Purchasing a Thermal Imaging Camera


Wanting to buy an infrared thermal imaging camera but not sure where to start or what to look for when purchasing? Many factors should be weighed when you buy an infrared thermal imaging camera. This guide goes over some of the basic factors to be considered as well as tips to buy the correct thermal camera for your application.


Download: Thermal Imaging Camera Buyers Guide


If you have any questions please feel free to call us Toll Free at 1-866-861-0788 to discuss your application and how our infrared cameras can work for you.

General Information


Typically you will hear both infrared and thermal imaging; they are really the same thing. Infrared Instruments DO NOT Measure Temperature; they measure Infrared Radiated Energy only. Thermography is the discipline concerned with the acquisition, storage and analysis of radiated energy using a thermal infrared imaging system. Thermography directly refers to the active collection and interpretation of infrared data, and is the measurement of temperature remotely to indicate equipment health and assigning a color based on the temperature.



Qualitative or Quantitative?


Basically Qualitative means that you will not get a temperature reading, but will be able to view thermal differences, while a quantitative thermal camera will give you accurate temperature readings. Most thermal imaging cameras are qualitative; meaning that they have the built in software to produce an accurate temperature reading.


Determine the Type of Infrared Camera that best suits your application; qualitative or quantitative?


  • Qualitative Measurement - the process of obtaining and interpreting thermal images based on thermal contrast in order to identify anomalies; the purpose is more to determine where a temperature difference exists than what the temperature difference is between the target and its surroundings.

  • Quantitative Measurement - the process of obtaining thermal images with correct temperature readings. Especially useful in situations when the exact temperature or temperature difference of the target determines whether it falls in or out of a determined criteria or range of acceptability. Also important to R & D and process control situations.

Example of Qualitative Measurement

Example of Quantitative Measurement

Several times a week we get calls in the office asking about security cameras; they do not necessarily need temperature measurement or radiometric cameras and are usually just as well off with night vision or infrared illuminator CCD Security Cameras. We do not sell CCD Security Cameras and would not suggest someone buy a radiometric infrared camera if it is not needed for their application.

Portable, Fix Mounted, or Pan & Tilt Thermal Imaging Unit?


At ICI we offer a variety of infrared cameras and enclosures ranging from airborne vehicle mounted, fix mounted, vehicle mounted with stabilization, pan and tilt, and handheld thermal imagers.

  • Portable Handheld Thermal Imaging Unit - ToughCam
  • Portable Handheld thermal imager - ToughCam EL image


Portable Handheld Thermal Imager

The most popular thermal imaging cameras are our handheld units, which are useful for a number of applications including research, electrical, mechanical, medical, veterinarian, fire fighting, process control, building inspections, and energy audits. Their ease of use, portability, and light weight make them ideal for many jobs and applications.

There are hundreds of different types of handheld thermal imaging cameras, each with a unique set of functions and features. When purchasing a handheld camera the buyer should be aware of the following:

Portable Handheld Thermal Imaging Unit - T-Cam 160


  • Weight and design can be a be factor if the camera will be used for any extended period of time.
  • Battery Charge time, accessories, etc. should be considered depending on the job at hand.
  • Other considerations:
  •         Voice Annotation
  •         Size of LCD - ability to rotate or move screen for difficult angles
  •         Lens size
  •         Image storage capacity
  •         Video output
  •         Resolution
  •         Image Refresh rate

Fix Mounted and Pan & Tilt

At Infrared Cameras Inc, we will custom design and manufacture to your specifications. Depending upon your particular application, there are several designs and models from which to choose.

When buying a fix mounted or pan and tilt thermal imaging camera, many factors should be considered:


  • Does the camera need to have any special environmental protections, e.g. will it be exposed to extreme heat/cold or will it be exposed to humidity?

  • Does the camera need to be fix mounted or should it be able to pan and tilt? Vehicle mounted thermal imaging cameras require specially outfitted enclosures. Mounting to vehicles, aircraft, and boats will also require stabilization as well as conversion to run off the vehicle's power.

    If your application requires a portable fix mounted unit, there are several fix mounted units that are small enough to be easily packed and moved from location to location.Thermal Imaging Cameras can be mounted on practically any vehicle, including robots, satellites, etc.

  • Does the system need to be autonomous?

  • If a thermal imaging camera is to be in one position, all weather and environmental factors should be weighed into the purchase of a thermal imaging camera. For certain environmental conditions, heating and/or cooling for the camera may be required as well as humidity defense.

  • How the thermal camera will be hooked up to power and monitoring stations should be considered as we can modify our thermal cameras to run on an alternative power sources, e.g. solar panels. WiFi can then allow thermal cameras to be placed in remote locations.

ICI Flare Monitoring Fix Mounted Thermal Imaging Camera

X32 Dual Pan & Tilt Thermal Imaging Camera System

Thermal Imaging Software

Ensure software has the functions necessary for your application.


Several unscrupulous companies may try to sell you a “watered down” version or a lite version of their software to allow viewing only of the images or limited functionality. At ICI we offer several software packages, but all of them are the full software suite with all functions enabled. Additionally, Infrared Cameras Inc. offers no restrictions to multiple users across multiple computers; there a NO CHARGE for multiple licensed users for the software.

