THE USE OF EXISTING GLOBAL ELEVATION DATASET FOR ABSOLUTE 
   
ORIENTATION OF HIGH RESOLUTION IMAGE WITHOUT GCPS 
J. Jeong, T. Kim * 
Department of Geoinformatic Engineering, Inha University, 253 Yonghyun-Dong, Namgu, Incheon Korea 
jaehoon@inha.edu, tezid@inha.ac.kr 
KEY WORDS: DEM matching, global elevation data, High resolution satellite image, Absolute orientation, Sensor model 
ABSTRACT: 
For precise mapping using high resolution satellite images, various ways to eliminate the need of ground control points have been 
proposed. DEM matching, a technique to match two different surfaces by adjusting their position and attitude, is also one way of 
them. Our previous study demonstrated that DEM matching can be used for bias compensation of rigorous pushbroom sensor models. 
In this paper, we exploit the DEM matching technique further using existing global elevation dataset for absolute orientation of high 
resolution satellite image without ground control points. In particular, we investigated how the existing global DEM available 
worldwide can substitute ground control points when DEM matching is applied to linear pushbroom imagery. We used Spot-5 HRG 
with 2.5m ground sampling distance(GSD) as high resolution satellite images and used SRTM-derived DEMs(DTEDs) with gird 
spacing of 30m and 90m as existing elevation dataset. We firstly established relative orientation and generated a relative DEM 
without use of ground control points. DEM matching was then applied between the relative DEM and the DTED. We applied DEM 
matching based on linear pushbroom images. Through DEM matching, accuracy of about 2 GSD or better could be achieved with in 
the horizontal and in the vertical direction, respectively. We confirmed automatic DEM matching processing can be accomplished 
for absolute orientation of pushbroom image and as results, absolute DEM can be achieved from relative DEM. We tested the 
applicability of 90m existing global dataset for DEM matching. Our experimental results showed the potential of existing DEM for 
precise mapping without ground control points. This is very encouraging in terms of applicability of the existing global elevation 
data. This paper will contribute to understanding of DEM matching for linear pushbroom images and of solution to precise mapping 
without ground control points. 
1. INTRODUCTION 
Precise mapping is one of the fundamental requirements for 
satellite images. As satellite sensors now provide very high 
resolution comparable to aerial images, more active are 
investigations on achieving high precision geometric 
information from satellite images. However, due to insufficient 
accuracy of the platform's ephemeris and attitude information, a 
large scale mapping still requires ground control points(GCPs). 
To avoid time-consuming and expensive GCPs measurements, 
various ways to eliminate the need of GCPs have been proposed. 
Investigation to fully employ existing control points was 
implemented for automated generation of control points for new 
satellite images(Kim and Im, 2003). Previously ortho-rectified 
satellite images and height information from a suitable existing 
elevation dataset was used to replace the need of 
GCPs(Jacobsen, 2005) and similar approaches have been 
carried out by others(Muller et al., 2007; Gianinetto and Scaioni, 
2008). More recently, the use of radar data was investigated to 
solve the necessary improvements of geometric accuracy of 
optical data such as IKONOS and ALOS-PRISM(Reinartz et al. 
2011). We try here to examine DEM matching using existing 
global elevation data. If the existing global elevation data can 
replace GCPs through DEM matching, our proposal could be an 
efficient solution to the precise mapping using satellite image 
without GCPs. 
DEM matching is a technique to match two different surfaces 
by adjusting their position and attitude. It was originally 
proposed for absolute orientation of perspective 
images(Rosenholm and Torlegard, 1988; Ebner and Strunz, 
, 
  
x Corresponding author: T. Kim (tezid@inha.ac.kr) 
1988) and has been exploited further through several 
investigations(Ebner and Ohlhof, 1994; Sim and Park, 2002; 
Gruen and Akca, 2005). DEM matching for pushbroom image 
was also proposed(Ebner et al, 1991). In our previous 
investigation, we validated DEM matching could be used for 
bias compensation of pushbroom satellite images(Kim and 
Jeong, 2011). We applied DEM matching for linear pushbroom 
image with rigorous sensor models and showed that absolute 
orientation of pushbroom image was established from the DEM 
matching. 
This paper attempts to exploit DEM matching technique 
further by using automated grid point selection and by using 
different elevation dataset to compare the results of absolute 
orientation. In our previous study, we selected grid points for 
DEM matching manually and removed outliers based on visual 
inspection. We used elevation dataset at 30 spacing for DEM 
matching. In this paper, we will check whether DEM matching 
can be fully automated including grid point selection. We will 
also use the publically available elevation dataset(DTED at 90m 
spacing) and check whether this dataset can be used for precise 
mapping without GCPs. Firstly, we will briefly review our 
previous study and then discuss how to improve the previous 
study here. 
2. ABSOLUTE ORIENTATION OF PUSHBROOM 
IMAGES FROM DEM MATCHING 
In previous investigation, we examined DEM matching for 
absolute orientation of pushbroom images without GCPs. We