THERMAL IMAGING DEVICE BASICS

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Categories: Thermal Imaging

Thermal imaging is a method of improving visibility of objects in a dark environment by detecting the objects’ infrared radiation and creating an image based on that information. Thermal imaging works in environments without any ambient light and can penetrate obscurants such as smoke, fog, and haze. All objects emit infrared energy (heat) as a function of their temperature – the hotter an object is the more radiation it emits. A thermal imager can detect tiny differences in temperature, collect the infrared radiation from objects in the scene and create an electronic image based on information about the temperature differences.

Thermal images are normally greyscale in nature: black objects are cold, white objects are hot and the depth of grey indicates variations between the two. Our devices, however, have a variety of coloured polarity modes to help users identify objects at different temperatures. We offer thermal imaging hand-held monoculars for short, medium, and long-range observation, medium and long-range binoculars, goggles, weapon sights for a variety of weapons, and easy-to-use clip-on systems.

Thermal Imaging History

Before 1800’s, the existence of the infrared portion of the electromagnetic spectrum wasn’t even suspected.

Discovery of Infrared

In 1800, William Herschel, a German-British astronomer and composer, when studying the Sun’s surface and its spots for the Royal Society of London, conducted an experiment measuring the difference in temperature between the colours in the visible spectrum. He used plates of darkened glass of different colours (light filters) in his experiment and noticed that some of the plates were warmer than others. It made him think that temperature depends on a plate’s colour. He placed thermometers within each color of the visible spectrum. The results showed an increase in temperature from blue to red. When he noticed an even warmer temperature measurement just beyond the red end of the visible spectrum, Herschel had discovered infrared light! Herschel used terms ’radiant heat’ and ‘heat rays’. The term ‘Infrared’ appeared later in 19th century.

Research in 1800 1900 – developing IR detectors

1829 – Leopoldo Nobili, an Italian physicist, created the first known thermocouple, fabricating an improved thermometer, a crude thermopile.   

1833 – Macedonio Melloni, an Italian physicist, based on the Nobili’s instrument, created multielement thermopile that could detect a person 10 metres away.

1880 – Samuel Langley, an American astronomer and physicist, has perfected the design of bolometer, the invention of a Swedish mathematician called Adolf Ferdinand Svanberg from Uppsala University, who came up with the idea to place a thin darkened metal plate in infrared radiation and measure the change of its resistance.

Research in 1900s and now – developing thermographic camera

1913 – First industrial application of infrared technology to detect the presence of icebergs and steamships.

1929 – Kalman Tihanyi, a Hungarian physicist, invented the infrared-sensitive camera for anti-aircraft defence in Britain.

1930  1950

From 1930 to 1950 developments of thermal imagers were conducted in several European countries, which was stimulated by tense political situations and later war. During this time the first samples of single-element devices were produced – evaporographs, vidicons. With various effectiveness, they were used for detecting enemy forces. In 1942 the German army successfully applied evaporographs for communication in the battlefield.

1950 – 1960
In the 1950 and 60’s Texas Instruments, Hughes Aircraft, together with Honeywell developed single-element detectors, that could scan a scene and produce a linear image.

1970 – Philips and English Electronic Valve (EEV) develop the pyroelectric tube, which led to the first naval thermal imager used by the Royal Navy for shipboard firefighting.

1978 – The research and development department of Raytheon patented ferroelectric detectors based on barium strontium titanate (BST).

1980s – Microbolometer technology is developed.

1990s – Introduction of high resolution, uncooled focal plane arrays.

Now – Introduction of high resolution, uncooled Thermal Imagers at affordable prices.

To sum up, thermal imaging operates by capturing infrared radiation emitted by objects, enabling visibility in darkness and through obstructions like smoke or fog. Objects emit heat in the form of infrared energy, with temperature differences creating distinguishable images. While traditionally grayscale, modern thermal imaging devices offer diverse color polarity modes for temperature variation identification. Our range of thermal imaging devices includes handheld monoculars, binoculars, goggles, weapon sights, and clip-on systems. Trace the evolution from William Herschel’s 1800 infrared discovery to the recent advent of affordable, high-resolution, uncooled Thermal Imagers, revolutionizing applications across various industries.

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