IR Flash Professional Thermal Imaging Analysis Software

Ensure the Thermal Imaging Camera has the built in features necessary for your application.


Our infrared cameras offer single and multiple temperature measure points and should have accuracy at the industry standard of ± 2°C or ±2%; this is the industry standard and anything above that may provide unreliable or inaccurate temperature measurements. When purchasing your infrared thermal imager, you need to be aware of the following:


  • Make sure your camera allows you to adjust the emissivity settings. If you cannot adjust emissivity you cannot get accurate readings.

  • Buy a camera with video output in the envent that you need to view or record live video. Also, ensure the camera is HD 50/60Hz with a high resolution for the best possible viewing.

  • Buy a thermal imaging camera that outputs to industry standard format image, i.e. as a JPEG or Tiff, that can easily be e-mailed to clients.

  • Ensure your camera will be able to measure temperature high or low enough for your application.

  • Buy a thermal imaging camera with trade-in potential, i.e. you should buy from a manufacturer that offers loaners, trade-ins, rentals, and demos.

  • Make sure the manufacturer has an experienced sales staff trained in thermography.

  • Determine if the camera includes temperature tracking, visible camera, laser pointer, alarming features, correct focal length, and the correct angle of lens

  • Look into all lens options to find the one that best suits your application, and see if there are optional lenses available for an upgrade.

  • Discover all of the available accessories, i.e. case, battery, charger, etc., for the best deal.

  • Buy a camera with no proprietary accessories or batteries. Having the option to pick up a back-up battery at your local Radio Shack can save you a lot of money and time.

Other Considerations and Tips


  • Warranty - Ensure that the camera comes with at least a standard 1-year warranty. Many manufacturers offer a 2-year warranty or the ability to purchase an extended warranty. If your thermal camera is critical to your business's success, make sure that you can be provided with a loaner camera in case your thermal camera needs repairs.

  • Thermography Training - To ensure accuracy, all personnel using the thermal imaging camera should be properly trained in Level 1 Thermography. Training can help one better determine the type of camera needed for the desired application.

    Consider renting or getting a demo unit during your training class before actually purchasing the thermal camera. Instructors will review individual cameras as well as software for the benefit of their students.

  • Demos - At ICI we offer a "Try before you Buy" rental program. You rent the camera as usual; however, if you decide to purchase the unit, we will waive the rental fee up to one week.

  • Medical Applications - When purchasing a thermal imaging camera for medical purposes, ensure that the camera has been cleared by the FDA for use as a medical device; this guarantees that the camera is of the highest quality and accuracy for medical use. Infrared Cameras Inc. has recieved FDA 510k Clearance to market our S and P series thermal imaging cameras as medical devices.

  • Thermal Sensitivity or NETD - Thermal sensitivity is measured in terms of milliKelvins (mK). The lower the sensitivity the more sensitive the camera. A low sensitivity indicates the camera's overall image quality and,thus, can affect accuracy when calculating temperatures.

  • Calibration and Repair - Another good point to consider is whether the manufacturer you are purchasing from has their own Calibration and Repair center. The majority of thermal cameras require calibration every year or two depending on use. If the camera has to be sent overseas for repair or calibration, you may be without a camera for several weeks or even months. Therefore it is important to find out if a loaner camera will be sent while your camera is away for calibration or repair.



This buyer's guide was written by Infrared Cameras Inc. for general informational purposes. Most manufacturers will meet or exceed these suggested buying requirements. Feel free to contact us for more information or questions regarding your purchase of a new thermal infrared imaging camera.

Exportable and Embargoed Countries for Thermal Infrared Imaging Camera Sales


Exporting Thermal Cameras, Infrared Cameras or Infrared Sensors to certain countries may be restricted by the United States Government and many fall under “ITAR”, “International Traffic in Arms Regulations”. All ITAR items are designated by the U.S. Department of State.

Some cameras fall under a specific ECCN Codes or an Export Control Classification Number. ECCN items are governed by the U.S. Department of Commerce “Bureau of Industry and Security”. Most countries can purchase uncooled microbolometer based, 9 Hz thermal imaging cameras without restriction. This depends on the sensor size and pixel pitch. For example an ICI 9640 S, 9 Hz 640 x 480 microbolometer camera with 17 um pixel pitch can be exported to most non embargoed countries.


Thermal Cameras with Pixel pitch smaller than 17 um may be an issue. This is determined by the U.S. Department of State. The map below is for informational purposes only, and may not accurately reflect current export or import laws. Most ICI Cameras have a CJ or Commodity Jurisdiction Code for them but some do not. When shipping a camera outside the U.S. it best to be safe and ask as the penalty for getting it wrong can be prison.


All countries designated with the color green are “Wassenaar Agreement” countries and currently able to purchase microbolometer based thermal imaging cameras up to 384x288 pixel resolution and 17 um pixel pitch without restrictions. The Countries on this list change and are updated so make sure before you buy or ship a system. Those marked with red may be considered "banned" countries and restrictions will apply.


Country Policies and Embargoes

The International Traffic in Arms Regulations (ITAR)

Export Control Classification Number (ECCN)


Many countries can receive thermal imaging cameras with restrictions and proper documentation. As the law varies from country to country, please, consult with ICI or your export expert to learn the exact restrictions and documents needed for export, if any.

