987 
RIGOROUS PHOTOGRAMMETRIC PROCESSING OF HIRISE STEREO IMAGES 
FOR MARS TOPOGRAPHIC MAPPING 
Ron Li, Ju Won Hwangbo, Yunhang Chen, and Kaichang Di 
Mapping and GIS Laboratory, Department of Civil and Environmental Engineering and Geodetic Science, The Ohio 
State University, 470 Hitchcock Hall, 2070 Neil Avenue, Columbus, OH 43210-1275 - 
(li.282, hwangbo.2, chen.1256, di.2)@osu.edu 
Commission IV, WG IV/7 
KEY WORDS: Digital Photogrammetry, Sensor Models, Bundle Adjustment, Mars Topographic Mapping, High-resolution 
Imaging, Matching, Extraterrestrial Remote Sensing 
ABSTRACT: 
High-resolution (submeter) orbital imagers opened possibilities for Mars topographic mapping with unprecedented precision. While 
the typical sensor model for other Martian orbiters has been the linear array CCD, HiRISE is based on a more complicated structure 
involving combination of 14 separate linear array CCDs. To take full advantage of this high-resolution capability without 
compromising imaging geometry, we developed a rigorous photogrammetric model for HiRISE stereo image processing. Second- 
order polynomials are used to model the change in EO parameters over time. A coarse-to-fme hierarchical matching approach was 
developed and its performance is evaluated based on manually generated tie points for a test area at the Mars Exploration Rover 
Spirit landing site. We then performed bundle adjustment for improving image pointing data using 500 tie points selected from a set 
of matched interest points. Finally, we created a 1-m-resolution Digital Elevation Model (DEM) and compared the DEM with a DEM 
from the U.S. Geological Survey. 
1. INTRODUCTION 
High-precision topographic information is critical to exploration 
of the Martian surface. Topographic information can be derived 
from both orbital (satellite) and ground (lander/rover) data. The 
availability of HiRISE (High Resolution Imaging Science 
Experiment) stereo images has made great progress in high- 
resolution imaging and topographic and morphological 
information derivation for Mars surface exploration (McEwen 
et al., 2007). To take advantage of this new technology, we have 
developed a rigorous photogrammetric model for HiRISE stereo 
image processing, and compared our result (DEM) with that 
from the USGS, whose method was to pre-process the images to 
remove the optical distortion so that a “generic” sensor model 
could be used (Kirk, 2007. Our approach consists of image 
processing/matching and bundle adjustment. For image 
processing, radiometric enhancement was conducted to remove 
systematic noise in the raw images. Then automatic hierarchical 
matching was performed. Bundle adjustment aimed at removing 
the inconsistencies between HiRISE stereo images by adjusting 
their EO parameters based on the rigorous stereo model (Li et 
al., 2007, 2008). 
2. RIGOROUS MODELING OF HIRISE STEREO DATA 
2.1 HiRISE Imaging Geometry 
HiRISE is a push-broom imaging sensor with 14 CCDs (10 red, 
2 blue-green and 2 NIR). Each CCD consists of a block of 2048 
pixels in the across-track direction and 128 pixels in the along- 
track direction. Ten CCDs covering the red spectrum (700 nm) 
are located in the middle (Figure 1, Delamere et al., 2003; 
McEwen et al., 2007). 
REDO 
TDI line motion 
| RED2 
IR10 
IR11 
RED4 
RED6 
REDS 
RED! 
R-ED3 1 I REDS | IREIT 
RED9 
BG12 
■Y * 1 Pro 
,-Track) ^ 
BG13 I 
Projected HiRISE optical axis frame 
(Cross-Track) 
(Down-Track) 
Figure 1. HiRISE CCD layout (after McEwen et al, 2007) 
In the cross-track direction, average overlap width between 
adjacent CCDs is about 48 pixels. However, the alignment of 
CCDs involves small shifts and rotations with regarding to the 
HiRISE optical axis. After excluding overlapping pixels, 
HiRISE can generate images with a swath of up to 20,264 pixels 
(cross-track) and a 30 cm/pixel resolution at a 300 km altitude 
(Delamere et al., 2003; McEwen et al, 2007). At such a high 
resolution, the IFOV (instantaneous field-of-view) is extremely 
small and, as result, the ground track speed becomes very fast. 
To improve the signal strength of “fast-moving” objects and to 
increase the exposure time, Time Delay Integration (TDI) 
technology has been incorporated in the instrument. As the 
MRO (Mars Reconnaissance Orbiter) spacecraft moves above 
the surface of Mars, TDI integrates the signal as it passes across 
the CCD detector by shifting the accumulated signal into the 
next row (line) of the CCD at the same rate as the image moves 
(line rate of 13000 lines/sec = 1 line every 76 microsecond). 
Signals in each TDI block are transferred from line to line at 
ground track speed. A single pixel is formed by accumulating 
signals from the TDI block. HiRISE can use 8, 32, 64 or 128 
TDI stages to match scene radiance to the CCD full well 
capacity. According to the HiRISE instrument kernel (Semenov, 
2007), the observation time of a single pixel is defined as the