The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B4. Beijing 2008 
Ephemeris Time (ET) when the center of the TDI block is 
exposed. 
be processed together under a uniform rigorous sensor model in 
the bundle adjustment instead of being processed strip by strip. 
The HiRISE instrument kernel provides the calibrated interior 
orientation parameters needed to calculate the pixel view 
direction with respect to the HiRISE frame 
(MRO HIRISE OPTICAL AXIS). In the raw image, the row 
position of each pixel is related to the Ephemeris Time, which 
then determines the position and orientation of the HiRISE 
frame. The CCD ID and the column position are translated into 
the physical position of a pixel in the HiRISE frame. If a pixel 
in CCD i is located at column m, the following equations can be 
used to retrieve the ideal focal plane coordinates. 
u = TDI/2 - 64 - (BIN/2 - 0.5) 
v = (m - 0.5) • BIN - 1024 
x = transxjo + transxjj • v + transx i>2 ■ u 
y = transyj o + transtyj ] • v + transy i 2 • u 
(1) 
r = (x 2 + yV /2 
dr/r =-0.0048509 + (¿-2.41312 ■ 10 ' 7 ) 
+ (r 4 -l.62369- 10 - 13 ) 
xp = x - (dr/r) • x 
YP = y ~ (dr/r) • y 
where u, v = pixel position with respective to CCD center 
TDI = number of TDI elements in the along-track 
direction (8, 32, 64 or 128) 
BIN = binning mode (1,2, 3, 4, 8, or 16) 
m = pixel position in column direction 
x, y = pixel position with respect to HiRISE optical 
axis 
transx i k , transy i k = calibration parameters (k = 0,1,2) 
xp, yp = ideal focal plane coordinates after 
elimination of radial distortion 
2.2 Image Pointing Data 
Exterior Orientation (EO) parameters, which are the positions of 
the camera perspective center and pointing angles at a specific 
time, are provided in SPICE kernels. The EO parameters of 
each image line can be retrieved by interpolating the 
spacecraft’s trajectory and pointing vectors. Previous research 
has shown that the change in EO parameters over short 
trajectories can be well modeled using polynomials (Yoon and 
Shan 2005; Li et al., 2007, 2008). In this research, second-order 
polynomials are used to model this change 
X‘ ( . — a 0 + a x t + a 2 t~ 
Y . = b 0 + b x t + b 2 t 
Z c j. = c 0 +c { t + c 2 t 2 
of, = d 0 + d x t + d 2 t 2 
qfj. =e 0 + e x t + e 2 t 2 
K °i = fo + f\ t + fi r 
(2) 
To apply the above strategy, one reference CCD strip must be 
assigned; this strip can be arbitrarily chosen. Then the offsets 
between other CCD strips and the reference strip are calculated 
by comparing their EO data line by line. The line (row) index of 
the EO polynomials of the reference strip starts from zero. For 
the other non-reference strips, it starts from the offsets. The 
initial value of the EO polynomial coefficients can be estimated 
by least-squares fitting of the line-by-line telemetry EO data. 
Small motions of the spacecraft around its nominal pointing, 
called jitter, will distort the images. This problem was originally 
identified in the Mars Orbiter Camera (MOC) images, but was 
found to be more severe for HiRISE because of HiRISE’s 
higher resolution (Kirk et al., 2007). High-frequency jitter can 
be filtered out by subtracting the best-fitting polynomial from 
the original telemetry HiRISE pointing angle data. For the 
80,000 line image of Gusev Crater that was used in this study, 
Figure 2 shows the extracted jitter on co, <p, k with the horizontal 
axis being the image row index and the vertical axis being the 
jitter magnitude in arc-seconds. An analysis of the extracted 
residuals in the spectral domain does not show any significant 
frequency. Therefore, it would be very difficult to incorporate 
this “jitter” into a mathematical model. 
Figure 2. Residuals after subtracting best fitting polynomial 
from original telemetry EO data 
Topographic effect of orbital jitter needs to be evaluated for 
topographic capability analysis of HiRISE camera. For 
evaluation, a single CCD pixel was projected onto the Martian 
surface using telemetry EO data under the assumption that Mars 
is a sphere with its radius derived from the nearest MOLA point. 
The projected footprint was compared with another projected 
footprint using EO parameters adopted using third-order 
polynomials under the same spherical assumption. A maximum 
difference of 2 meters, corresponding to 7 pixels on image, was 
detected from the comparison in a 20-kilometer track at the 
landing site of Mars Exploration Rover (Spirit). Further 
investigation on jitter will be performed so that its effects can be 
removed or reduced when mapping large areas. 
where A 1 ), Y c il zf) = position of the perspective center of the 
sensor of the i th line (time t) 
a>i, tpi, K t = pointing angles of the i th line 
a 0 , —,/2 = polynomial coefficients 
t = time-dependent image line index number 
Modeled this way, EO parameters can be adjusted by refining 
the 36 polynomial coefficients of the stereo pair. Since all 14 
CCDs are fixed to the HiRISE frame, they share the same 
perspective center and focal plane. Therefore, changes in the 
EO parameters of all 14 CCDs yield one set of polynomial 
coefficients. This critical characteristic significantly reduces the 
complexity of the bundle adjustment of HiRISE stereo images. 
Images simultaneously generated by multiple CCD arrays can 
3. PHOTOGRAMMETRIC PROCESSING OF HIRISE 
STEREO IMAGES 
3.1 Image Matching and Tie Point Generation 
We have developed a coarse-to-fme hierarchical stereo 
matching process (Figure 3). Raw HiRISE images contain 
systematic noise such as offset in the image data numbers (DN), 
dark current, and column-to-column gain variations (Becker, 
2007). In HiRISE EDR (Experiment Data Record) data sets, the 
image acquired by each CCD strip (14 in total) is stored as two 
sub-image strips, each of which is 1024 pixels wide. Brightness 
values of the two sub-image strips may be inconsistent. We 
adjusted brightness values and then combined them together 
into one seamless image with a 2048-pixel wide swath. 
Afterwards, we removed any systematic strip noise. Then, an 
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