VIA Technologies EPIA SN-Series Specifications download pdf (Page 42)

FASTER

4.3 FASTER Cameras Geometry

In order to define the acquisition system geometry, some considerations regarding the

different layout possibilities shown in Figure 24 and Figure 25 must be made:

 The upper right layout of Figure 24 shows an array matrix of 2 adjacent

detectors sharing the same lens assembly; this solution was used when only

small sized devices were available, so an array of detectors can be used on the

same focal plane in combination with a standard photographic lens (36 x 24

mm format) or a large format lens (60 x 40 mm); to take advantage of modern

full format digital sensors a custom lens must be made making this solution

expensive;

 The upper left layout of Figure 24 shows a 3 cameras system arranged to

obtain a very large swath width on the ground; image geometry must be

carefully taken into account because of the tilt angle used between the two

lateral cameras, in addiction shadows effects may be relevant and cause

problem during orthophoto reconstruction; this system is not suitable for

remote sensing purposes because others bands may be difficult to add;

 In the bottom left layout of Figure 24 a 4 cameras system, using 4 different

optical heads, is shown; such a system offers the same advantages of a two

separate cameras system in terms of swath width but with a larger image side

in the along-track direction, reducing the total number of images used to cover

the same target area and thus the mosaicing time;

 The bottom right layout of Figure 24 shows an “oblique photography” system

made up by five separate cameras; these system are suitable for 3D

reconstruction but cannot be used for remote sensing purposes;

 The layout shown in Figure 25 represents a pushbroom line scanner; this

solution implies the use of a very expensive custom focal plane assembly; it

must be used from a very stable platform in order to obtain a correct image

reconstruction (lines have to be merged together in order to generate the final

image which is a process that requires an high computational load); it is

suitable for very large areas because reduces the mosaicing operations;

In order to maintain multispectral capabilities (offering the red, green, blue and nIR

bands) but maintaining a large swath width on the ground, thus reducing the total flight

time, a three cameras system has been selected and it is shown in Figure 27.

1 2 ... 37 38 39 40 41 42 43 44 45 46 47 ... 143 144

No comments

VIA Technologies EPIA SN-Series Specifications Page 42