All You Need To Know About Thermal Cameras

Everything About Thermal Cameras

Thermal cameras are a godsend. In an era when the coronavirus has changed the course of history for the worse, sending chills and untold fear to everyone on the planet, thermal imaging technology rose to the occasion. Indeed, it is playing a central role in containing the seemingly unstoppable advance of humanity’s invisible scourge: COVID-19.

 

For a decade or so, infrared imaging technology settled within the spheres of the technical crews — the firefighters and the home inspectors who both rolled with it to deliver quality work. Today, however, a thermal camera has become a household word. As security personnel and mall operators line up thermal cameras in their entrances to protect their establishments from the virus, most everyone on the planet agrees. The superiority of infrared imaging technology is a treasure find.

 

And true enough, looking into the essence of a thermal camera opens up to a world of endless possibilities for you. Not just to detect fever without a single hair of your skin ever touching another human. But in other key aspects of your everyday living.

 

Think of it as your third eye. With a thermal camera doing your bidding, you need not be in the driver’s seat driving blind in precarious situations. You can see through foggy roads even in the dead of the night. Even better, you need not be left at the mercy of hidden electrical faults and surreptitious attacks of vermins and insects right in your home. You’re pretty much covered. Read on to find out how your life can change for the better with an infrared camera in your hand.

What is a Thermal Camera?Normal visible image with thermal image side by side

 A thermal camera is a camera equipped with special sensors that can detect varying degrees of heat or thermal energy and turn it into visible light. By doing so, firefighters can determine the seat of the fire and areas of heat even in complete darkness with the presence of heavy smoke or fog.

Know that a thermal camera, dubbed also the infrared camera, is not dependent on the presence of light to form the heat image or thermogram. Meaning, you would see the different energy emissions of objects even in the dark when you look into one. The more heat energy an object emits, the lighter it is in the picture. And conversely, the lesser heat energy, the darker the picture becomes.

The principles behind the thermal camera are based on the work done by Sir William Herschel (1728 - 1832) a budding German astronomer who first discovered the existence of infrared radiation. Looking into the nature of light to study the heavens above, Herschel stumbled upon an invisible yet heated area in the ES or electromagnetic spectrum.

With wavelengths longer than visible light and yet shorter than the microwave, the invisible heat energy discovered by Herschel was dubbed “radiant heat”. Later, it was called infrared light as it resided below the red color of the rainbow, or the visible portion of the ES.

Another prominent astronomer, one from America, Samuel Pierpoint Langley (1834 - 1906) picked up the cudgels of thermal technology work from where Herschel left off. In a sense, the American scientist (founder of the Smithsonian Astrophysical Observatory)  moved the needle of thermal imaging technology with his invention of the bolometer.

It’s safe to say, the bolometer (invented in 1878) is thermal tech’s first big break. In essence, a bolometer is a radiant-heat detector made up of:

  • two thin metal strips
  • a Wheatstone bridge
  • Battery
  • Galvanometer ( to measure electrical current)

Capable of detecting temperature differences up to a hundred-thousandth of a degree Celcius (0.00001 C), a bolometer provided Langley to study the sun’s light rays, better known as solar irradiance.

Thanks to Langley’s invention, most of the thermal cameras available in the market today use bolometers to operate.

To note, the application of a thermal camera has grown steadily over the years. Where before infrared technology was used in the military and later in firefighting, today it has reached consumer consciousness like never before.

This is largely due to the fact that thermal cameras have become the standard tool in COVID-19 prevention. As the virus spread worldwide claiming millions of lives, the infrared camera’s ability to determine feverish temperatures from a safe distance cannot be overemphasized in its usefulness. Chances are, establishments and government institutions all over America line up infrared technology in their entrances today.

Can a thermal camera see through walls?

No, a thermal camera cannot see through walls but it can detect strong thermal images that affect the walls. To understand thermal cameras we must not define them in the terms of traditional cameras that have become a standard feature in our smartphones. Remember thermal cameras do not see objects; rather they’re designed to detect heat.

So if you want to use the thermal camera to see what’s on the other side of the wall, it’s not possible. But if you want to know if there’s a big fire on the other side of the wall, infrared imaging is bound to detect it.

We’re assuming the wall is thick. So if the heat energy on the other side is so strong that it affects the wall as a whole and changes its overall temperature, that rising heat signature will register in the infrared device.

As such, thermal imaging can also go through fog, heavy smoke, or even total darkness. This means it can give you an accurate heat reading even when there is little to no light available.

Apparently,  these cameras have saved countless lives in disaster zones - especially in fires.  It gives firefighters critical advanced information. A thermal camera on their helmet allows them to see the seat of the fire. That way they can extinguish a fire incident faster and manage the fire better.

