A camera is an optical instrument used to record images. At their most basic, cameras are sealed boxes with a small hole that let light in to capture an image on a light-sensitive surface. The light from the source moves in a straight line. When that beams of light hits an object, the light bounces off that item and into your eyes, allowing you to see whatever is inside the room. A camera lens collects and focuses the light. Film is made up of light sensitive materials. When those materials are hit with light from the lens, they captured the shape of the objects and details like how much light is coming off of them. In the dark room, the film that was exposed to the light is again put in a series of chemical baths to eventually create the image.
Infrared radiation extends from the nominal red edge of the visible spectrum at 700 nanometre (nm) to 1 millimetre (mm). This range of wavelengths corresponds to a frequency range of approximately 430 THz down to 300 GHz. Below infrared is the microwave portion of the electromagnetic spectrum.
Visible region of the spectrum has wavelengths from about 400-700 nm.
Thermal Imaging Camera
The thermal imaging camera is a type of thermo graphic camera that helps in measuring the temperature differences of surface. This helps in identifying any potential fire hazards. The areas with different temperatures are pictorially represented.
Thermo graphic cameras form the image with the help of infrared rays. They work similar to the normal camera but use infrared instead of normal light rays.
Detectors in the infrared camera convert the incoming infrared energy from the infrared spectrum to the visual spectrum so we can see the infrared energy. Infrared Thermography- Infrared thermography is the technique for producing a visible image of invisible (to our eye) infrared energy emitted by objects.
How does Infrared Thermal Imaging Camera Works???
- Infrared light is emitted from the body.
- Emitted light is converged by the convex lens.
- Converged light is then send to the sensors, which detects the light and sense the temperature.
- Then it is sent to the image processor, which process the temperature and shows the image.
- Then we have the display screen on which we can see the image.
Types of IR Camera
There are mainly four category of IR Camera, and those are following
- Hyper Spectral camera- It has high spectral resolution.
- High Speed – Up to 90,000 frames per second.
- Multispectral- Time Resolved Multi Channel Imaging
- High Dynamic Range – Continuous Acquisition up to 2500°C.
Applications
Infrared thermal Imaging camera has a very wide range of applications in Research and Development Labs, Fuel and Mining Industries, Defence and Security services, in various types of Non Destructive Testing’s and many more. Here we have tried to list out applications of Thermal Imaging Camera in every field.
Accurate in-band thermal radiance measurements for target detection, identification and recognition
Efficient characterization of military target infrared (IR) signature plays an important role in any countermeasure defence program for the design of unmanned monitoring systems capable of ranging and tracking different targets as well as performing automatic detection and recognition of potential threats. In order to do so, large IR signature databases are built upon testing of multiple targets such as camouflage materials under various backgrounds conditions, at multiple wavelengths, and using different sensor technologies.
Combustion Analysis
Most combustion reactions generate infrared-active gases such as carbon dioxides (CO2) and water vapour as well as known pollutants like carbon monoxide (CO) and nitrogen oxides (NOx). On this regard, infrared imaging represents an interesting diagnostic tool as it allows chemical imaging and temperature measurement at the same time. High-speed infrared imaging is useful for characterizing fuel injection, ignition and combustion in internal combustion engines (ICE), gas turbines or jet engines, regarding which lowering fuel consumption and soot generation represents an important research aspect.
Experimental Mechanics
Characterization of mechanical properties such as Young’s modulus, shear strain, viscosity and fracture toughness is very important in the development process of new alloys and composite materials. Researchers typically carry out many different measurements like tensile displacement tests, compression tests and fatigue tests using extensometer and split-Hopkinson bars setups. Infrared imaging allows characterizing the energy released by the investigated material as it undergoes elastic and plastic deformation up to the fracture point.
Plasma Physics
Nuclear fusion represents one of the best alternatives for generating electricity in order to meet the future needs for power. Research on high-temperature and high-density plasma is carried out in tokamaks, stellarators, and helical devices. Since plasma can reach temperatures of the order of tens of thousands of degrees, it needs to be contained in a strong magnetic field. High-speed infrared imaging can help to characterize the integrity of the material forming – for example – the diverter and the armour wall during the experiments.
Non Destructive Testing
The presence of cracks and defects changes the thermal properties of the materials. Infrared imaging provides unique insights for remote inspection of various objects such as electronic components and artworks where non-contact analysis is more suitable. The correct interpretation of thermal flows can reveal the presence of structural changes within the material and prevent failures.
Airborne mapping and Surveillance
High spatial and spectral resolution hyper maps can be readily being obtained for geological surveys, pollution monitoring, and surveillance applications.
Gas Detection
Infrared imaging can help visualize fugitive emissions and small gas leaks under various environmental conditions and industrial contexts. As many gases are toxic and/or flammable, like natural gas (CH4), efficient gas detection from a remote location is advantageous for safety purposes. The selectivity brought by high-resolution infrared hyper spectral imaging allows identifying the chemical nature of the gases, reducing at the same time the frequency of false alarms.
Mineral Identification
Many minerals display spectral features in the thermal infrared spectral range. Remote hyper spectral imaging allows the mapping of large areas. Here, a geological survey was carried out in an asbestos open-pit mine. We were able to detect the spectral signature of serpentine from a distance of over a hundred of kilometres.
Ballistics
High-speed infrared cameras can be very useful for ballistic studies, as they allow performing terminal ballistic, aeroballistics, and muzzling flash analyses. Projectiles in trajectory, flight behaviour, aerodynamics, impact and launching can all be observed.
Volcanology
The unpredictable behaviour of volcanoes makes infrared remote sensing a very attractive investigation tool for surveillance and academic purposes. Passive infrared hyper spectral imaging allows the detection and identification of multiple gases like sulphur dioxide (SO2) and silicon fluoride (SiF4) coming out from craters and fumaroles, from distant locations, without the need of additional equipment.