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About Our Thermal Products


   :: How Thermal Imaging Works ::

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Imaging Technology

Forward looking infrared technology, sometimes referred to as a thermal imager or infrared camera is a device that creates an image using infrared energy, similar to a conventional video camera that creates an image using visible light. Instead of using the 0.4 – 0.7 micron range of a visible light camera, infrared cameras operate in longer wavelengths that range from 3 - 5 micron to 8 - 12 micron.

Visible Light, Infared, Ultraviolet, How Thermal Works FLIR technology can be a useful tool that allows you to see in complete darkness and through most weather conditions including rain, smoke, haze, and dense fog. Here we will explain the process of converting infrared energy into an image and displaying it on a monitor.
To create an image, the infrared camera uses a germanium lens to collect all of the infrared energy in a scene and focus it on to an infrared detector.

The information is then sent to the image processing electronics which converts the data into a clean crisp image that can be displayed on a video monitor.

Uncooled IR Detectors

Uncooled thermal imaging dates back to the mid-1960's with the pyroelectric vidicon. This product was used in the production of fire-fighting cameras. Between that time and the mid-1990's, most thermal imaging has been of the cooled variety, meaning that the sensor elements are cooled to -200 C, or -321 F. During this time research into uncooled thermal imaging was pursued in order to reduce cost, weight, and increase reliability. In the mid-1990's cooled arrays were very common, and uncooled arrays were coming out of the research labs and moving into production cameras. The main types of arrays today are known as microbolometer using vanadium oxide, microbolometer using amorphous silicon, and BST (barium strontium titanate). These three types have made the most significant market change of any uncooled technologies.


The detector works by measuring the temperature of each of its pixels. The material is designed to change its electrical resistivity as the

Thermal, How thermal works, pixels temperature changes. The temperature of the scene is focused on the material by the lens system. The detector has a quite small mass, and is thermally isolated from its supports so that its temperature changes rapidly with the small amount of focused energy. The material varies in its reaction to temperature across the array, so precise calibration needs to be done by the processing electronics in order to generate a clear picture. So that the calibration data can be measured, it is common to have a shutter that can close off the optics. This calibration is done while the camera is operating every couple of minutes (between 5 and 60, depending on the design). The calibration is objectionable because the image is frozen for approximately 1-2 seconds, while it is being accomplished.

Microbolometers are generally temperature stabilized by means of a thermo-electric (TE) device. The TE device heats or cools the detector in response to a particular voltage. Within the past 3 years, research has been successful in better understanding the detectors response to temperature. As a result, it is becoming more common that these detectors no longer need temperature stabilization, and are being delivered to customers without TE devices.

These detectors are used in a variety of roles. There are several manufacturers, and they are spread across the United States and Europe. There are also several suppliers who sell the detector as a component, ready to be coupled with processing electronics, and then designed into a full camera system. They are generally a little more expensive then BST, however the image quality is often better depending on how the system is designed.


The largest application for Amorphous Silicon (ASi) has been fire-fighting. Historically, they are lower resolution and lower frame rate (20 Hz) until recently when upgrades have been developed. ASi has been positioned as a lower cost alternative to Vanadium Oxide because it can be made with foundry machinery common for the manufacture of other electrical components, without many of the specialized processes of other detector technologies.

To use the detector, the system designer must focus the infrared energy on the detector, which heats the detector elements, just like vanadium oxide detectors. When the elements change temperature, they also change resistivity. The processing electronics collect data about the resistance change to generate the picture of the scene. A shutter is often employed every couple of minutes, which freezes the image for 1-2 seconds, to collect calibration data.

ASi detectors also employ a TE device to stabilize their temperature. Similar to vanadium oxide, designers have developed algorithms to use the detector without a TE device, allowing a further reduction in cost. Typically, ASi detectors have a slight disadvantage to Vanadium Oxide in image quality, while a slight advantage in cost.


The detector outputs infrared data by looking at the change in temperature over time. Therefore, if the detector were held fixed, looking at a stable scene, it would eventually (over a couple of seconds) show nothing at all, just one shade of gray. To correct this problem, designers added a shutter wheel in front of the detector that spins continuously at a known rate. The wheel alternates between semi-transparent and transparent, which the readout electronics compare to determine the scene. A by-product of this moving disc is that there are fuzzy edges around everything in the scene. The fuzzy edge affects the image quality and the range performance of the system.

BST is an uncooled technology meaning that it does not require cryogenic cooling. It does however require temperature stabilization. Typically, the detector is warmed slightly and then a regulator keeps the temperature constant.