List of Countries where an Export License is no longer required:

  •     Australia
  •     Austria
  •     Belgium
  •     Bulgaria
  •     Cyprus
  •     Czech Republic
  •     Denmark
  •     Estonia
  •     Finland
  •     France
  •     Germany
  •     Greece
  •     Hungary
  •     Iceland
  •     Ireland
  •     Italy
  •     Japan
  •     South Korea
  •     Latvia
  •     Lithuania
  •     Luxembourg
  •     Malta
  •     Netherlands
  •     New Zealand
  •     Norway
  •     Poland
  •     Portugal
  •     Romania
  •     Slovakia
  •     Slovenia
  •     South Africa
  •     Spain
  •     Sweden
  •     Switzerland
  •     Turkey
  •     United Kingdom

Click Here: To Read More About Government Regulations Concerning Infrared Camera Exports


Critical Technology Assessment: Night Vision Focal Plane Arrays, Sensors and Cameras

NOTE: Buyer will be responsible for any extra charges such as import, tariffs, or duties as provisioned by your local government. For details, please, call us at 1-409-861-0788, or Toll Free at 1-866-861-0788 for international customers, and we will gladly work with you to ensure the correct procedures for your country are followed.

  • Infrared Defined

    What is Infrared?


    Infrared radiation is electromagnetic radiation whose wavelength is longer than that of visible light (400-700 nm), but shorter than that of terahertz radiation (100 µm - 1mm) and microwaves (~30,000 µm). Every object gives off thermal radiation, and this energy can be viewed with an infrared camera.


    • Infrared energy emitted by objects travels at the speed of light which is 186,000 miles per second. Or 300,000 km per second.

    • Infrared energy is a form of light and therefore it obeys all the same laws of visible light.



    What is Infrared Imaging?


    Infrared imaging is the collection, recording, and displaying of light from a scene; can be known as Infrared or IR, Thermal Imaging, FLIR (forward looking infrared), or Thermography. 'Infrared’ refers to light with longer wavelengths than that of visual light, and shows the thermal patterns emitted from, or reflected off of a target; thus, it does not require visual light.



    What is Infrared Radiation?


    Radiation is energy that is radiated or transmitted in the form of waves or particles. Anything NOT at Absolute Zero (-273° C, -459° F) emits infrared radiation, including the sun, icebergs, humans, animals, furniture, etc.


    All infrared cameras and thermometers detect radiant heat, also known as infrared radiation, that increases with molecular activity. As an object becomes warmer, it radiates more energy which an infrared camera can detect in order to create a thermal image or thermogram.



    What is a Thermogram?


    A thermogram is a thermal image made by an infrared camera showing temperature differences in varying colors based on the color palette chosen by a thermographer. It is ONLY a visual depiction of radiated heat, NOT temperature.



    What is Infrared Thermography?


    Infrared Thermography is the discipline concerned with the acquisition, storage and analysis of radiated energy using a thermal infrared imaging system. The resulting images do not show temperature; they only depict radiated energy.


    Infrared Cameras Inc. uses a hue palette to assign colors to molecular activity and an algorithm to allow our IR cameras to "see" temperature.



    What are the Benefits of Infrared Thermography?


    •     Temperature calculations are non-contact
    •     Process does not have to be shut down - must be running
    •     Will not deface or destroy the product
    •     Transient phenomena or moving objects can be studied
    •     Fast response, milliseconds
    •     Temperature calculations of irregular shaped objects
    •     Pattern observation and evaluation
    •     Collection of large amounts of thermal data
    •     Measurement through hazardous atmospheres
    •     Measurement through special IR windows
    •     Data easily stored for post analysis and trending
  • Measurements and Thermodynamics

    What is a Qualitative Infrared Camera?


    • Qualitative cameras do not measure temperature. They simply display temperature differences in a few different palettes including black and white. These infrared cameras or thermal imagers are generally used by law enforcement, home inspectors, or coast guard for a number of purposes.
    • The police use infrared cameras to identify criminal activity at night just like we’ve seen on COPS.
    • Home and building inspectors use these systems to look for moisture intrusion or energy loss in building envelopes.
    • And the coast guard or any other water bound vessel may use infrared for search and rescue or to see through certain weather conditions such as fog or rain.
    • Firefighters also use qualitative cameras to see through smoke and locate survivors in burning buildings.


    What is a Quantitative Infrared Camera?


    • Quantitative cameras can measure temperature. These cameras are technically known as imaging radiometers.
    • Their purpose is to measure the radiant energy coming from a target to identify problem areas in electrical equipment, machinery, rotating equipment, kilns, boilers, and just about any kind of process that you can think of.
    •  We also use quantitative cameras to monitor different types of processes or process equipment, and even the human body.


    What is Temperature?


    • Temperature is a measurement of the average kinetic energy of the vibrating molecules that the temperature measurement device is relating to.
    • Temperature specifies the state of a body with respect to its ability to impart energy to other bodies.


    What is Absolute Zero?


    Theoretical temperature when molecules lose all vibrational kinetic energy. All objects above absolute zero ( -273° C or - 459° F) emit infrared energy.


    What is Heat?


