An Ultimate Guide To Thermal Cameras and Beyond

Thermal cameras are truly a work of wonder. First up, they’re not really cameras in the truest sense of the word. Note that the usual visible-light cameras, such as the ones you have on your smartphone, see the world as our eyes do: dependent on the presence of light. Thermal cameras, however, are more like sensors. They detect infrared radiation or what we normally call heat. 

And that makes these electronic devices so awesome. They see what our human eyes can’t. What’s more, these impressive devices can do all that even in total darkness. 

Welcome to the wonderful world of thermal cameras!

In today’s modern world where interplanetary travel is already being actively explored, you really can’t underestimate the importance of thermal cameras and their role in expanding man’s dominance in the universe. 

To boot, we wonder at how a thermal camera can detect our body temperatures from a safe distance without touching any of our skin. And become a standard tool in curbing the spread of COVID-19, a world-changing virus, in the process. 

But apart from being the go-to screening tool in most establishments today, thermal imaging technology is also deployed in the most powerful space exploration stations in the world. Thermography (the study of heat distribution in a region) via infrared imaging technology is used to determine the birth of stars, billions of miles away. 

All these tell us that knowing the ins and outs of a thermal camera works greatly to our advantage. Of course, this is assuming productivity and being effective is sitting on top of your list. Read on. 

 

Thermal Camera: The Camera that’s Not a Camera

At its most basic, a camera operates like our eyes. It’s an optical instrument meant to capture an image. So if after months on end of traveling on foot, you finally reach the top of Mt. Everest, you definitely would want to bring a camera. To tell the world of your conquest. 

History is replete with such a momentous event. Small wonder the first thing Commander Neil Armstrong (along with module pilot Neil Aldrin) did when landing on the moon was turn the camera on for everyone to see. It’s true. Their first steps as they climbed down the ladder to make man’s first-ever moonwalk were telecast live and seen around the world on the 21st of July, 1969

But surprise, surprise. A thermal camera does not actually capture images. Instead, it detects the presence of heat — and discerns varying degrees of it. It’s a complex electronic device that senses the infrared radiation emitted by a target object. Take note that every material on the planet, even ice, radiates infrared energy. 

To be able to detect heat, thermal cameras use thermal sensors, specifically designed to capture the presence of infrared radiation or heat. Bear in mind that in many instances, heat plays a central role in discerning the true state of material under study. Therefore, by knowing the distribution of heat in a target scene, thermal imaging cameras have become a standard tool in some of society’s key fronts. These includes:

  • Medicine
  • Industrial electronics manufacturing
  • Firefighting
  • Home Inspection
  • Astronomy

And there’s no tool quite like it. With thermal images generated, you get a detailed analysis of your material under observation in a jiffy. This is exactly why it took no less than the September 11, 2001 attacks - the deadliest terrorist threat to ever happen on American soil - for the country to see how crucial the role of thermal cameras is in a life-and-death situation. 

To begin to wrap our head on such a wonderful phenomenon, we must first trace the history of the device. 

 

Tracing the Origins of Thermal Cameras

It was the works of Sir William Herschel (1738 - 1822), a German astronomer who discovered the planet Uranus in 1781, that started the ball rolling. Working as the private astronomer to King George III of England, Herschel through the famous prism experiment measured the “heat of each of the colored rays” of the sun’s visible light using thermometers. 

He soon realized that there is an invisible region after the red color that is hotter than the rest. That’s how he discovered infrared radiation in 1800. 

But what is infrared radiation if you can’t measure it? It wasn’t until 1880 that the bolometer, an infrared radiation sensor, was invented giving man the ability to size up infrared. Seizing upon such a glorious opportunity, the military used the first thermal imaging devices after World War I. Specifically, these helped boost the anti-aircraft defenses of Great Britain in that war. 

U.S. military would soon jump in the fray. In 1947, they invented the first infrared line scanner allowing the thermal camera to develop corresponding images from infrared input. Pretty soon, American soldiers were touting a more advanced infrared imaging technology in the Korean War (1950 - 1953).

Slowly, practical use of the thermal camera sipped through the cracks. But it carried a heavy price. American firefighters, for one, started using the device in their engagements, allowing them to see through smoke and assess the situation better. However, as promising as these first-generation thermal cameras were, they were heavy and carried a less-than-friendly price tag. 

In 1980, the microbolometer was invented by Honeywell. It works like a standard bolometer but it was much lighter. In short, this invention would allow thermal cameras to be more compact and lighter than ever. The microbolometer technology was declassified by the American Government in 1992. 

By the late 20th century, thermal cameras started to be part of mass culture. For one, Hollywood depicted the technology in Arnold Schwarzenegger’s movie blockbuster “Predator” in 1987. As a new century dawned, thermal cameras became much more affordable. Such a dip in price was made possible with smart IR sensors inside modern infrared imaging cameras. 

It’s no surprise, widespread adoption followed. By 2008, thermal cameras were fast becoming a standard tool for every home inspector worth his name in salt. Not to be outdone, industrial and commercial applications followed. 