Most importantly, they can locate trapped individuals via a thermal camera. Had there been more thermal cameras available in America, there would be a lot lesser number of casualties during past disasters - Sept 11, 2001, most notably.

On a side note, this shows how an IR camera can protect your precious abode from possible dangers - such as a fire.

How Can a Thermal Cameras Improve My Life?

Yes, your life would be a lot safer with a thermal camera at your beck and call. That’s especially true now that the virus is still at large.

  • 423,000 Americans: Nearly half a million have succumbed to the virus as of January 2021.
  • 100 million: Total confirmed COVID-19 infected cases worldwide

Think how safe you’d be if you can detect anyone near you if he or she has a fever? All the detection is done from a safe distance. And a handy thermal camera can do that for you.

And then some. 

Every year, over 31,385 fog-related crashes happen on American soil. That’s 511 deaths on average year in year out. With a thermal camera on your vehicle, you’d be a lot safer even when driving through foggy weather.  Indeed. Better safe than sorry.

Plus, thermal imaging cameras can protect you from the prospects of a fire. Faulty home wiring is a leading cause of electrical fires - and unnecessary deaths. With a thermal camera, you can detect overheating electrical wiring as easy as A, B, and C.

And that should include your HVAC and water system. So you are kept away from furnace-ignited fires and overheating ACs. Or for that matter water leaks.  For now, you can check all these things, without having to open pipes or physically eyeball every nook and cranny.

Even better, thermal cameras have a host of other popular uses. Some of which are impressive such as its ability to detect the birth of a new star. In table form, we have:

 

Thermal Camera Popular Uses

 

Government

Personal Use

Industry

Health/Science

Others

Firefighting

Indoor Air Quality

PCB checking (printed circuit board)

Disease control

(SARS, Bird Flu, Coronavirus)

Animal Rescue

Airport checks

Gas leak detection

Premature product failure checking

Wildlife Surveys

Hydraulic systems

Drug busts

Termite inspection

Power Usage

Skin temperature

Aircraft maintenance

Counterfeit detection

HVAC inspection

Phase supply

Musculoskeletal Inspection

Hydronic heating

Surveillance

Water leakage inspection

Underfloor heating

Circulation Problems

Greenhouses

Search and Rescue

Intruder Alert

Solar panels

Cancer detection

Welding

Maritime navigation

Unwanted Pests

Pumps and motors

Horse/pet treatment

Insurance Claims

Military/Defense

Hunting

Bearings/conveyor belts

Fever detection

Hot water pipes

 

  1. Can thermal cameras detect disease?

To a large degree, a thermal camera can be a vital tool in determining the presence of disease symptoms. For instance, thermography or the use of a thermal camera can detect the abnormal changes in the skin’s temperature of a woman’s breast predicting cancer.

Some of the abnormal health conditions that thermal camera can be a great lift:

  • Breast cancer
  • Arthritis
  • Muscle inflammation
  • Repetitive strain injury
  • Muscular pain
  • Blood circulatory issues
  • Infectious skin disease

The ability of thermal cameras to determine abnormal heat signatures makes it a vital tool in the early detection of diseases. However, health diagnostic tools will have to be deployed to confirm the formation of a health issue.

Moreover, farmers can also benefit greatly from thermal cameras. Hot hooves, for instance, is a surefire sign of a sick cow. Detecting such a condition early can save the livestock.

Also, thermal imaging has been instrumental in preventing the spread of disease  - H1N1 and Ebola virus globally for instance. As thermal cameras detect the rise in body temperature, people affected by these viruses who are marked by high fever can be prevented in the airport from entering the country. This without personnel even touching them directly.

Thermal Camera vs Standard Camera?

Right from the get-go, know that thermal cameras work differently from the traditional camera we know. They are not actual cameras in the strict sense of the word. They are more like sensors - sensing heat.

A camera sees visible light but can’t detect heat. Conversely, a thermal camera detects heat but won’t see visible light in the traditional sense. Thus, it would be easy to understand why the pictures produced by a thermal camera are totally different from those taken from a smartphone. Or via a standard cam.

The good news is technology is getting better. For instance, these days you can grab a thermal camera that can give you a lot closer to a photo finish. PerfectPrime’s hot-seller IR0018 is one perfect example.

For a thermal camera, the greater the thermal emission (the hotter the source), the closer the image displayed will be to white. On the other end of the scale, the lower the thermal emission (the colder the source), the closer the image displayed will be to blue.

Moreover, you can easily see clearly the differences in the distance in a standard picture. But not on a thermal camera. Instead,  you see the thermal. The colors produced depend on the level of “hotness” of the objects being observed.

Note: Thermal cameras are also known as IR (Infra-red) cameras. That’s because these detect infrared waves, waves that are below visible red light in the electromagnetic spectrum. Infra is the Latin word for below. Also, another term for a thermal camera is thermal imaging camera.