    Heat is energy in transit from areas of higher molecular motion (higher temperature) to areas of lower molecular motion (lower temperature) independent of direction. When all of the molecules have the same kinetic energy we have a state called thermal equilibrium. There is no heat transfer in this state.


    What are the Laws of Thermodynamics?


        • 1st Law

        – Energy must be conserved or exactly accounted for (it can be changed from one form to another form)

        – Heat that flows to an object must go somewhere, it cannot be created or destroyed

        – Energyin = Energyout + Energystored

        • 2nd Law

        – Heat always flows from a point of higher temperature to a point at lower temperature


    What is Conduction?


    Conduction is a point-by-point process of heat transfer. If one part of a body is heated by direct contact with a source of heat, the neighboring parts become heated successively. Thus if a metal rod is placed in a burner, heat travels along the rod by conduction. This may be explained by the kinetic theory of matter. The molecules of the rod increase their energy of motion. This violent motion is passed along the rod from molecule to molecule. In considering the flow of heat by conduction, it is sometimes helpful to compare the flow of heat to the flow of electricity. The temperature difference can be thought of as the pressure, or voltage, in an electrical circuit. The ability of a substance to transfer heat (its thermal conductivity) can be compared to electrical conductivity. When the temperature difference (or voltage) between two points is great, the driving force to move heat (or current) is high. The quantity of heat (or current) transferred will depend upon the temperature difference (or voltage difference) and the resistance to the flow of heat (or current) offered by the conductor.


    What is Convection?


    The method of heat transfer called convection depends upon the movement of the material which is heated. It applies to free-moving substances; that is, liquids and gases. The motion is a result of changes of density that accompany the heating process. Water in a tea kettle is heated by convection. A stove heats the air in a room by convection. When a liquid or gas is heated, its density (mass per unit volume) decreases; that is, it becomes lighter in weight. A warmer volume of gas will rise while a colder, and thus heavier, volume of gas will descend. This process is described as natural convection. A familiar example of natural convection is the circulation of air from a hot-air furnace. When a liquid or gas is moved from one place to another by some mechanical force, the process is known as forced convection. The circulation of air by an electric fan is an example of forced convection.


    What is Emissivity?


    The rate at which infrared energy is emitted by an object compared to that of a Blackbody at the same temperature and in the same wavelength.


    What are Palettes?


    Color palettes are convenient ways for you to see a thermal image. For instance, you may chose to have cold be the color blue, medium yellow and red hot. Or you might want everything black and white with everything over 80°F red. Or you might want cold to be purple and hot to be yellow.


  • Applications and Restrictions

    What application is infrared used in?


    Thermography, building inspections, monitoring & control applications, medical imaging, communications, night vision, infrared photography, Spectroscopy, military, research & development, process control, meteorology, astronomy, art history, biological systems, photobiomodulation, law enforcement, emergency services, military, infrared building inspections, commercial, residential, and industrial. Just to name a few.


    Can you see through walls with an Infrared camera?


    Unlike the movies, with infrared, we cannot see through walls. We can only see temperature differences present due to the conduction, convection, or radiation of thermal energy. While shorter infrared waves can be seen as colors, as infrared waves get longer they give off radiation in the form of thermal energy. Infrared waves are considered to be energy. Infrared cameras look at radiated energy from the first 1/1000” of the surface.


    What do Infrared cameras see?


    Infrared cameras only see the emitted or radiant energy from the 1st one thousandth of an inch of the surface of most solids and liquids.


    Can Infrared measure temperature?


    • Infrared cameras see heat in the form of radiant energy.
    • The Thermographer measures the temperature of a target. You have to put the proper data into the camera in order to get accurate temperature measurements.
    • This means that setting up your camera before an inspection is important. It is also important to realize that you will be changing some of these settings in your camera during your inspection. (Of course this depends on the scope of equipment that you’re inspecting.)


    What are the industrial and commercial applications of infrared thermography?


    This technique has many applications such as industrial electrical systems, furnaces, refractory, locating wet areas in large flat roofs, identifying heat loss in buildings, security and surveillance, and medical observations. Since you are looking at heat pictures, abnormal patterns often mean specific things: a high resistance electrical connection is hotter than other connections under the same conditions, missing insulation in a building wall will show up as a warm area on the exterior, a wet area on a flat compound roof is cooler than the area around it.


    What are the differences between night vision and thermal imaging?


    The main difference between night vision and thermal imaging is the ability to see in total darkness. Night vision utilitzes existing light sources and amplifies them, while thermal imaging is actually reading the infrared radiation coming from an object, regardless of any visible light source, and a trained thermographer can utilize this information to get accurate temperature measurements. Read more...


    What is the camera resolution?


    At Infrared Cameras Inc., we offer a variety of resolutions with our cameras. The resolution of an infrared camera can be compared to a television or computer monitor resolution. The larger the resolution, the more pixels on the screen. The more pixels you have, the finer the detail of the image.






























Absolute Zero - The temperature that is zero on the Kelvin or Rankine temperature scales. The temperature at which a material is at its lowest energy state.


Absorptivity,  a [Absorptance] - The proportion (as a fraction of 1) of the radiant energy impinging on a material’s surface that is absorbed into the material. For a blackbody, this is unity (1.0). Technically, absorptivity is the internal absorptance  per unit path length. In thermography, the two terms are often used interchangeably.


