nned aerial
ect georef-
hotogram-
grammetry
m.
is, Institute
rland.
M., 2009.
Vs. DGPF
its impact
)09, Dieter
nted mon-
video im-
of the Pho-
1 Sciences,
229-1236.
les (UAVs)
Archives of
formation
[. Part Bl,
11. Perfor-
tion. Inter-
ensing and
AV-g 2011,
cs, Zurich,
cation and
Rhombos-
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B7, 2012
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia
AERIAL TERRAIN MAPPING USING UNMANNED AERIAL VEHICLE APPROACH
K. N. Tahar
Dept. of Surveying Science & Geomatics, Faculty of Architecture, Planning & Surveying
Universiti Teknologi MARA,40450 Shah Alam, Selangor, Malaysia - nizamtahar @ gmail.com
KEY WORDS: Mapping, Analysis, Camera, Accuracy, Aerial, Photogrammetry
ABSTRACT:
This paper looks into the latest achievement in the low-cost Unmanned Aerial Vehicle (UAV) technology in their capacity to
map the semi-development areas. The objectives of this study are to establish a new methodology or a new algorithm in image
registration during interior orientation process and to determine the accuracy of the photogrammetric products by using UAV
images. Recently, UAV technology has been used in several applications such as mapping, agriculture and surveillance. The aim
of this study is to scrutinize the usage of UAV to map the semi-development areas. The performance of the low cost UAV
mapping study was established on a study area with two image processing methods so that the results could be comparable. A
non-metric camera was attached at the bottom of UAV and it was used to capture images at both sites after it went through
several calibration steps. Calibration processes were carried out to determine focal length, principal distance, radial lens
distortion, tangential lens distortion and affinity. A new method in image registration for a non-metric camera is discussed in this
paper as a part of new methodology of this study. This method used the UAV Global Positioning System (GPS) onboard to
register the UAV image for interior orientation process. Check points were established randomly at both sites using rapid static
Global Positioning System. Ground control points are used for exterior orientation process, and check point is used for accuracy
assessment of photogrammetric product. All acquired images were processed in a photogrammetric software. Two methods of
image registration were applied in this study, namely, GPS onboard registration and ground control point registration. Both
registrations were processed by using photogrammetric software and the result is discussed. Two results were produced in this
study, which are the digital orthophoto and the digital terrain model. These results were analyzed by using the root mean square
errors and mean absolute error to determine the level of accuracy and the precision of photogrammetric products. It can be
concluded that the new method of image registration by using the GPS onboard of the UAV produces medium accuracy result
compared to the method that uses the ground control point. This new method can be used for the medium accuracy requirements.
Unmanned Aerial Vehicle can be used for several applications, which requires a medium accuracy.
1. INTRODUCTION
1.1 Related Works
Unmanned aerial vehicle is extremely potential in mapping
field and provide high data accuracy. There are many types and
designs of UAV that are available in the market. UAV can collect
images from wide range from O — 2000 kilometer of flight
altitudes (UVSIA, 2010). In many countries the aviation
regulation limit the altitude and visibility (line) of sight) is
required to the UAV. UAV also offers the same concept of image
acquisition like manned flight but it does not required onboard
pilot during flight mission. UAV can be deployed rapidly and it
gives high resolution images for spatially limited areas. UAV also
has the potential in surveillance missions (David et al, 2008;
Dingus et al., 2007) and aerial tracking for various purposes and
in a variety of applications. Many studies have investigated the
capabilities of UAV in agricultural mapping using multispectral
Sensor in order to classify the plantation in term of health
condition (Grenzdorffer et al. 2009; Herwitz et al, 2004).
However, the integration between UAV and multispectral
instruments require many modifications due to the payload
limitation and endurance hour of the UAV. UAV has also been
used in urban area mapping by producing a layout map of the
urban area. The layout can be used by many organizations for
strategic planning in the urban area (Jwa and Ozguner, 2007).
This product could be used for city planning to direct sustainable
development in certain area.
Fixed wing UAV can be operated autonomously or under
radio control by operator. In some cases, autonomous flight
control could be less accurate in term of conducting the flight plan
due to the UAV turbulence which is affected by wind direction
(Osborne and Rysdyk, 2005). However, one advantage of
autonomous flight mission is that it can be used for large study
area without any concern of the human eyes' limitation. However,
the local aviation regulations are to be taken in to consideration.
Manual and autonomous flight needs the similar amount of
control, by checking the path conducting, and possible anomalies
in the instrumentation on UAV from the beginning until the end
of flight mission. The safety of UAV relies on the skill of the
operator during flight mission. Unfortunately, manual flight
mission is unable to cover large area due to the limitation of the
human eyes. A fixed wing unit such as cropcam has been
assembled with a complete package for flight mission. It includes
autopilot chip, electronic speed controller (ESC), GPS onboard,
Camera mount, gyro, wireless modem and high resolution camera