How Do Thermal Cameras Work? how a thermal camera works

Thermal cameras, by design, detect the temperature by their ability to recognize and capture varying levels of infrared energy. Take note that all objects on the planet, even a cold block of ice, emit varying degrees of infrared radiation. Only half of the sun’s energy arrives on the planet in visible light; the other half is ultraviolet and infrared.

A thermal camera harbors a special lens that allows the device to detect the thermal emission from all the different sources within its view. With the use of thermal detectors (e.g., microbolometers) the device can capture infrared radiation. Think of a microbolometer as a simple sensor that is capable of absorbing thermal radiation changing resistance as a result. The micro change in resistance can be measured to determine the strength of the infrared radiation.

Each pixel produced in the final image has one microbolometer. Then the data from the microbolometer is converted to its apt color image. All that limited space is the reason why thermal has a much lower resolution compared to a smart TV.

The process is pretty quick - lasting for a fraction of a second. In such a short span of time, as much information as thousands of detailed points is collected and processed. The thermogram is then turned into electrical impulses which will finally be shown - directed to the display screen in the infrared spectrum.

How Accurate Are Thermal Cameras?

The degree of accuracy will often depend on the specification of the thermal camera and the design. The most significant factor to this is the frame rate and whether it’s an un-cooled or cooled thermal camera. Cooled devices are the most sensitive thermal camera types capable of detecting subtle differences in temperature. However, they much more pricey.

Speaking of thermal camera accuracy,  checking out the PerfectPrime IR0280H fever detection thermal camera would be wise. It’s the world’s first handheld camera with an accuracy level of 0.3°C (0.6°F). This makes it a more accurate tool in fever detection.

What Are The Main Types of Thermal Camera?

The two most common types of thermal cameras are uncooled and cooled.

The un-cooled versions are the ones seen all over the market. The system inside un-cooled devices operate at room temperature, are often completely quiet, and can start immediately.

The cooled version is cryogenically cooled below 32°F within a sealed container. The process of cooling the system enables a much higher thermal sensitivity and much clearer thermal resolution. In comparison, the accuracy for a cooled thermal camera is 0.2°F (0.1°C) from over 1000ft away. However, with such an advanced design, the price also climbs steeply.

What is Thermal Resolution?

Thermal resolution determines how clear the thermal image is on your camera. The higher this number the clearer the details are. Typically, a resolution is measured in pixels - given in the form of number x number (e.g., 32 x 32). The first number represents horizontal clarity and the second number, vertical clarity.

To give a rough idea about resolution:

  • thermal resolution up to 10,000 pixels is usually considered the low resolution;
  • 10,000 - 100,000 pixels medium resolution;
  • and beyond 100,000, of high resolution.

It’s essential then that you choose the right gadget for your needs. Input from experts could be timely in this regard.

ULTRA RESOLUTION IMAGES - 320 x 240 Thermal resolution totaling 76,800 pixels. This thermal camera captures every little thermal detail that’s essential for many applications.

PROFESSIONAL TOOL - Home inspectors, site or maintenance operators get great value from this thermal camera in diagnosing heat issues and generating detailed reports.

COMPACT DESIGN - Carry this thermal camera with you anywhere you go as it will conveniently and neatly fit into your shirt pocket, back pocket and free your hands to carry other equipment.

4GB INTERNAL MEMORY - Integrated SD card that will store your captured images as JPG files and operate as a USB drive once connected to any computer.

EXTRA FEATURES - Realign thermal overlays with image registration or switch up the color palettes that best display the thermal signature in your application for accurate and reliable results.

How to Choose a Thermal Camera

It’s not unusual for a buyer to look at the price tag and decide at once if the thermal camera on hand is the right choice or not. And while quality should be a top consideration in buying, the first question you should ask is one about purpose.

Specifically, you need to know if a particular thermal camera set can serve your purpose. This requires due diligence on your part. From the onset, you are well aware of your reason for buying the infrared camera.  What particular application are you planning to use it for? Only when you are well aware of these circumstances will you be able to narrow down your choices.

GENERAL BUYER:

First up, know that there are two major factors to consider when buying a thermal camera in terms of specifications. These are:

  • thermal sensitivity
  • detector resolution

Of course, this is apart from the quality and the price considerations.

Detector resolution is simply the number of pixels a particular thermal imaging camera model can have in a frame. The rule of the game is the more pixels it carries, the greater the image quality will be. What that means is if you’re gunning for a more refined thermal audit you need a thermal cam with more pixels. An example would be looking into PCB or printed circuit board industrial applications.

