Archive for the ‘Night Vision Basics’ Category

Night vision devices work on a technology that enhances available light from environment many times to enable the user visualize in complete darkness or night. It allows vision at night. These devices are highly sensitive to light and the slightest amount of light is sufficient to make vision possible.

Photons that are available in light enter the cathode and as they pass through the tube get multiplied many folds and thereby eliminating huge amount of photons that makes visibility possible. Hence some amount of light is completely mandatory to visualize objects in complete darkness. Generation 1 night vision devices needed more light however with time technology has upgraded night vision devices to a level where vision is possible with bare minimum light source.

As an answer to the above direct question as direct answer would be NO! It is not effective to use a night vision device in complete darkness. But what seems to be complete darkness may not be a retarding factor in using night vision device. Generation 3 night vision devices are highly sensitive to light and are capable of detecting minimum available light. Light energy from natural sources such as moonlight, starlight or infrared light can be sufficient in enabling vision by use of a night vision device. Infrared light is invisible to human eyes and hence its presence can only be detected with a camera. So what seems to be complete darkness may also allow possibility of vision through a night vision device.

Technology has developed devices and solutions to enable vision in complete darkness in jungles, canyons and cloudy nights. Today many night vision devices today are coupled with infrared illuminator that makes it possible to see even in complete darkness. Infrared light is invisible to human eyes however camera lenses are capable of detecting infrared radiations in complete darkness.

Use of infrared or IR illuminators in dark is a very good solution for viewing objects in complete darkness. In closed environments it is usually completely dark and an illuminator can ease visibility with night vision devices. Illuminators provide enough light for clear and sharp objects and images and thereby clarity in vision. Many night vision goggles come with inbuilt infrared illuminators for closer focus and large distance viewing. When light is less the quality of picture or image produced is also of low quality. So an illuminator comes in handy in complete darkness and at places where light is less and a low quality night vision is used for viewing.

Infrared illuminators are devices that illuminate objects or areas that are scanty in light. Mostly used in photography to illuminate objects present in dark or poorly lit environments. This is the most typical use of an Infrared IR illuminator.

Infrared lights are electromagnetic radiations which has wavelengths larger than visible light and shorter than microwave radiations. In the absence of visible light infrared radiations enables visibility of objects. Infrared cameras use IR radiations to focus objects but when the focus is not strong enough an Infrared illuminator is to be used to provide enough infrared light for taking a picture.

One common use of infrared illuminator is CCTV or closed circuit televisions used for capturing pictures with better clarity even the dark. Infrared lights are not visible to human eye whereas cameras can detect and capture infrared radiations. This is where infrared illuminators come in handy for surveillance television; they detect infrared lights which human eyes cannot capture. Lighting infrared illuminators in dark areas is a good way of guarding a place with a CCTV. Since infrared lights or illuminators are not visible to human eyes they are used in bedrooms in the night without disturbing ones sleep.

Thus Infrared illuminators are a group of infrared LEDs brought together to illuminate a area with infrared light.

Infrared Illuminators emit infrared light which are widely used. Some of the important applications of Infrared illuminators are as below.

Night vision Equipments

All night vision equipments use infrared illuminators to make objects visible in the night. They are enhance visibility where light is very scanty.

Thermography

Infrared radiations from IR illuminators are used to roughly estimate temperature of an object. This method is called thermal imaging which is more popular in industrial and military applications. Commercially this technology is used in infrared cameras for cars.

Heating

Infrared illuminators are used for heating as infrared radiations form Infrared illuminator are source of heat energy. Infrared Sauna uses infrared radiations to heat occupants and also to remove frozen water from aircraft’s wings.

Today infrared radiations from illuminators are used for curing diseases and for physiotherapies as well. They are safely used in households for heating and cooking food. It is because they only heat objects without heating the surrounding environment.

Manufacturing industries too use infrared illuminators for annealing, print drying, curing coatings, melting plastics and many more. They have replaced conventional methods of heating in all industries.

Night Visions devices have undergone sea of changes since they were first developed way back in 1960’s. Gen 1, Gen 2, and Gen 3 are abbreviations of “Generation”. Gen 1, Gen 2, and Gen 3 refers to various stages innovation in the development of technology or product. Every generation produces a product with enhanced technology.

Here’s an overview of Gen 1, Gen 2, and Gen 3 night vision equipments.

Evaluation of night vision equipments are done on two major criteria. Light gain measures the degree to which available light (in dark) is amplified by night vision device. Resolution measures the sharpness and clarity of an amplified object.

GEN 1

The very first night vision device or equipment developed in 1960’s were very popular and in great demand among consumers. Consumers had great fun using these Gen1 night vision equipments. They were primarily developed for military use. This generation of night vision devices consisted mainly of simply configured tubes of image intensifiers. This imaging tube had photocathode, a phosphorous screen and were vacuum sealed. Light gain and resolutions were on lower side compared to next generation night vision devices.

GEN 2

After 20 years of invention of GEN 1 night vision equipments, GEN 2 was developed. GEN 2 was made up of different and better tubes. Micro-channel plates were the distinguishing features of this generation of NVD which enhanced the products. MCP or micro channel plate had a honeycomb like look where every cell had a multiple channels for letting the electrons entry. These MCP’s were located midway between photocathode and the phosphor screen which allowed up to 1000 electrons to hit the screen. Thus the MCP was able to enhance the light by almost 1000 times resulting in a brighter image with better resolution. Obviously they were more expensive than GEN 1 NVD and were put to use in professional surveillance and intentional uses.

GEN 3

While GEN 3 night vision equipments were more advanced, they continued use of MCP’s and introduced Gallium Arsenide photocathode or (GaAs) photocathode for improving the equipment’s sensitivity towards light. GaAs allowed more than 1000 photons that are more than what MCP did in GEN 2 night vision devices and hence was able to deliver brighter pictures on the photo screen. GEN3 NVD is latest innovation in NV technology and is the most expensive NVD of all. These equipments produce best images in least available lights. Thus they are best applicable in forests and canyons which are barely lit.