InfraTec VarioCAM - Technical Description; Operating Principle; Functional Unit Descriptions

User Manual for the Thermographic System VarioCAM
®
high resolution
3. Technical Description
User Manual © InfraTec GmbH 2013 5
3 Technical Description
3.1 Operating Principle
The VarioCAM
®
hr is a thermographic system for the long wave infrared spectral range (LWIR) of (7.5 ...
14) µm. The lens images the object scene onto a microbolometer array at a resolution of (640 x 480),
(384 x 288) or (320 x 240) pixels. The electrical signal of the detector arrays is further processed by the
internal electronics. The electronics contains all the functions necessary for camera operation, such as
activation of the microbolometer array, A/D conversion, offset and gain correction, defective pixel
treatment, video and PC interfaces.
There is the choice of operating the system via the integrated membrane keypad at the top and rear of
the thermographic system or by using the joystick at the rear or via optional PC interfaces, available as
RS232* and FireWire (IEEE 1394)*. The use of these interfaces which are available depending on their
versions of equipment requires special software packages. You will find relevant details from Chapter 9
on, Hardware and Software Installation for VarioCAM
®
hr*, page 67.
3.2 Description of the Functional Units
Lens
The camera lens captures the IR radiation emitted by the object in the field of view and images it on the
detector array. Field of view (FOV) and resolution/size of the measuring point (IFOV, Instantaneous Field
of View) are determined at the same distance from the focal length f of the lens used.
The following standard lenses are available:
Thermographic system of resolution (320 x 240) pixels
lens focal length (mm) min. focus (m) IFOV (mrad) FOV (°)
wide-angle lens 12.5 0.2 2.8 (48 x 37)
standard lens 25 0.3 1.4 (25 x 19)
telephoto lens 1 50 2.0 0.7 (12.5 x 10)
telephoto lens 2 75 2.0 0.47 (8 x 6.7)
telephoto lens 3 130 5.0 0.27 (5 x 3.3)
close-up lens focal length (mm) focus (mm) field of view (mm²) resolution (μm)
close-up 0.17x for 25 149 (67 x 50) 209
close-up 0.5x for 25 50 (22 x 17) 70
microscopic lens 1.0x - 50 (11.2 x 8.4) 35