Jenoptik VARIOSCAN high resolution Series Manual page 9

Technical Description
The vertical scanner builds up the complete image from the individual
lines. 240 lines can be captured at an image refresh rate of 1.0 Hz.
VARIOSCAN high resolution can also be operated with the following
resolutions (pixel x lines):
360 x 200
360 x 100
360 x 50.
The image information delivered by the scanner is focused onto the
detector through the aspheric imaging optics. The focal length of the
optics is 35 mm, its aperture is f :1. For focusing onto different object
distances, the imaging optics is moved axially covering a range from
0.2 m to infinity.
After every scanned image a reference source (chopper) is moved into
the optical path, and its temperature measured by a thermocouple. On-
line temperature measurement is made possible by comparing the the
radiation intensity of object and chopper.
Between imaging optics and detector, a filter wheel is located. The
wheel contains stops of different diameters that can be rotated into the
optical path at higher temperatures.
The employed object-side scanning method allows the use of an
electro-optical zoom function. This is achieved by varying the oscillation
amplitudes of the scanner reflectors. The maximum zoom possible is
6x.
On the Model 3021, MCT detectors are used having an edge length of
50 x 50 µm. The detectors are cooled by liquid nitrogen.
The metal Dewar vessels used have a hold time of 10 hours.
The Model 3021-ST works with an integrated Stirling cooler.
On the Model 3022, an MCT detector having an edge length of
100 x 100 µm is used. These detectors are cooled by a three-stage
thermoelectrical cooling system. The output signal of the detector is
amplified and digitised, and transferred for further processing to the
PC-104 module.
The implemented control software controls all camera functions (see
Description of control software, Section 8).
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