The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008 
4. DISCUSSION 
The complexity of the pre-processing of dual-view FIGOS data 
prior to BRF retrieval is mainly due to the characteristics of the 
different instruments involved. Ideally, the irradiance should be 
measured at the same temporal and spectral resolution and 
wavelength range as the reflected radiance. Thus, a device that 
could capture direct and angularly resolved diffuse irradiance at 
a sampling rate equal to the target reflectance acquisition time 
would be highly desirable. This would provide a complete 
angular characterisation of the irradiance distribution for each 
spectrodirectional target measurement. 
The use of several instruments requires intercalibrations. The 
storage of according intercalibration factors in the spectral 
database enables the automation of intercalibration. Similarly, 
the storage of Spectralon characteristics, i.e. factors describing 
deviations from the ideal Lambertian . reflector, allows 
correcting measurements for these imperfections (Hüni et al., 
2008). While Spectralon factors can be considered part of the 
metadata space of spectral data, the same does not strictly apply 
to intercalibration factors. The latter are rather metadata of the 
instruments. However, their storage within a spectral database 
is important as they can tie spectra to some common reference 
instrument. Such capability is highly desirable when dealing 
with campaigns involving many different instruments, e.g. 
round robin experiments as planned in the Hyper-I-Net project 
(Nieke et al., 2007). 
The concept of the Space Processing Chain is using the 
SPECCHIO database as data source to build the chain input 
spaces. All spaces are then held in memory, leaving the original 
information in the database untouched. Chain outputs are not 
stored in the SPECCHIO database but can be exported to files 
or stored in specialised reference databases (Hueni et al., 2008). 
Due to the flexible and fast processing capabilities of the 
SPECCHIO Space Chain, reprocessing of original data is far 
easier than managing products by keeping track of all involved 
module parameters. It is however foreseen to implement the 
storage of chain configurations in the database or in 
configuration files. This will enable users to store and reload 
typical chain settings. 
5. CONCLUSIONS 
The automated pre-processing of dual-view FIGOS data is an 
important step towards an operational BRF retrieval. The 
utilisation of a database combined with a flexible, configurable 
processing chain allows dealing with the complex processing 
needs arising from instrument intercalibrations and differing 
spectral and temporal resolutions of the field data sets. 
The generic, modular approach to processing of spectral data 
will enable the application of processing components to datasets 
acquired with different sensors, thus making the system useful 
for other research groups. 
The inclusion of instrument intercalibration data in the database 
model is enabling the SPECCHIO system to be used in round 
robin experiments and is an important step towards comparable 
datasets in multi-instrument campaigns and, ultimately, better 
data quality. 
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