IR Spectral Bands and Performance

The word "infrared" refers to a broad portion of the electromagnetic spectrum: everything between visible light and microwaves. Much of the infrared range is not useful for ground- or sea-based imaging because it is blocked by the atmosphere. The remaining portions of spectrum are often called "atmospheric transmission windows," and define the infrared bands that are usable on Earth: Near Infrared (NIR), Short-Wave Infrared (SWIR), Medium-Wave Infrared (MWIR), and Long-Wave Infrared (LWIR).

Thermal, How Thermal works

Atmospheric transmission of infrared bands
(Courtesy Raytheon)

Thermal Body Heat, How Thermal works, how thermal vision works

Since NIR and SWIR are so near the visible bands, their behavior is similar to more familiar visible light. Energy in these bands must be reflected from the scene in order to produce good imagery, which means there must be some external illumination. Both NIR and SWIR systems can take advantage of sunlight, moonlight, starlight, and an atmospheric phenomenon called "nightglow," but typically requires some type of artificial illumination at night. Arrays of infrared Light Emitting Diodes (LEDs) often provide a very cost effective solution for short-range illumination, but achieving good performance at distances of over tens of meters requires more directed illumination. Typical medium to long-range systems employ a focused beam from a laser or specialized spotlight, though special consideration of eye-safety issues is required.
While NIR and SWIR imaging systems often employ sensors that are more exotic than those found in consumer-grade camcorders and digital cameras, glass is transparent to wavelengths as long 3μm, so normal lens systems can be used and windows can be seen through. Because NIR has a wavelength longer than visible light, and SWIR a wavelength that is longer still, energy in these bands is scattered less by particles suspended in the atmosphere. This means that SWIR, and to a lesser extent NIR, systems are tolerant of low levels of obscurants like fog and smoke.

The MWIR and LWIR bands are often called "thermal" bands because a typical scene emits radiation in these ranges. An imaging system that operates in these ranges can be completely passive, requiring no external illumination because it is able to sense the energy that is radiated directly from objects in the scene. Two major factors determine how bright an object appears to a thermal imager: the object's temperature and its emissivity. As an object gets hotter, it radiates more energy and appear brighter to a thermal imaging system. Emissivity is a physical property of materials that describes how efficiently it radiates. Because cloth has a lower emissivity than skin, to a thermal imager cloth will appear darker than skin even when both are exactly the same temperature.

Thermal vision in smoke to see body heat

Atmospheric At these long wavelengths, infrared radiation behaves differently from visible light. Glass is opaque in the LWIR band, and blocks most energy in the MWIR band. Consequently, LWIR and MWIR systems cannot use inexpensive glass lenses, but are forced to use more exotic materials like silicon or germanium. Glass windows are also not transparent in these bands, so they appear brighter or darker according to their temperature. Since radiation in the MWIR and LWIR bands is not transmitted by water, rain can coat a scene and wash out much of its thermal contrast resulting in a duller image.obscurants cause much less scattering in the MWIR and LWIR bands than even the SWIR band, so cameras sensitive to these longer wavelengths are highly tolerant of smoke, dust and fog. Even small effects like atmospheric turbulence can add up over very long distances to impact range performance, allowing LWIR an edge over MWIR.

Hotter objects emit more of their energy at shorter wavelengths. The peak emissions of an object at room temperature falls in the LWIR band, so for objects at normal earthly temperatures, a MWIR system must be more sensitive than a LWIR system to achieve identical imaging performance. The emissive peak of hot engines and exhaust gasses occurs in the MWIR band so these cameras are especially sensitive to vehicles and aircraft, but since hotter objects emit more total radiation, they are still easily detected by LWIR imagers.

   :: FLIR LS-Series Thermal Imaging Camera Features ::

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Hardened for law enforcement and surveillance, the FLIR LS-Series Thermal Night Vision Monocular is designed for everyday use. Rather than rush on the scene with a flashlight that instantly gives away your position and only illuminates your immediate area, FLIR LS thermal imaging camera is just as portable, handy and exponentially more effective. At only 12 ounces and 7-inches long, FLIR LS is destined become an essential tactical advantage.

All of FLIR’s considerable experience in law enforcement and military applications culminates in the FLIR LS thermal imaging camera, including:

  • On stakeout or in pursuit, detect suspects at 1,000 yards or more
  • At 12 ounces and 7 inches, LS is easier to handle than your baton
  • Select zoom, palette and laser features with one finger

Learn more about LS-Series thermal imaging features in the videos below.

   :: FLIR HS-307 and HS-324 Compact Tactical Fusion Camera Features ::

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FLIR’s H-Series handheld thermal imaging cameras let law enforcement officers see clearly in total darkness, providing an undeniable tactical advantage.

Using the same technology as airborne law enforcement units, H-Series gives officers the information they need to make quick decisions, enhancing mission effectiveness, maximizing operational capabilities, and improving officer safety. 

