Also, and you probably already know this, bonfires. Bonfires rock.
One of the side effects of the militarization of community policing is a growing dependence upon gadgetry. Such as, night vision goggles and infrared cameras. Bonfires create pockets of light which can effectively blind the night vision dependent.
Night vision amplification comes in two types - "image intensification" and "thermal imaging":
Night-vision equipment does not turn night into day.
1) Image intensification systems
Image intensification systems perform poorly in total darkness and more amplification causes visual distortions. By highlighting particular areas it can lead troops to concentrating on the light focus areas and not what is happening in unlit darker areas. Furthermore, they only work effectively over short distances and with slow moving objects. Image intensification rapidly diminishes at distances over 120 metres and the faster and more erratically an object moves, the less it can track it.
Because an image enhancing system works to increase lightness, a bright light shone on it in the near darkness will dazzle or blind its user. Even if the user is moving towards a bright light, and this includes a bright moon low on the horizon, he has great difficulty making out clear images and the equipment also casts long shadows which leads to accidents on uneven terrain. Therefore it can be made to malfunction by shining torches and, especially, by oncoming car headlights.
2) Thermal, infra-red imaging
Thermal imaging cannot be used to identify precise details on remote objects that are not distinguishable by different heat profiles. Depending on the quality of the night goggles, the maximum viewing range is from 30 to 120 metres in perfect conditions, and in adverse weather conditions much less. Weather conditions are the biggest threat to the efficiency of these systems. Dust, sand, smoke, fog, clouds and rain severely reduce their operational effectiveness.
Thermal night-vision equipment is also highly sensitive to red light. Even car instrument screens can disorientate the user and this is even more the case with red-lens flash lights.
A US army study also showed their limits used for night driving. It revealed that two thirds of vehicle accidents were due to night goggles. They proved very prone to terrain and roadway hazards like drop-offs and ditches greater than 1 metre and even with High Mobility Multi-purpose Wheeled Vehicles. This was particularly the case when they faced dusty or sandy conditions and when confronted with smoke or as a result of being dazzled by an external light source.
Finally, the experience of Kosovo and Iraq showed that it is very difficult to wear the special helmets for a long time. They are extremely uncomfortable and the strain on the eyes of viewing things through these goggles means troops can only wear them for short periods and not in longer conflicts. Therefore troops will not be able to wear them throughout the night in surveillance or battle.You can also pick up an assortment of LED flashlights, with blue and red beams, from as cheap as $2.
This public service announcement brought to you be the letter A.