometric Correction Algorithm for OCTS Data
(2)Principals
The calculation method of gain parameter shows the next equation.
Gain =TL(I, q) x (1 + Bd(Td-Td0) x (1 + Bp(Tp-Tp0) x (1 + Bam(Tam-Tam0) x (1 +Bad(Tad-Tad0)
Where;
I: band number
q: tilt angle
TL : reflectance correlation function by tilt
Bd: temperature correlation function by detector
Td : temperature of detector
Td0: origin temperature of detector
Bp: temperature correlation function by pre-amplifire
Tp: temperature of pre-amplifire
Tpo: origin temperature of pre-amplifire
Bam: temperature of AMUX
Tam0:origin temperature of AMUX
Bad: temperature correlation function by ADC
Tad: temperature of ADC
Tad0: origin temperature of ADC
The calculation method of brightness shows the next equation
Where;
AD:A/D conversion function
VC : OCTS data
Of : total offset
Ga: Total Gain
Gain: gain coefficient by equation 1.
2.2 Thermal Infrared
Band 9 to band 12 of OCTS data are thermal infrared spectral band. The radiometric algorithm is shown in nest step.
-
Calculation of original black body temperature
- Input Brightness of black body
- Calculation the average of black body except abnormal value
- Input total offset
- Calculation of correlation coefficient
- Calculation of Brightness
- Calculation of albedo
Five black body are loaded on near OCTS senor. Normally, number 1 to 4 of the black body are used. Number 5 black body is compared when number 1 to 4 of the black body output abnormal value.
The correlation coefficient is leaded by next equation.
Where:
VB: average of Black body
O: total gain
