The influence of radiation diffraction upon geometrical resolution of the thermograph with series structure of measuring line has been analysed in the paper. Analysis of thermograph properties in bands of 3 -5 J.LIT1 and 8 -1 0 ~m proved that when applying the aperture diaphragms the influence of the radiation diffraction upon geometrical resolution may by significant. This influence is stronger for larger values of the hole numbers in the applied diaphragms. It was shown that the thermal resolution of the thermography system can be improved by reducing the bandnwidth of the electronic system of the camera.

There have been presented the general approach of thermographic system designing problems. Metrological features an infrared thermography equpment have been formed considering various properties and parameters of objects, atmosphere, optics, detection system, electronic and display unit. There have been characterized the synthesis process of the IR thermographic system Algorithm of designing the thermographic system with sequence structure of measuring line with PC, PV or SPRITE IR detectors have been shown.