Accuracy [of Measurement] - The maximum deviation, expressed in % of scale or in degrees Celsius or degrees Fahrenheit, that the reading of an instrument will deviate from an acceptable standard reference.


Ambient Operating Range - Range of ambient temperatures over which an instrument is designed to operate within published performance specifications.


Ambient Temperature - Temperature of the air in the vicinity of the target (target ambient) or the instrument (instrument ambient).


Ambient Temperature Compensation - Correction built into an instrument to provide automatic compensation in the measurement for variations in instrument ambient temperature.


Anomaly - Any irregularity, such as a thermal anomaly on an otherwise isothermal surface. Any indication that deviates from what is expected.


Apparent Temperature - The target surface temperature indicated by an infrared point sensor, line scanner or imager before temperature corrections are made.


Artifact - A product of artificial character due to extraneous agency; an error caused by an uncompensated anomaly. In thermography, an emissivity artifact simulates a change in surface temperature but is not a real change. A hot solar reflection or a cold reflection due to narcissus would be examples of artifacts.


Atmospheric Windows [Infrared] - The spectral intervals within the infrared spectrum in which the atmosphere transmits radiant energy well (atmospheric absorption is a minimum.). These are roughly defined as 3-5 µm and 8-14 µm.





Background Temperature, Instrument - The apparent temperature of the radiant energy impinging on an object that is reflected off the object and enters the instrument. Originates from the scene behind and surrounding the instrument, as viewed from the target. The reflection of this background appears in the image and affects temperature measurements. Good quality quantitative thermal sensing and imaging instruments provide a means for correcting measurements for this reflection.


Background Temperature, Target - Apparent ambient temperature of the scene behind and surrounding the target, as viewed from the instrument. When the FOV of a point sensing instrument is larger than the target, the target background temperature will affect the instrument reading. Also called surroundings temperature, foreground temperature.


Blackbody, Blackbody Radiator - A perfect radiator, one that radiates the maximum number of photons in a unit time from a unit area in a specified spectral interval into a hemisphere that any body in thermodynamic equilibrium at the same temperature can radiate. It follows that a blackbody absorbs all radiant energy impinging on it and reflects and transmits none; thus a surface with emissivity of unity (1.0).


Blackbody Curves - Plots of radiant power spectral exitance (W/m²/mm) vs. wavelength for various temperatures according to the Planck equation. These curves show the maximum amount of energy at any given wavelength that can be radiated by an object due solely to its temperature. Also called Planck curves.


Bolometer, Infrared [Micro-Bolometer] - A type of thermal detector commonly used in uncooled radiometers.



Calibration - Checking and/or adjusting an instrument such that its readings agree with a standard. Calibration removes instrument systematic error and quantifies the instrument random error.


Calibration Accuracy - The accuracy, to which a calibration is performed, usually based on the accuracy and sensitivity of the instruments and references used in the calibration.


Capacitance, Thermal - This term is used to describe heat capacity in terms of an electrical analog, where loss of heat is analogous to loss of charge on a capacitor. Structures with high thermal capacitance lose heat more slowly than those structures with low thermal capacitance.


Capacity, Heat - The heat capacity of a material or structure describes its ability to store heat. It is the product of the specific heat (c­­­p) and the density (r) of the material. This means that denser materials generally will have higher heat capacities than porous materials.


Celsius [Centigrade] - A temperature scale based on 0°C as the freezing point of water and 100°C as the boiling point of water at standard atmospheric pressure; a relative scale related to the Kelvin scale [0°C = 273.12 K. 1 C° (DT) = 1 K. (DT)].


Color - A term sometimes used to define wavelength or spectral interval, as in two-color radiometry (meaning a method that measures in two spectral intervals); also used conventionally (visual color) as a means of displaying a thermal image, as in color thermogram.


Conductance, Thermal - A measure of the ability of a material of defined thickness and cross-sectional area to conduct heat. Related to the material property, thermal conductivity. The inversed of thermal resistance (C = 1/R).


Conduction, Thermal - The only mode of heat flow in solids, but can also take place in liquids and gases. It occurs as the result of atomic vibrations (in solids) and molecular collisions (in liquids and gases) whereby energy is transferred from locations of higher temperature to locations of lower temperature.


Conductivity, Thermal,  [K] -  A material property defining the relative capability to carry heat by conduction in a static temperature gradient. Conductivity varies slightly with temperature in solids and liquids and with temperature and pressure in gases. It is high for metals (copper has a K of 380 W/m-°C) and low for porous materials (concrete has a K of 1.0) and gases.


Convection - The form of heat transfer that takes place in a moving medium and is almost always associated with transfer between a solid (surface) and a moving fluid (such as air), whereby energy in transferred from higher temperature sites to lower temperature sites.



Delta T - the temperature difference between two targets usually of comparable targets under comparable conditions.


Detector, Infrared - A transducer element that converts incoming infrared radiant energy impinging on its sensitive surface into a useful electrical signal.


Diffuse Reflector - The maximum deviation, expressed in % of scale or in degrees Celsius or degrees Fahrenheit, that the reading of an instrument will deviate from an acceptable standard reference.


