如何用erdas计算表观反射率2、ConversiontoTOAReflectance表观反射率OLIbanddatacanalsobeconvertedtoTOA（TOPOFATMOSPHERE）planetary行星reflectanceusingreflectancerescalingcoefficientsprovidedintheproductmetadata

Question

如何用erdas计算表观反射率
2、Conversion to TOA Reflectance表观反射率
OLI band data can also be converted to TOA（TOP OF ATMOSPHERE） planetary行星 reflectance usingreflectance rescaling coefficients provided in the product metadata file (MTLfile).The following equation is used to convert DN values to TOAreflectance for OLI data as follows:
ρλ' = MρQcal + Aρ
where:
ρλ' = TOA planetary reflectance,without correction for solar angle.Note that ρλ' does not contain acorrection for the sun angle.
Mρ = Band-specific multiplicative rescaling factor from the metadata(REFLECTANCE_MULT_BAND_x,where x is the band number) ——头文件MTL file
Aρ = Band-specific additive rescaling factor from the metadata(REFLECTANCE_ADD_BAND_x,where x is the band number) ——头文件MTL file
Qcal = Quantized and calibrated standard product pixel values (DN)
3、TOA reflectance with a correction for the sun angle isthen:
ρλ =
ρλ'
=
ρλ'
cos(θSZ)
sin(θSE)
where:
ρλ = TOA planetary reflectance
θSE = Local sun elevation angle.The scene center sun elevation angle in degrees isprovided in the metadata (SUN_ELEVATION).太阳高度角——头文件MTL file
θSZ = Local solar zenith angle; θSZ = 90° - θSE 太阳天顶角
For more accuratereflectance calculations,per pixel solar angles could be used instead of thescene center solar angle,but per pixel solar zenith angles are not currentlyprovided with the Landsat 8 products.
（这一段话该如何理解?）

Answer 1

这个应该是解释计算原理的,如果你只需要出结果的话不需要理解这个,只需要知道在软件里怎么操作就好了