You can equate this with your smart TV or your social media graphic pictures. So what are the standard detector resolutions? These are:

  • 160 x 120
  • 320 x 240
  • 640 x 480

A 160 x 120 will give you a clarity of 19,200 pixels. If you’re astounded at how we arrive at that figure, it’s just a matter of multiplication. While a 640 x 480 will churn out 307,200 pixels — higher resolution.

Now, let’s talk about thermal sensitivity. When you’re looking into minute changes in temperature, you need higher thermal sensitivity. By definition, thermal sensitivity is the ability of your thermal camera to detect the smallest degree of changes in temperature.

Therefore a thermal camera with thermal sensitivity of  0.05° will be able to distinguish two surfaces with a 0.05° difference in their thermal heat. Meaning, you’d be able to determine the cooler and hotter surface as different hues of color will manifest.

Lastly, check out the temperature range of your particular model in question. The rule of thumb is to allow ample leeway so you don’t run into the infrared camera’s built-in limits. As a general rule, a thermal camera with -4°F to 2,192°F is a good catch.

SPECIALIST BUYER:

If you’re buying a thermal imaging camera for purposes far beyond the usual homeowner’s needs, then you will have to dig deeper into the mechanics of the device.

For starters, know that infrared radiation is but a portion of the electromagnetic spectrum or the whole spectrum of light energy. It has its own peculiarities that are unique to its wavelength. As photon energy, infrared is far weaker compared to Gamma rays or X-rays. In table form:

Name

Wavelength

Frequency (Hz)

Photon Energy (eV)

Gamma-ray

< than 0.01 nm

> than 30 EHz

> than 124 keV

X-ray

0.01 nm - 10 nm

30 EHz - 30 PHz

124 keV -  124 eV

Ultraviolet

10 nm - 400 nm

30 PHz - 790 THz

124 eV - 3.3 eV

Visible light (rainbow)

400 nm - 700nm

790 THz - 430 THz

3.3 eV - 1.7 eV

Infrared

700 nm - 1mm

430 THz - 300 GHz

1.7 eV - 1.24 eV

Microwave

1 mm - 1 meter

300 GHz - 300 MHz

1.24 meV - 1.24µeV

Radio

1 mm - 10,000 km

300 MHz - 30 Hz

1.24µeV - 1.24feV

 

Take note that, as aforementioned, it was Sir William Herschel (1728 - 1832) who first discovered the existence of infrared radiation. As a budding astronomer who gained prominence upon discovering the planet Uranus, Herschel was looking into the nature of light.

Using the prism experiment made famous by Sir Isaac Newton years before him, Herschel found out that a region below the red spectrum of the colors of the rainbow (produced by the prism) not only was invisible but it also was hotter than most.

Note that infrared radiation is wide in terms of its spectrum. It is subdivided into the shortwave infrared or SWIR, mediumwave or MWIR, and longwave or LWIR. As such, specific sensor materials are used for each type. Here’s a table of the materials used by thermal imaging technology for each sector, its wavelengths, and practical applications.

Infrared Sector

Wavelength

Thermal Imaging Material

Practical Thermal Device Applications

SWIR

0.9 – 1.7 μm

 

InGaAs

(Indium Gallium Arsenide)

 

Circuit board, solar cell, counterfeit detection, food

MWIR

3.0 – 5.0 μm

 

InSb

(Indium Antimonide)

Optical gas imaging, detecting gas leaks, airport perimeter security, lab research, detecting toxic gases via drone

LWIR

8.0 – 14.0 μm

Mercury Cadmium Telluride

(MCT)

 

Strained Layer Superlattice

(SLS)

Most common, home inspection, temperature inspection, farm produce analysis

 

Know that most thermal cameras available commercially today are LWIR. There are two distinct technologies that satisfy the market: cooled and uncooled devices.

MWIR band of the ES is best served by cooled thermal imaging technology as the thermal contrast is above normal.

Most of the cooled infrared thermal cameras use Mercury Cadmium Telluride (MCT) or the Strained Layer Superlattice (SLS) in their detectors. Though these cooled devices provide superior high-level temperature precision, their prices are largely prohibitive for mass production.

The good news is microbolometer-based infrared cameras or uncooled devices, have risen to the challenge. While their general capacity in temperature precision detection is below grade that of cooled devices, technology is bridging the gap. Many of these devices available for the mass market approach the higher ability of cooled devices in precision.

How Much do Thermal Cameras Cost?

They can range from as little as a couple of hundred dollars to over several thousand dollars, depending on the applications and the features as well as the thermal resolution. The best way to get started is to have your needs assessed by a thermal-imaging professional. That way, you get to know your best options before you hit the buy button.

On the other end, getting products from trusted manufacturers is wise. For instance, PerfectPrime products come with an unheard-of 60 days guarantee. A perfect way to get the best thermal cameras without the hassle.


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