Diffusivity, Thermal, [a] - (Note: same symbol as absorptive, may be confusing.) The ratio of conductivity (k) to the product of density (r) and specific heat (Cp) [a = k/rCp cm² sec­‑1]. The ability of a material to distribute thermal energy after a change in heat input. A body with a high diffusivity will reach a uniform temperature distribution faster than a body with lower diffusivity.


D* [Detectivity Star] - Sensitivity figure of merit of an infrared detector--detectivity expressed inversely so that higher D*s indicate better performance; taken at specific test conditions of chopping frequency and information bandwidth and displayed as a function of spectral wavelength.


Direct Thermography - Thermal imaging and measurement of a surface whose thermal signature is, or is directly affected by the target of concern. That is, the target of concern has little or no thermal insulation between it and the surface measured.


Display Resolution, Thermal - The precision with which an instrument displays its assigned measurement parameter (temperature), usually expressed in degrees, tenths of degrees, hundredths of degrees, etc.




Effective Emissivity [e] - (also called emittance, but emittance is a less preferable term because it was formerly used to describe radiant exitance). - The measured emissive value of a particular surface under existing measurement conditions (rather than the generic tabulated value for the surface material) that can be used to correct a specific measuring instrument to provide a correct temperature measurement.


Effusivity, Thermal [e] - A measure of the resistance of a material to temperature change

E = ÖkrCp cal Cm2 °C-1 sec½


                K = thermal conductivity

                r = bulk density

                C­­­­­­­­p = specific heat


Emissivity [e] - The ratio of a target surface’s radiance to that of a blackbody at the same temperature, viewed from the same angle and over the same spectral interval; a generic look-up value for a material. Values range from 0 to 1.0. Alternatively, the ratio of a flat, optically polished, opaque target surface radiance to that of a blackbody at the same temperature, viewed from the same angle and over the same spectral interval. The latter definition characterizes the property of the material. When used this way, emittance is used to characterize the material when it is other than flat, optically polished and opaque.


Emittance [e] - The ratio of a target surface’s radiance to that of a blackbody at the same temperature, viewed from the same angle over the same spectral interval; a generic look-up value for a material. Values range from 0 to 1.0.


EMI/RFI Noise - Disturbances to electrical signals caused by electromagnetic interference (EMI) or radio frequency interference (RFI). In thermography, this may cause noise patterns to appear on the display.


Environmental Rating - A rating given an operating unit (typically an electrical or mechanical enclosure) to indicate the limits of the environmental conditions under which the unit will function reliably and within published performance specifications.


Exitance, Radiant [Also Called Radiosity] - Total infrared energy (radiant flux) leaving a target surface. This is composed of radiated, reflected and transmitted components. Only the radiated component is related to target surface temperature.



Fahrenheit - A temperature scale based on 32°F as the freezing point of water and 212°F as the boiling point of water at standard atmospheric pressure; a relative scale related to the Rankine scale [0°F = 459.67.R; 1 F° (DT) = 1 R (DT)].


Field of View [FOV] - The angular subtense (expressed in angular degrees or radians per side if rectangular, and angular degrees or radians if circular) over which an instrument will integrate all incoming radiant energy. In a radiation thermometer this defines the target spot size; in a scanner or imager this defines the scan angle or picture size or total field of view (TFOV).


Fiber Optic, Infrared - A flexible fiber made of a material that transmits infrared energy, used for making non-contact temperature measurements when there is not a direct line of sight between the instrument and the target.


Filter, Spectral - An optical element, usually transmissive, used to restrict the spectral band of energy received by an instrument’s detector.


Flame Filter - A filter of a specific waveband used to minimize the effects of flame, enabling the IR camera to “see” through the flame. The specific waveband is a region where the transmittance of flame approaches unity. Center wavelengths are typically 3.9 mm for shortwave instruments and 10.6 mm for longwave.


Focal Plane Array [FPA] - A linear or two-dimensional matrix of detector elements, typically used at the focal plane of an instrument. In thermography, rectangular FPAs are used in “staring” (non-scanning) infrared imagers. These are called IRFPA imagers.


Focal Point - The point at which the instruments optics image the infrared detector at the target plane. In a radiation thermometer, this is where the spot size is the smallest. In a scanner or imager, this is where the instantaneous field of view (IFOV) is smallest.


Foreground Temperature [See Instrument Ambient Background] - Temperature of the scene behind and surrounding the instrument as viewed from the target.


Frame Repetition Rate - The time it takes an infrared imager to scan (update) every thermogram picture element (pixel); in frames per second.


Full Scale - The span between the minimum value and the maximum value that any instrument is capable of measuring. In a thermometer, this would be the span between the highest and lowest temperature that can be measured.




Graybody - A radiating object whose emissivity is a constant value less than unity (1.0). over a specific spectral range.



Heat Transfer- The movement of heat from one point to another by conduction, convection and/or radiation.


Hertz [Hz] - A unit of measurement of signal frequency; 1 Hz = cycle per second.


Herschel, Sir William - Discovered infrared in 1800.



Imager, Infrared - An infrared instrument that collects the infrared radiant energy from a target surface and produces an image in monochrome (black and white) or color, where the gray shades or color hues correspond respectively to target exitance.


