4. Measuring the characteristics of infrared systems

Characteristic quantities of infrared systems can be measured directly on the electrical signal (video signal) by evaluating its amplitude, time constant and noise. This is an objective measurement, carried out using laboratory instruments (oscilloscopes, analysis computers, etc.), with the system subjected to known excitation (calibrated test patterns).

This type of assessment is more appropriate for infrared systems dedicated to measurement.

For systems designed for visual observation, characteristics must be measured on the final image rendered by the display unit, usually a monochrome or color cathode-ray tube.

In this case, the results depend on how the image contrast and brightness are adjusted. Two operating modes can be defined for these measurements (figure