In: Wagner W.. Székely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Yol. XXXVIII, Part 7B 
headings have to be aligned to within ±25° with the sun azimuth 
of the expected flight time and day in order to avoid strong 
BRDF effects in the nadir line data. Second, a day with a cloud 
less sky is required in order to have a stable solar irradiation. A 
solar zenith angle of 30°-40° results in optimal illumination. 
For standard photogrammetric projects those conditions cannot 
always be fulfilled, but also the radiometric requirements are 
lower. So, since the relative accuracy is much better and since 
the BRDF effects can be corrected to a visually pleasing result, 
the “atmospheric” or “atmospheric + BRDF” options are rec 
ommended as standard settings for data processing in ADS40- 
photogrammetry. 
Integrating the use of measured ground spectra in the reflec 
tance calibration process in XPro (inflight calibration) could 
enhance the absolute accuracy by calibration of the atmospheric 
correction parameters to the actual weather conditions. Also the 
integration of a class-specific BRDF-correction would improve 
the absolute accuracy in case the BRDF effects cannot be 
avoided. 
ACKNOWLEDGEMENTS 
I would like to thank Lauri Markelin and Eija Honkavaara from 
the Finnish Geodetic Institute and Ilkka Korpela from the 
University of Helsinki for methodological discussions. Thanks 
to Ursula KirchgaBner, Uwe Putze, and Marc Schwarzbach 
from the University of Stuttgart for cooperation with the ground 
measurements and for providing Sun-photometer data. 
REFERENCES 
Alvarez, F., Catanzarite, T., Rodriguez-Perez, J.R., and Nairn, 
D., 2010a. Radiometric calibration and evaluation of UltraCam 
X and Xp using portable reflectance targets and spectrometer 
data. Application to extract thematic data from the imagery 
gathered by the National Plan of Arial Orthophotography 
(PNOA). Proc. EuroCOW2010, 10.2.-12.2., Castelldefels, 
Spain. 
Beisl, U., 2006. Absolute spectroradiometric calibration of the 
ADS40 Sensor. In: Int. Arch. Photogramm. Remote Sens., 
Paris, France, Vol. XXXVI, part 1, 5 pp. 
Beisl, U., Telaar, J., and Schonermark, M.v., 2008. 
Atmospheric correction, reflectance calibration and BRDF 
correction for ADS40 image data. In: Int. Arch. Photogramm. 
Remote Sens., Beijing, China, Vol. XXXVII, part B7, pp. 7-12. 
Buhler, Y. A., Huni, A., Kellenberger, T. W„ Itten, K. I., 2009. 
Towards an automated detection of avalanche deposits using 
their directional properties. Proc. 6th EARSeL Workshop on 
Imaging Spectroscopy, Tel Aviv. 
Cramer, M., 2010a. The DGPF-test on digital airborne camera 
evaluation - overview and test design. In: PFG 02-2010, 
http://www.ifp.uni-stuttgart.de/dgpf / PDF/01-PFG02-2010- 
Ueberblick-FinalVersion-20100112.pdf (acc. 18 May 2010). 
Cramer, M., 2010b. http://www.ifp.uni-stuttgart.de/eurosdr/ 
(accessed 18 May 2010). 
Emmolo, D., Orlando, P., Villa, B., 2008. Evaluation of 
capabilities of fuzzy logic classification of different kind of 
data. In: Int. Arch. Photogramm. Remote Sens., Beijing, China, 
Vol. XXXVII, part B7, pp 685-689. 
Fraser, R. S., Ferrare, R. A., Kaufman, Y. J., Markham, B. L., 
and Mattoo, S., 1992. Algorithm for atmospheric corrections of 
aircraft and satellite imagery. Int. J. Rem. Sens., 13(3), pp. 541- 
557. 
González-Piqueras, J., Hernández, D., Felipe, B., Odi, M., 
Belmar, S., Villa, G., and Domenech, E., 2010. Radiometric 
aerial triangulation approach. A case study for the Z/I DMC. 
Proc. EuroCOW2010, 10.2.-12.2., Castelldefels, Spain. 
Green, K., and Lopez, C., 2007. Using Object-Oriented 
Classification of ADS40 Data to Map the Benthic Habitats of 
the State of Texas. Photogramm. Eng. Remote Sens. 73(8), 861 - 
865. 
Honkavaara, E., Arbiol, R., Markelin, L., Martinez, L., Cramer, 
M., Bovet, S., Chandelier, L., Uves, R., Klonus, S., Marshal, P., 
Schlápfer, D., Tabor, M., Thom, C., and Veje, N., 2009. Digital 
airborne photogrammetry — A new tool for quantitative remote 
sensing?—A state-of-the-Art review on radiometric aspects of 
digital photogrammetric images. Remote Sensing 1(3), pp. 577- 
605. 
Kellenberger, T.W., and Nagy, P., 2008. Potential of the 
ADS40 aerial scanner for archaeological prospection in 
Rheinau, Switzerland. In: Int. Arch. Photogramm. Remote 
Sens., Beijing, China, Vol. XXXVII, part B4, pp 1871-1877. 
Markelin, L., Honkavaara, E., Peltoniemi, J., Ahokas, E., 
Kuittinen, R., Hyyppá, J., Suomalainen, J., and Kukko, A., 
2008. Radiometric calibration and characterization of large- 
format digital photogrammetric sensors in a test field. 
Photogramm. Eng. Remote Sens. 74 (12), pp. 1487-1500. 
Markelin, L., Honkavaara, E., Beisl, U., Korpela, I., 2010. 
Validation of the radiometric processing chain of the Leica 
ADS40 airborne photogrammetric sensor. ISPRS TC VII 
Symposium: 100 Years ISPRS - Advancing Remote Sensing 
Science, July 5-7, Vienna, Austria. 
Molina, S., Villa, G., Serrano, C., Valdeperez, M., and 
Domenech, E., 2010. A polynomial approach for radiometric 
aerial triangulation. Proc. EuroCOW2010, 10.2.-12.2., 
Castelldefels, Spain. 
Ryan, R. E., and Pagnutti, M., 2009. Enhanced absolute and 
relative radiometric calibration for digital aerial cameras. Proc. 
Photogrammetric Week 2009, Stuttgart, Germany. 
Schonermark, M., 2010. Status report about the evaluation of 
the radiometric properties of digital photogrammetric airborne 
cameras, 2010. In: PFG 02-2010, http://www.ifp.uni-stuttgart. 
de/dgpf7PDF/05-PFG-02-2010-RadiometrieKalibrierung- 
FinalVersion-20100108.pdf (accessed 18 May 2010) 
Waser, L.T., Eisenbeiss, H., Kuechler, M., and Baltsavias, E., 
2008. Potential and limits of airborne remote sensing data for 
extraction of fractional canopy cover and forest stands and 
detection of tree species. In: Int. Arch. Photogramm. Remote 
Sens., Beijing, China, Vol. XXXVII, part B8, pp 1405-1411. 
Waser, L.T., Klonus, S., Ehlers, M., Küchler, M., and Jung, 
Andras, 2010. Potential of digital sensors for land cover and 
tree species classifications - a case study in the framework of 
the DGPF-project. In: PFG 02-2010, http://www.ifp.uni- 
stuttgart.de/dgpf/PDF/06-PFG-02-2010-RadiometrieKlassifi 
zierung-FinalVersion-20100112.pdf (accessed 18 May 2010).