International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XXXIX-B4, 2012 
XXII ISPRS Congress, 25 August — 01 September 2012, Melbourne, Australia 
The differences may be caused by the possible errors in the 
registration of the two data sets and the possible errors in the 
SELENE laser altimeter data and the Chang’E-1 data. 
  
  
Sinus Iridium Average Max Min Stdv 
(m) (m) (m) (m) 
Track 1 Before 181.05 1520.7 7.32 219.55 
After 51.88 1207.45 1.67 218.95 
Track 2 Before 157.98 679.44 6.25 109.8 
After 22.51 455.65 1.56 109.75 
Whole Before 160 1700 = 150 
area After 10 1520 — 145 
  
  
  
  
  
  
  
  
Table 2. Statistical data for each track and the whole area of 2D 
grey-scale images at Sinus Iridium area before and after Least 
Squares Matching 
3.3.2 Experiments at the Apollo 15 Landing Site Area 
At the Apollo 15 landing site area, two DEMs were first 
interpolated using the Chang’E-1 laser altimetry data and 
SELENE laser altimeter data with the same resolution 1200 m 
(see Figure 6), whose unit is the same with the Sinus Iridium 
arca. Figure 7 shows the registered original Chang’E-1 and 
SELENE laser altimetry data directly overlaid on the Chang’E- 
1 images (backward images) at the Apollo 15 landing site, 
respectively. Figure 8 shows the 2D grey-scale images of the 
DEMs which are used to identify the conjugate areas on the two 
images. There are totally six conjugate points chosen at this 
landing site for further surface matching. The main mountain 
peaks and typical terrain features were carefully selected 
manually and evenly distributed in the study area. Similar to the 
Sinus Iridium areca, a seven parameter transformation was 
conducted to match the Chang’E-1 DEM to the SELENE DEM 
using the conjugate points. 
8 8828883884 
1800 
Hg 
dtésggéééé 
  
Figure 6. Interpolated DEM with the same resolution of 1200 m 
using Chang’E-1 and SELENE laser altimetry data at the 
Apollo 15 landing site area, respectively. 
     
(b) 
Figure 7. The registered Chang’E-1 (a) and SELENE laser 
altimetry data (b) directly overlaid on the Chang’E-1 images 
(backward images) at the Apollo 15 landing site, respectively 
Hoh: 220.11 Hoh : 2.63108 
   
Low : -2826.23 Low : -2,54771 
(a) NC 
Figure 8. The 2D grey-scale images from Chang’E-1 laser 
altimetry data (a) and SELENE laser altimetry data (b) with the 
same 360-m resolution 
Table 3 also shows the obtained transformation parameters 
between the Chang’E-1 DEM and the SELENE DEM, which 
indicate the differences in the positional and orientation 
components between these two data sets. For the Apollo 15 
landing site area, there is about 288 m offset between these two 
data sets in the horizontal direction, and the SELENE laser 
altimeter data is higher than the Chang’E-1 laser altimeter data 
by about 150 m. The deviations in rotations between these two 
data sets are very small, which show the consistent results with 
our recent study (Wu et. al, 2011). The scale factor is 
approximately 1, which means there is very small differences 
between these two models for scale aspect. 
  
Name Apollo 15 landing site 
Value 
  
Scale 1.00101 
AX (longitude, degree) -0.00627942 (-190m) 
AY (latitude, degree) -0.00716208 (-217m) 
  
AZ(altitude) 148.526 m 
^ (p (arc) 0.0083 
A €) (arc) -0.0024 
A K (arc) 0.0015 
  
  
  
Table 3. Transformation parameters between Chang’E-1 
and SELENE laser altimeter data at the Apollo 15 
Landing Site area 
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