The IR-camera is designed as an optico-mechanical scanner with the single-element liquid nitrogen-cooled InSb sensor (receiver). The optical system consists from line and frame scanning mirrors mounted in front of a lens objective which concentrates radiation on the IR-receiver. The motions of the frame and line scanning mirrors are mutually synchronized to ensure a high repeatability of the geometry of the successive frames. The image is focused by means of a movable lens. The small number of reflecting and refracting surfaces in the optical system make the camera highly sensitive and simplify its alignment. Absolute temperature calibration and drift cancellation are performed during the flyback of the frame.

  The IR-camera scans the examinated object and forms a video signal level, which is proportional to the energetic brightness of the appropiate point in the wave length range of 3-5m. The interface board (together with the software package) converts the video signal into an image frames sequence (reading a static thermogram or an IR film). Brightness of each point of this image corresponds to a specific temperature (which changes from frame to frame). The temperature and tones of the used palette are in controlled accordance each other.

The software package makes possible to display the thermogram on the screen (with the level and range being adjustable within wide limits - during the recording), to record it on a floppy or hard disk of the computer. Means are provided to build projections and thermal profiles of any section, to adjust the image contrast, to carry out filtering, to select any of the available palettes. Additional text information can be written on the frame and written information  can be obtained in the form of a computer printout.
 

The system has the following features:
 
 

detector :	liquid nitrogen cooling (InSb)
spectral response:	3 - 5m
spatial resolution:	2mrad
frame scanning time:	1.5s
temperature sensitivity per frame at 30°C:	0.05°C
temperature measuring range:	-10°C to 200°C
temperature operating range:	-10°C to 40°C
field of view:	20° x 20°
frame resolution:	256 x 248 pixels
power consumption:	2.5 W; 6 Vdc
dimension:	100 x 140 x 210 (mm)
mass:	2.5 kg

  The data acquisition is performed in two steps:

• thermal data recording on a LAPTOP computer.
  
• thermoimages interpretation with the dedicated program.