723 
A NEW GROUND-BASED STEREO PANORAMIC SCANNING SYSTEM 
R. Li*, L. Yan, K. Di, B. Wu 
Mapping and GIS Laboratory, Dept, of Civil and Env. Eng. and Geodetic Science, The Ohio State University 
470 Hitchcock, 2070 Neil Ave., Columbus, OH 43210-1275, USA - {li.282, yan.351, di.2, wu.573}@osu.edu 
Commission V, WG-V-5 
KEY WORDS: Panoramic Scanning System, Panoramic Camera, Multi-perspective Panorama, Geometric model, 3-D Mapping 
ABSTRACT: 
This paper introduces a linescan-based stereo panoramic scanning system that employs an off-axis camera configuration mode. In 
this mode, the two stereo linescan cameras are mounted off-axis on the horizontal bar of a camera mast, approximately equidistant 
from the rotation axis. Compared to the on-axis mode used in many other linescan-based panoramic scanning systems, the off-axis 
mode enables the system to acquire multi-perspective stereo panoramas that can provide uniform accuracy in all 360° directions at 
each depth. A prototype using a color linear array camera with RGB channels has been developed at the Mapping and GIS 
Laboratory of The Ohio State University. The future version of this system will be a Mobile Panoramic Multi-spectral Scanner 
(MPMS) in which each camera will include multi-spectral channels such as VNIR (Visible and Near Infrared) and SWIR (Short 
Wavelength Infrared). This new system has the potential to be used in future Mars landed missions for the detection and mapping of 
minerals, water and other habitability signatures as well as for support of Earth-based applications. 
1. INTRODUCTION 
Linescan-based panoramic scanning systems are based on 
rotating linear array sensors and recording image lines within a 
cylindrical geometry. One of their major capabilities is quick 
image acquisition of any panoramic scene. Another is the 
acquisition of high-quality images having high resolution and 
homogeneous brightness and contrast throughout the entire 
image. These features make linescan-based panoramic scanning 
systems suitable for applications such as recording landscapes 
and city squares, cultural heritage documentation, and data 
capture for virtual reality applications. Examples of two 
commercially available scanning systems used for these 
purposes are the EYESCAN M3 terrestrial digital panoramic 
camera, which was jointly developed by the German Aerospace 
Center (DLR) and KST Dresden GmbH, and the Sasta Digital 
DRS 5000 camera developed by Spheron PanoCam. 
There are two camera configuration modes applied in 
panoramic scanning systems: the on-axis mode and the off-axis 
mode, designating whether or not the camera’s perspective 
center is designed to be on the rotation axis. The panoramas 
acquired with these two modes are referred to as either single 
center panoramas (on-axis) or multi-perspective panoramas 
(off-axis). Many systems use the on-axis mode such as the 
EYESCAN M3 and the Sasta Digital DRS 5000, and single 
center panoramas have been well researched concerning 
calibration, geometric modelling, and bundle adjustment of the 
data (Schneider and Mass, 2003; 2004; 2005; 2006). Other 
examples of the research and application of these systems 
include visualization and texture mapping (Haala and Kada, 
2005), and data fusion with laser scanners (Scheibe et al., 2004). 
Although they have a simpler geometric model, single-center 
stereo panoramas have a disadvantage in stereo vision, which is 
formed by two cameras rotating around two separate axes; the 
3-D information derived from such two stereo panoramas by 
spatial intersection does not have uniform accuracy in all 360° 
directions, particularly in the baseline direction. As a result, 
more panoramas normally have to be taken in order to avoid 
weak intersection geometries. Otherwise, we can form a vertical 
baseline, but this would cause difficulties in stereoscopic 
viewing. This may limit the potential of on-axis panoramic 
scanning systems in situations where constraints (e.g., vertical 
height) would not allow a vertical stereo configuration, for 
example, for a space exploration vehicle. 
On the other hand, while multi-perspective (off axis) panoramas 
have a more complicated geometric model, they are able to 
overcome the problem of nonuniform accuracy in different 
directions. Furthermore, the off-axis mode offers more 
flexibility in system configuration. 
The panoramic camera system presented is a Mobile Panoramic 
Multi-spectral Scanner (MPMS) that employs the off-axis 
camera configuration mode. The system can be mounted on 
either a manned or unmanned vehicle. The designed system will 
include two stereo multi-spectral cameras, each having 10 
vertical linear array CCDs representing visible (RGB), infrared 
(IR) and other multi-spectral channels. With only one sweep, 
MPMS can acquire all the channels of stereo panoramic images 
to fully characterize the surrounding environment. This system 
can be used for environmental monitoring, homeland security, 
transportation, and landed planetary missions. 
The system introduced in this paper is a prototype of MPMS 
that uses a color linear array camera with RGB channels. A 
future version will include multi-spectral channels. In the 
following section, the stereo camera configuration and 
hardware integration of the prototype are described. Section 3 
addresses the geometric model and stereo geometry of multi 
perspective panoramas. In Section 4, sample panoramas 
* Corresponding author,