Evolving night vision

The one instrument that revolutionized warfare is the night vision device. Offensive and defensive operations no longer depended on natural light which meant that warfare became a 24X7 business giving rise to the concept of “surgical strikes”, a phrase that has caught the imagination of the Indian public.

That, in spite of the ability to see the target quite clearly and to pick it out from among a clutter of other objects, modern warfare as seen in the Iraq-Syria- Libya-Yemen salient and before that in the former Yugoslavia in Europe is as destructive of human life and property is because the destructive mindset prevails over the humanitarian as is evident from the mass of refugees that are flooding Europe.

Be that as it may, the night vision device is still in the process of evolution. Its growth is marked by ‘generations’ that are indicative of the inherent qualities at a given stage of its employment on the battlefield. However, the designation of ‘generation’ which was largely a benchmark for export control (night vision is a closely guarded technology) has since been replaced by a category known as the ‘figure of merit’  wherein the merit can be quantifiable in the form of the “number of line pairs per millimetre multiplied by the tubes signal-to-noise ratio”. The higher the figure the better the image intensification.

Image intensification

At the early stages of development the night vision devices were essentially image intensifier tubes which were both bulky and heavy and the intensification of the desired images in the dark was somewhat fuzzy. The ‘generation’ categorization depended on the amplification provided by the device. The early devices provided an amplification of 1000 under moonlight conditions which was not always available. Later improvements led to the ability to acquire and discern images of human or motorized vehicles like tanks and soft skinned vehicles destruction of which could lead to strike capability denudation for the enemy. Improvement  of the system could be gauged by the fact that there was no longer any need for moonlight to do the job, starlight would do.

Yet the requirement of all-weather, all-terrain and the “fog of war” situations where dust, smoke, mist, rainfall could each contribute to the general deterioration of the image intensification. This demanded refinements.

The initial infrared floodlight that illuminated segments of the battlefield, where enemy presence was suspected, was penetrated by what was then called “black light”. It showed up the difference between the heat emission of the background and the object-man or machines-in the foreground and made it possible to aim and fire with a great deal of certainty of a hit. That the earlier generation of infrared device was a 30 cm (nearly one foot wide) searchlight will indicate the kind of bulk and weight that was involved.

The introduction of a micro channel plate in conjunction with a photocathode made for a brighter image. That became the ‘second generation’. The amplification of image grew to 20,000 times but bulk was still a problem.

The ‘third generation’ was sparked by the creation in the laboratory of gallium arsenide crystals which could be sliced into wafers for use in the photocathode. This helped improve  the image intensification by as much as 30,000-50,000 times.

The transition to a next higher level came with the introduction of the automatic gated power supply system that controlled the photocathode voltage by a swift series of switches on and off. This helped obviate the flare and disturbance in focus on the image caused by bomb-blasts on the battlefield. It sort of evened out the transmission so that the intensity remained near constant even as light conditions changed on the battlefield. Simultaneous with this came the reduction in the thickness of the ion barrier that allows the night vision device to operate at a higher luminous sensitivity of up to a level of 2800 Kelvin.


Stages in the evolution of the night vision devices include monocular eyepieces strapped onto helmets and the transition to binoculars that were both soothing to the eyes as well as afforded a more rounded image because of the stereo vision which removed the parallex that the single lens could not. Combined with autogating it helped the viewer to keep the target in view irrespective of the light conditions on the battlefield. It has special significance for pilots during the take off stage in particular when apart from runway lights he has to lift his plane out of a welter of city lights in homes and highways even as the sky above is dark.

Globally, among other improvements in night vision devices is the introduction of the panoramic view by increasing the angle from the 45 degrees to a little above 90 degrees. It is a definite advantage given that the whole emphasis in military surveillance has been to be able to train a warrior to take in as much of the periphery without having to shift his eyes from the center line. Peripheral vision contributes immensely to awareness and especially more so when battlefield awareness is the current buzzword.

The paucity of night vision devices has long been a bugbear in India. For long the demand has been for “third generation” devices. Since India has for several decades been able to produce Gallium Arcenide crystals at its Solid State laboratory in New Delhi, it should by all expectations, have been able to transit smoothly from the “2nd generation” to the “third generation”. Apparently the trouble lay in acquisition of technology for autogating.

Bharat Electronics Ltd has been working with several other Indian laboratories to bridge the gap. In the meantime it received an order of about 30,000 second generation night vision devices based on the image intensifier tube technology. Much of the leaked reports of the “night blindness’ of the Indian Army arose from the delays in executing the order.

India requires the whole range of night vision devices not just for the tanks (which tend to grab the headlines) but also for the modernization and upgradation of the Indian infantryman. It is at this level the need to be able to see and shoot the cross border terrorists, who almost daily are attempting to infiltrate into India to cause mayhem in Jammu and Kashmir, is imperative. Under the now defunct Future Indian Soldier As System  (F-INSAS) it was enunciated that he would have at hand the facility to see and shoot in the dark without any hesitation.

India and the US are currently in a state of strategic partnership. India should make out a case for import of the full requirement of the Indian infantryman of not the so-called “third generation” of night vision devices but the latest in the “Figure of Merit” description that was initiated in 2001. Under this policy the benchmark of  US-made tubes with a FOM greater than 1,400 are not exportable outside the US. Nonetheless there is a proviso that  the Defense Technology Security Administration (DTSA) can waive that policy on a case-by-case basis. India should make it clear to the US that if “strategic partnership” is to have any meaning India must be given the means to be able to tackle effectively the cross border terrorism that it is being subjected to.

There should be a joint venture by which India should produce night vision devices that can be attached to the infantryman’s rifle and carbine on a priority basis and the technology can be applied to requirements for the armour and Indian Air Force requirements as well.