Image Display Tone - Gray shade or color hue on a thermogram.


Image Processing, Thermal - Analysis of thermal images, usually by computer; enhancing the image to prepare it for computer or visual analysis. In the case of an infrared image or thermogram, this could include temperature scaling, spot temperature measurements, thermal profiles, image manipulation, subtraction and storage.


Imaging Radiometer - An infrared thermal imager that provides quantitative thermal images.


Indirect Thermography - Thermal imaging and measurement of a surface which is indirectly affected by the target of concern. That is, the target of concern is thermally decoupled from the surface due to thermal insulation, such as an air gap or a radiant barrier.


Indium Antimonide [InSb] - A material from which fast, sensitive photo-detectors used in infrared scanners and imagers are made. Such detectors usually require cooling while in operation.


Inertia, Thermal - See thermal effusivity.


Infrared [IR] - The infrared spectrum is loosely defined as that portion of the electromagnetic continuum extending from the red visible (0.75 mm  to about 1,000 mm) . Because of instrument design considerations and the infrared transmission characteristics of the atmosphere, however, most infrared measurements are made between 0.75 and 20 mm.


Infrared Focal Plane Array [IRFPA] - A linear or two-dimensional matrix of individual infrared detector elements, typically used as a detector in an infrared imaging instrument.


IRFPA Imager or Camera - An infrared imaging instrument that incorporates a two-dimensional IRFPA (focal plane array) and produces a thermogram without mechanical scanning.


Infrared Radiation Thermometer - An instrument that converts incoming infrared radiant energy from a spot on a target surface to a measurement value that can be related to the temperature of that spot.


Infrared Thermal Imager - An Instrument or system that converts incoming infrared radiant energy from a target surface to a thermal map, or thermogram, on which color hues or gray shades can be related to the temperature distribution on that surface.


Instantaneous Field of View [IFOV] - The angular subtense (expressed in angular degrees or radians per side if rectangular and angular degrees or radians if round) found by the ratio of the detector dimension divided by the instrument focal length; the projection of the detector at the target plane. In a radiation thermometer this defines the target spot size; in a line scanner or imager it represents one resolution element in a scan line or thermogram and is a measure of spatial resolution.


Isotherm - A pattern superimposed on a thermogram or on a line scan that includes or highlights all points that have the same apparent temperature.



Kelvin - Absolute temperature scale related to the Celsius (or Centigrade) relative scale. The Kelvin unit is equal to 1 C°; 0 Kelvin = -273.16°C; the degree sign and the word “degrees” are not used in describing Kelvin temperatures.


Kirchoff’s Law - In thermal equilibrium the absorbtivity of an opaque surface equals its emissivity (a = e).



Laser Pyrometer - An infrared radiation thermometer that projects a laser beam to the target, uses the reflected laser energy to compute target effective emissivity and automatically computes target temperature (assuming that the target is a diffuse reflector)---not to be confused with laser-aided aiming devices on some radiation thermometers.


Latent Heat - Also called “hidden heat” as heat is added or removed without changing the temperature. The amount of heat required (or released) for a change of phase from solid to liquid and liquid to gas (or vice versa). The latent heat of vaporization is the amount of heat required to change one gram of liquid to vapor without change of temperature. The latent heat of fusion is the amount of heat to melt  one gram of solid to liquid with no temperature change.


Line Scan Rate - The number of target lines scanned by an infrared scanner or imager in one second.


Line Scanner, Infrared - An instrument that scans a field of view along a straight line at the target plane in order to collect infrared radiant energy from a line on the target surface, usually done by incorporating one scanning element within the instrument. If the target (such as a sheet or web process) moves at a fixed rate normal to the line scan direction, the result can be displayed as a thermogram.



Measurement Spatial Resolution, IFOVmeas - The smallest target spot size on which an infrared imager can produce a measurement, expressed in terms of angular subtense (mrad per side). The slit response function (SRF) test is used to measure IFOVmeas.


Medium, Transmitting Medium - The composition of the measurement path between a target surface and the measuring instrument through which the radiant energy propagates. This can be vacuum, gaseous (such as air), solid, liquid or any combination of these.


Mercury Cadmium Telluride MCT [HgCdTe] - A material used for fast, sensitive infrared photo-detectors used in infrared sensors, scanners and imagers that requires cooled operation.


Micro-Cooler - A small, palm size cooler based on the Stirling cycle that cools an infrared detector or focal plane array to liquid nitrogen temperature (77K).


Micron [Micrometer] [m or, mm ] - One millionth of a meter; a unit used to express wavelength in the infrared.


Milliradian [MRAD] - One thousandth of a radian (1 radian = 180°/p); a unit used to express instrument angular field of view; an angle whose tangent is equal to 0.001; 1 mrad = 0.05729578°)


Minimum Resolvable Temperature [Difference], MRT(D) - Thermal resolution; thermal sensitivity - the smallest temperature difference that an instrument can clearly distinguish out of the noise, taking into account target size and characteristics of the display and the subjective interpretation of the operator. The limit of MRTD is MDTD (minimum detectable temperature difference). MDTD is the MRTD of an extended source target, that is, a target large enough to be fully resolved by the instrument.


