User Manual for the Thermographic System VarioCAM
®
hr head
3. Technical Description
6
© InfraTec GmbH 2012
User Manual
Thermographic system of resolution (640 x 480) pixels
lens
focal length (mm)
min. focus (m)
IFOV (mrad)
FOV (°)
wide-angle lens
12.5
0,2
2.0
(65 x 51)
standard lens
30
0,3
0.8
(30 x 23)
telephoto lens 1
50
2,0
0.5
(18 x 14)
telephoto lens 2
75
2,0
0.3
(12 x 9)
telephoto lens 3
130
5,0
0.2
(7 x 5)
close-up lens
focal length (mm)
focus (mm)
field of view (mm²)
resolution (
μ
m)
close-up 0.17x
for 30
150
(80 x 60)
125
close-up 0.5x
for 30
50
(27 x 20)
42
microscopic lens 1.0x
-
50
(16 x 12)
25
Detector
The VarioCAM
®
hr head has an uncooled microbolometer FPA detector (uncooled
F
ocal
P
lane
A
rray).
The detector is thermally stabilised with high precision using a Peltier element and is thus independent of
the ambient temperature.
The various elements of the detector are microscopically minute thin-film resistors on wafer-thin
membranes, which are arranged cantilevered a few micrometers above the silicon read-out circuit. The
thermal radiation of the scene is imaged by the lens of the thermographic system on these detector
elements and absorbed by them. The temperature change of the detector elements resulting therefrom
yields electronically evaluable signals which can be read out line-wise and column-wise by a read-out
circuit.
Applying an uncooled detector guarantees quick availability of the camera function after switching it on
(start-up time < 60 seconds) and long service life (MTTF) in permanent use.
Detector electronics
The detector electronics supplies the BIAS voltages required for detector operation and further control
signals, and it takes care of the pre-processing and digitalisation of the analog video output signal from
the detector.
Image processing electronics
Real-time image processing with the following essential functions (depending on the equipment) is
implemenmted with the help of an
FPGA
(
F
ield
P
rogrammable
G
ate
A
rray) and an
embedded PC
(modular compact internal PC):
■
Detector electronics interface
■
Gain and offset correction
■
Defective pixel treatment
■
Low-pass filtering
■
Zoom generator
■
Graphic overlay
■
FireWire (IEEE 1394) interface
■
Embedded PC interface
■
Standard-format video-image generator (PAL/NTSC-FBAS, S-Video, RGB)
Summary of Contents for Jenoptik VarioCAM
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