metric 
ight- 
raint 
letry 
t each 
erlying 
lies on 
ilizes 
makes 
| as 
ment 
hrough 
There 
y. lits 
. The 
t space 
space. 
Ise. 
sht-line 
on of a 
trains à 
and the 
nted as 
> image 
In this 
f frame 
Devin Kelley 
  
2. BACKGROUND 
2.1. Linear array scanner imagery 
With the increased use of digital photogrammetry, there are motivations to use digital cameras to facilitate the 
automation of photogrammetric tasks. To attain the same resolution as aerial frame photography, 20K x 20K 2-D 
digital array sensors would be necessary. However, at this time, the highest resolution commercially available is 4K X 
4K. Linear array scanners simulate 2-D images by using a 1-D array of sensors operating with an open shutter on a 
moving platform. 
Linear array scanners have one or more 1-D arrays of CCD sensors in the image plane. The electromagnetic energy 
incident upon these sensors at a given time will constitute an image. Movement of the platform and/or rotation of the 
lens configuration will enable successive coverage of different areas on the ground. A scene is defined as a sequence of 
linear array scanner images. Depending on the number of 1D-arrays, the scanning direction and the relation of the 
sensor with the flight direction, one differentiates between three-line, pushbroom and panoramic linear array scanners 
(see figures 1 and 2). 
  
  
      
   
    
   
y X x 
Perspective Center 
C3 
Perspective Center 
a. Frame Camera b. Pushbroom Scanner 
Figure 1: Perspective geometry of frame cameras (a) and pushbroom scanners (b). 
cut Direct y Scan Flight 
Flight Direction Angle Direction 
Um 
joe Ele 
X t rtu 
l^ 
i 
i 
i 
1 
Perspecti 
Center : 
: 
Y 
a. Three-line Scanner b. Panoramic Linear Array Scanner 
Figure 2: Perspective geometry of three-line scanners (a) and panoramic linear array scanners (b). 
Previous research at The Ohio State University has focused on modeling the perspective geometry of linear array 
Scanners (Habib and Beshah, 1998). The collinearity model used for frame imagery has been modified in such a way 
that it is also valid for pushbroom, three-line and panoramic linear array scanners. This model accommodates the most 
&neral scenario for linear array scanners- panoramic linear array scanners. Collinearity models for the other scanner 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part Bl. Amsterdam 2000. 179