Modulation - In general, the changes in one wave train caused by another; in thermal scanning and imaging, image luminant contrast; (Lmax - Lmin)/(Lmax + Lmin).


Modulation Transfer Function [MTF] - A measure of the ability of an imaging system to reproduce the image of a target. A formalized procedure is used to measure MTF. It assesses the spatial frequency resolution of a scanning or imaging system as a function of distance to the target.



Night Vision - The ability to see in low light conditions. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range. Humans have poor night vision compared to many animals, in part because the human eye lacks a tapetum lucidum.


Noise Equivalent Temperature [Difference], NET[D] - The temperature difference that is just equal to the rms noise signal; a measure of thermal resolution; (thermal sensitivity), but not taking into account target size, characteristics of the display and the subjective interpretation of the operator.


NIST, NIST Traceability - The National Institute of Standards and Technology (formerly NBS). Traceability to NIST is a means of ensuring that reference standards remain valid and their calibration remains current.


Non-Gray body - An object whose emissivity varies with wavelength over the wavelength interval of interest. A radiating object that does not have a spectral radiation distribution similar to a blackbody; also called a “colored body” or “realbody”. Glass and plastic films are examples of non-graybodies. An object can be a graybody over one wavelength interval and a non-gray body over another.



Objective, Objective Lens - The primary lens of an optical system, on an infrared instrument, usually the interchangeable lens that defines the total field of view.


Opaque - In thermography, an opaque material is one that does not transmit thermal infrared energy, ( t = 0).


Optical Element, Infrared - Any element that collects, transmits, restricts or reflects infrared energy as part of an infrared sensing or imaging instrument.


Oversampling - Collecting samples at a rate higher than the Nyquist critical frequency, fc = 1/(2D), where D is the sampling interval. Applies to both time and spatial domains.



Peak - Hold - A feature of an instrument whereby an output signal is maintained at the peak instantaneous measurement for a specified duration.


Photo-Detector [Photon Detector] - A type of infrared detector that has fast response, (on the order of microseconds), limited spectral response and usually requires cooled operation; photo-detectors are used in infrared radiation thermometers, scanners and imagers.


Pixel - Abbreviation for picture element. In infrared technology a pixel is a focal plane array element, for scanning systems is defined by the IFOV, for spot radiometers by FOV.


Planck, Max Karl Ernst Ludwig - German physicist who incorporated quantum physics into the blackbody spectral radiance equation, giving rise to blackbody curves.


Pyroelectric Detector - A type of thermal infrared detector that acts as a current source with its output proportional to the rate of change of its temperature.


Pyroelectric Vidicon [PEV], Also Called Pyrovidicon - A video camera tube with its receiving element fabricated of pyroelectric material and sensitive to wavelengths from about 2 to 20 mm; used in infrared thermal viewers.


Pyrometer - Any instrument used for temperature measurement. A radiation or brightness pyrometer measures visible energy and relates it to brightness or color temperature. An infrared pyrometer measures infrared radiation and relates it to target surface temperature.



Qualitative Measurement - The process of obtaining and interpreting thermal images based on thermal contrast in order to identify anomalies; the purpose is more to determine where a temperature difference exists than what the temperature difference is between the target and its surroundings.


Quantitative Measurement - The process of obtaining thermal images with correct temperature readings. Especially useful in situations when the exact temperature or temperature difference of the target determines whether it falls in or out of a determined criteria or range of acceptability. Also important to R & D and process control situations.



Radian - An angular measurement equal to the ratio of the arc length of a circle to its radius. The circumference of a circle is 2p times the radius. Thus p radians = 180 degrees, and 1 radian = 57.29578 degrees.


Radiation, Thermal - The mode of heat flow that occurs by emission and absorption of electromagnetic radiation, propagating at the speed of light. Unlike conductive and convective heat flow, it is capable of propagating across a vacuum. The form of heat transfer that allows infrared thermography to work since infrared energy travels from the target to the detector by radiation.






Infrared Imaging (IR) News, Articles, and Tips

Gary Strahan, Founder of Infrared Cameras Inc., on CNN (August 4, 2014) discussing how ICI’s thermal imaging cameras and technological software may be used to limit a potentially infected person from spreading a viral infection, like Ebola, globally. Early symptoms of the Ebola virus include sudden onset of fever. View the entire CNN News video here.

Thermal Imaging cameras can measure a person's body temperature to the hundredth of a degree. ICI's cameras have already been used in airports in China during the SARS outbreak, and, now, the company is hoping to use them to help detect fevers in people in West Africa to help prevent the spread of the Ebola virus. Learn more about: ICI Fever Detection System here.

Infrared Cameras Inc.  is one of only two American businesses that can sell infrared cameras overseas to fight against the deadly Ebola disease, they could have screened Thomas Duncan before he left Liberia.


The FDA has approved Infrared Cameras Inc., a Beaumont-based company, to sell its devices overseas. View the entire KBMT 12 News video here.

A Beaumont company manufactures a device it is using to help countries stop the spread of the deadly Ebola virus, which has claimed almost 900 lives in West Africa since March.


Infrared Cameras Inc. makes thermoscan cameras, used at airports to screen passengers for fever and prevent the spread of infections, including Ebola. Read the entire Beaumont Enterprise news article here.