International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
Since this sensor is a digital three-line scanner with sensing
capabilities for nadir, fore and aft looks, already three different
views of the target area exist. This forms an excellent basis for
the calculation of further views for the lenticular foil vision (cf.
Chapter 4. Data Processing).
2. INPUT DATA
2.1 Topographic Base
As the major source of topographic information served the sheet
"Mars" of the multi-lingual series of ICA Maps of the Planets
and their Moons (Mars Map, 1999) plus other material out of
which this maps has been compiled.
2.2 Remote Sensing Imagery
The imagery used has been acquired since January 2004.
The post-processing carried out at DLR Berlin-Adlershof
includes in a first step the rectification of the single image strips
based on DGPS and INS data. In the second step the image
strips have been mosaiced to the whole image. In the case of
HRSC it means, that the majority of the pixels displays
synthetic radiometric values, calculated for the overlap areas of
the strips which amount to nearly 50 percent across track.
Parameter Valua
THX 7808B
7 um x 7 um
detector type
sensor pixel size
field of view per pixel (IFOV) 8.25 arcsec
active pixels per ccd line 9 sensors a 5184
radiometric resolution 8 bit
spectral filters 5 panchromatic, 4 colour
nadir, 2 stereo, 2 photometric 675490 nm
stereo angle of stereo channel +18.9°
stereo angle of photometric
channel 2:12.09"
440245 nm, 530445 nm,
Blue, Green, Red, Near Infrared | 750420 nm, 970+45 nm
stereo angle of Red, NIR £15.9°
sterco angle of Blue, Green +33°
maximum scan rate 450 lines/s
Table 1. Technical data of HRSC Mars Camera, in part based
on (Hauber, E., Jaumann, R,, Wewel, F., Gwinner, K., Neukum,
G., Siupetzky, H., 2000).
The original data, with their excellent ground resolution, have
been resampled to an appropriate size which saites to the
respective map product. The excellent radiometric properties of
the imagery proved ideal for a true-colour depiction of this
high-relief terrain.
3. MAP DESIGN
In order to reach an optimum balance between the area to be
covered, the final geometric resolution of the remotely sensed
image data, and the available sizes of lenticular foils, the final
formats of the actual map areas had to be chosen.
Due to the fact that an excellent image data material was at our
disposal, already at an early stage the decision was made that
the final product should be a so-called CIL (combined image-
line) map, thus combining the advantages of a sort of photo-
realistic depiction of the terrain in true-3D and the abstracted
cartographic information (Buchroithner, M. F., Kostka, R,
1997). For further remarks on the lettering and other
cartographic aspects see Chapter 5.
Based on the assessment of tentative map layouts, the final map
designs with the title on the top, legend and overview map had
to be determined. Some peculiarities in comparison with
“normal” two-dimensional maps had to be considered. Since the
lenticular foil will cover the whole map format including the
margin special attention had to be paid to the legibility of all the
collateral map information (imprint, legend, title, overview
map). This process is determined by the initial image data
resolution, the print resolution and the resolution of the human
perception capability and led to a final map scales. The actual
layout of the maps is slightly differing.
4. DATA PROCESSING
4.1 Geometric Modelling
Initially, some basic remarks concerning the geometry of
lenticular foil true-3D maps shall be made. With reference to
the renowned textbook by Okoshil975 (Okoshi, T., 1976) and
the paper by Buchroithner and Waelder (these proceedings;
(Waelder, O., Buchroithner, M. F., 2003)), the ray geometry
implied by the tunnel shape of the individual lenses can be
derived from the Figures 1 and 2.
In contrast to classical parallax stereoscopy, for a high-quality
true-3D representation based on lenticular technology, a number
of stereomates significantly higher than two had to be
calculated. In a way simulating an east-west airplane overflight
a minimum of seven convergent views was generated. This is a
prerequisite for a "smooth" viewing of a lenticular scene from
different east-west directions. Further research in the
optimisation of the lenticular techniques is planned.
y Lenticular Foil
Figure 1. Scheme of lenticular foil principle.
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