People can’t hide their heat, so H-Series lets officers:

  • See suspects in total darkness
  • See through smoke, dust, and light fog
  • See through camouflage and foliage in any lighting conditions
  • See more – and see farther – than with other low-light night vision goggles and cameras.

Using a 320 × 240 thermal imaging core, H-Series provides four times the image clarity and detail of earlier systems, allowing officers to see more of their surroundings than any other night vision technology in the world. FLIR’s advanced image-processing algorithms produce, crisp, clear thermal video day and night, in good weather and bad.

Best of all, H-Series is the first personal thermal imaging camera affordable enough to give every officer on the job the unsurpassed tactical advantages of full-resolution thermal imaging night vision.

   :: FLIR BHS-X and BHS-XR Bi-Ocular Tactical Fusion Camera Features ::

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The new FLIR H-Series Bi-Ocular camera gives law enforcement officers the ability to see more and see farther in infrared than with other low-light night vision goggles. Featuring a full coverage eyepiece, inter-ocular adjustment, ergonomic comfort, straightforward controls, and the rivaled performance that only FLIR can deliver, the FLIR H-Series Bi-Ocular is a must-have for extended patrols, covert surveillance, critical infrastructure protection, and high-threat security missions.

FLIR H-Series Bi-Ocular Features

Unlike traditional night vision, thermal imaging technology detects radiation and temperature differences. That means you can see even in pitch black, as well as through smoke, light fog and foliage. Your FLIR H-Series Bi-Ocular includes:

    • Quick-Disconnect Modularity: Choose one or all of the following lenses: 35 mm, 65 mm, and 100 mm. Raised rubber sleeves and captive low-profile lens caps protect your lens investment.
    • Extended Range Options: Standard 320 x 240 with 2x digital e-zoom is powerful enough for you to detect a human about 2 kilometers away. Optional 640 x 480 resolution comes with up to 4x digital e-zoom that is powerful enough to detect a human almost 2.5 kilometers away.
    • Fast Power & Battery Swap: Latched door offers quick access to batteries. “Snap” FLIR Scout BHS Bi-Ocular onto its quick-release hot shoe to switch instantly to AC power.
    • Standard Photo & Video Capture: One-touch recording, focus, and zoom is a necessity in the field when your target is on the move.

   :: FLIR FC-Series Thermal Camera Features ::

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The new FC-Series of thermal cameras from FLIR sets a new performance standard with Wide Dynamic Range Thermal Video for superior image quality when other thermal cameras fail.

Designed for high performance, easy installation, and long-term reliability, FC-Series cameras with WDR Thermal Video give you the best image quality and optimized video streams so you’ll get the most accurate results from your analytics– even in challenging imaging environments like when the camera is facing the rising or setting sun.

FLIR FC-Series Security Camera Features

  • WDR Thermal Video for industry-leading image quality in all conditions
  • High-performance, all-weather, industrial-rated system
  • 12 VDC, 24 VAC, and two POE power input options
  • Simultaneous IP and analog video outputs along with IP and serial control interfaces for easy integration into IP networks or analog video environments; use them in an existing analog environment, and migrate easily to a future IP network
  • Open IP standards for plug-and-play integration; ONVIF compliant
  • Streaming digital video available in H.264, MPEG-4, or M-JPEG formats
  • Advanced thermal image processing with Digital Detail Enhancement (DDE) for high-contrast images in dynamic thermal scenes

   :: FLIR ThermoSight® R-Series Weapon Sight::

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The ThermoSight R-Series is the ideal night vision, non-game hunting scope because it detects heat energy, instead of visible light. Day or night, the body heat of animals will stand out against cooler backgrounds when seen through the R-Series scope.

Conventional image intensified (I2) night vision scopes can’t match the power of thermal because they require illumination from moonlight or other sources. They also can’t reveal what’s hiding in the shadows or in low-contrast environments in the same way thermal can.

The R-Series offers up to six different detection palettes, including FLIR’s exclusive InstAlertTM, which displays the hottest temperatures in red so you can detect animals, people and other warm objects more easily.

The ThermoSight R-Series is built to perform under extreme conditions. An internal shock reduction system (SRS-MTM) is qualified for a MSR semi-automatic platform, up to .30 Cal. Plus, the R-Series’ water-resistant casing can be submerged in up to three feet of water. FLIR is so confident in the reliability of the R-Series we offer a three-year warranty (with registration) on the scope, and a 10-year warranty on the internal sensor.

FLIR ThermoSight R-Series Weapon Sights include

  • Multiple resolution and lens options
  • 3-inch eye relief
  • Up to 16x magnification
  • Advanced Image Correction
  • Shock Reduction System
  • Simple, 4-button operations
  • Three reticle settings with a repeatable and dependable zero

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