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complete sensor model), and a constraint equation is used for
points that are known to lie on the same plane. The parameters
of the sensor model are estimated by minimizing the errors (e.g.
least squares). Other methods of calibration that use extracted
breaklines and points have also been successfully implemented
(Habib et al., 2010)
Quasi-rigorous Calibration Methods
Quasi-rigorous geometric correction methods are very similar
to the rigorous methods in terms of their use of planar and
other features as tie features towards geometric processing of
data. However, these methods do not have access to the actual
sensor model, or all the parameters involved in the sensor
model. These methods therefore use a generic sensor model
substituting proprietary or unknown sensor parameters with
generic sensor parameters. Examples of a generic sensor model
include the Universal Lidar Error Model (ULEM, Rodarmel
et al., 2015), now renamed as the Generic Point Cloud Model
(NGA, 2015). Some methods also use a limited set of parameters
(e.g. using trajectory information, but not the range). However,
the geometric correction process is the same as the rigorous
methods, i.e. these methods also use planar patches, extracted
planar features or combine extracted planar features to make
measurements on derived features such as breaklines and
points (Habib et al., 2010).
Recommendations for Further Research
The Sensor Model based calibration methods are essential for
the success of error propagation models that estimate the error
present in the lidar data point cloud. The WG recommends that
•
The possibility of expressing error in terms of generic
sensor models be investigated further.
•
Isolating the contribution of generic subsystems towards
the total error budget be studied further. In particular,
the errors introduced in the point cloud data due to er-
rors in sensor trajectory must be further investigated
References
Habib A, Kersting A. P., Bang K. I., and D. C. Lee. 2010.
“Alternative Methodologies for the Internal Quality
Control of Parallel LiDAR Strips,” in IEEE Transactions
on Geoscience and Remote Sensing, vol. 48, no. 1, pp. 221-
236, Jan. 2010.
doi: 10.1109/TGRS.2009.2026424
Heidemann, H. K., 2014, Lidar base specification version
1.2, U.S. Geological Survey Techniques and Methods,
Book 11, Chapter. B4, 63 p.
Rodarmel, C.; Lee, M; Gilbert, J.; Wilkinson, B.; Thiess, H.;
Dolloff, J; O’Neill, C; “The Universal Lidar Error Model”.
Photogrammetric Engineering and Remote Sensing, July
2015, Volume 81, Issue 7; pp. 543-556.
National Geospatial-Intelligence Agency, 2015, The Generic
Point-cloud Model (GPM): Implementation and Exploita-
tion, NSG Standards Documents. Available online:
.
Acknowledgement
This document represents a collaboration between indus-
try and government partners through a US Geological Sur-
vey (USGS)/ASPRS Lidar Data Quality Working Group, or
sometime referred to as the “ASPRS Lidar Cal/Val Working
Group”. ASPRS and its Lidar Division greatly appreciate the
collaboration and effort provided by the community to com-
plete this guidelines document. Any comments, questions or
suggestions related to these guidelines, associated software,
or associated research can be addressed through the ASPRS
Lidar Division,
.
The ASPRS would also like to recognize the USGS for de-
veloping and providing the software executable, a Python
version of the software for technical decomposition and use,
and the associated software documentation that supports the
process defined in this guideline.
The ASPRS would like to provide a special acknowledgement
and thank you to the Lidar Division and its Airborne Lidar
committee, the Lidar community, and to the US Geological
Survey (USGS)/ASPRS Lidar Data Quality Working Group
which allowed these guidelines and associated software to
be made available. ASPRS provides specific recognition for
the original members and key contributors to this working
group: Mr. Greg Stensaas, Dr. Aparajithan Sampath, Mr.
Karl Heidmann Dr. Jason Stoker, Dr. Ayman Habib, Dr. Val-
erie Brooks, Mr. Matt Bethel and to all those who support
this long term effort.
