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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B7. Beijing 2008 
• Data availability : The existence of various data sets from 
spacebome to airborne sensors ,which are acquired in 
different time intervals ,and ground measurements ,which 
help in the data processing ,information fusion ,and 
validation of the final results . 
3. DATA SOURCES 
Remote sensing techniques are commonly used to determine 
glacier surface displacements. These techniques utilize microwave 
data and optical imagery .The focus of the present study is to use 
multi-temporal optical satellite imagery and aerial photographs .In 
order to measure surface displacement from multi-temporal 
imagery, the following conditions must be met: 
• Surface features have to be detectable in at least two of the 
multi-temporal optical data sets in order to track them. 
• The multi-temporal data sets have to be accurately 
coregistered. 
• The spatial resolution of the image has to be finer than the 
displacements. 
In this research ,High resolution satellite imagery including 
Quickbird image with 2,5 m spatial resolution , SPOT 5 
panchromatic image (2.5m) acquired at the end of September are 
utilized along with six aerial photoghraphs of 1:40000 scale. 
4. METHODOLOGY 
If the two images are correlated, the resulting offsets in the image 
lines and columns are the sums of the contributions from 
misregistration, topography, orbits, and attitude as well as the 
glacier-dynamics signal. To obtain a valid measurement, we must 
remove all the contributions except the glacier flow (E. Berthier et 
al:’ 2005). 
4.1 Optical satellite imagery 
In order to measure glacier displacement map ,Spot 5 and multi- 
spectral Quickbird images respectively acquired at September 
2003 and 2005 from study site are used .In the first step,for 
accurate change detection ,images must be radiometricllay 
normalized. Afterwards,performing image to image co 
registration is a necessary step to provide a solid base for image 
matching and change detection analysis. 
Figure. 1: Flowchart of the methodology followed to measure the 
surface displacements 
4.1.1. Radiometric normalization 
The first step of using multi-temporal satellite imagery in this 
procedure is to perform normalization so that they share the 
similar radiometry ,one of the conditions for an accurate 
displacement computation. 
Ground reflectance determination from satellite imagery requires, 
among other things, an atmospheric correction algorithm and the 
associated atmospheric properties at the time of image acquisition. 
For most historical satellite scenes such data are not available and 
even for planned acquisitions or they may be difficult to obtain.In 
this case a relative normalization using the radiometric 
information must be performed .In this work ,images were first 
normalized by ENVI4.4 software using IAR reflectance method. 
Thereafter accurate relative normalization procedure was 
conducted utilizing time-invariant objects such as shelter for 
climbing groups. 
4.1.2. Co-registration of multi-temporal satellite imagery 
A critical requirement in change detection applications is that 
multitemporal images must be co-registered accurately. In this 
study, an image to image co-registration was carried out with a 
sub-pixel resulting RMSE of about 0.039 pixel. 
4.2 Airborne photographs 
4.2.1 DEM & ortho-photo generation 
As mentioned earlier ,six aerial photos are used in this research. In 
order to generate DEM, firstly ground control points for 
photogrametric processing were acquired through a Bundle Block 
Adjustments Aerial Triangulation. The DEM was produced using 
VirtozouNT photogrammetric software. Thereafter ortho image 
mosaic of the entire area was generated.