Lesson 4/Learning Event 2
Light intensification systems are expected to eventually replace the present active infrared systems
for tank-automotive applications. In the light intensification system, images formed by the ambient
light from starlight or moonlight are intensified by image converter-type tubes. The image
converter tubes have a high detective photocathode sensitivity in the visible and in the near-infrared
region. The light intensification system is characterized usually by its relatively small size and is
less complex than active systems because of the elimination of transmitting hardware. The major
disadvantage of this system is that, like normal viewing, range and performance depend on
atmospheric conditions.
Far-infrared systems operate by using light wavelengths that operate at the far end of the infrared
spectrum. Wavelengths in this region are transmitted fairly well by the atmosphere, except in
extreme humidity or rain. These systems use the natural radiation from a given object to provide
the power which detects the object. Systems of this type can be highly sensitive and can detect
even the shadow left by an object removed from its surroundings. These systems are receiving
much attention in target location systems. A disadvantage of this system is the large size of the
equipment compared to the light intensity systems.
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