 

Thermal Camera Top Applications Today

All sorts of people are attracted to the realm of the invisible. So, it’s no surprise the thermal camera’s ability to uncover what the eyes can’t see has spurred a long list of uses that has only gotten longer over the years — from detecting ghosts to zeroing in on electronic defects in a PCB. Many of these uses are for hobbyists while a slew has become operational standards both for industrial and home use. 

Lest we forget, infrared detection technology is still largely being deployed by the military and police. Also, it must be noted that right after the 911 bombings, the use of handy thermal imaging technology has been widely adopted by firefighting units all over America buoyed by increasing government funding. Apart from that, thermal detection became a standard screening tool in the fight to contain the COVID-19 virus.

Other popular uses of the device are: 

  • Ghost hunting
  • Animal clinics
  • HVAC systems maintenance
  • Home inspection
  • Hobby photography
  • Maritime navigation
  • Environmental studies
  • Surveillance and security
  • Airport security
  • Law enforcement
  • Automotive night vision
  • Medical testing/diagnosis
  • Gas leak detection
  • Electrical wiring maintenance
  • Roof inspection
  • Building inspection
  • Mechanical/industrial equipment inspection
  • Night vision
  • Game hunting

Take into consideration that not all thermal cameras are created equal. Thus, it is incumbent upon you to do your due diligence to arrive at a fitting model that caters to your purpose. 

As thermal camera prices have dipped considerably over the years, it certainly is a ripe time for you to explore your precious abode with a handy infrared camera unit in hand. Not only will you be able to screen visitors for rising temperatures but also you’d be able to keep your house in order that way. 

And yes, it would be harder for junior to hide behind the curtains now.

To show you how thermal cameras have conquered the hearts of many Americans, here are some of the most common uses of the device up close. 

Self-driving Vehicles

Needless to say, driving is one of the most complicated human endeavors. Anyone who says otherwise should take a look at over 30,000 fatal vehicle accidents that happen yearly in America. Now, allowing a machine to effectively navigate the road ahead is definitely a tall order. Machine learning will have to factor in a huge amount of data of the external environment to be able to navigate the streets. 

It’s one tough challenge. Not only will an autonomous car have to contend with traffic along the way, but also visibility factors are going to affect its vision. We’re talking about smoke, fog, rain, darkness, and glare. Even a high sunbeam can be an aggravating factor as it can be blinding. 

Solution: 

Thermal cameras will have no problem seeing through these challenges. As it detects heat, it won’t have any issue detecting upcoming traffic or humans crossing even in total darkness or the presence of smoke, fog, and rain. Plus, they can extend the reach of your headlights farther than otherwise possible. This allows an autonomous car to see dangers far ahead, eluding them in the process. Little wonder top car manufacturers integrate these thermal sensors as part and parcel of a car’s safety mechanisms. 

Also, engineers developing ADAS (Advanced Driver Assitance System) are finding ways to incorporate thermal imaging technology into the equation. Already, we’ve seen how the technology has improved Automatic Emergency Braking or AEB to save lives. Factoring thermal cameras means safer roads ahead for self-driving cars no matter the weather. 

Firefighting

The incidence of fire is one of the most destructive forces on the planet. The September 11 terrorist attacks alone claimed the lives of nearly 3,000 Americans, over 300 firefighters including. And that’s not counting the long-term effects of the fumes and contaminants on the scene. Overall, Americans pay a huge price for all sorts of fires that erupt all over the country. California wildfires alone cost over $100 billion in 2017. 

When firefighters rush to a scene, they are confronted with chaos. Proper assessment of the situation is an uphill climb as smoke, debris and the raging fire itself can obstruct the human view. Relying on bare eyes to locate a survivor or trace the seat of the fire can be next to impossible. 

Solution: 

As thermal imaging technology can detect varying degrees of heat, it can alert rescuers of the presence of survivors. The human heat signature stands out like a sore thumb in the thermographic results. Additionally, it can help contain the fire faster as the device can identify the seat of the fire. 

Plus, leaking gas and overheating electrical pieces of equipment are apparent in the eyes of infrared technology. Dangers that normally are not visible to the human eye such as hot spots in walls can easily be detected using the device. Best of all, thermal technology allows firefighting units to assess the situation in a jiffy, helping them suppress the fire and resolve the situation faster with far lesser casualties. 

Skin Temperature Screening

With nearly 164 million infected and over 3 million dead worldwide, the COVID-19 virus is giving everyone on the planet the scare of their lives. The solution long employed decades before other virulent epidemics happened on the planet is limiting people’s movement. The ability to detect fever, a known symptom, has therefore become a vital resource. It can help determine possible infected persons, curbing the spread of the virus in the process. 

The problem is taking the temperature with traditional methods can put you at risk. Being able to capture skin temperature without direct contact is therefore key. 

Solution: 

Thermal imaging technology is the right tool at the right time. By determining a person’s temperature from a distance, the device is the perfect choice to screen people. Thus, buildings and establishments all over American have made it a point to install the technology to safeguard their entrances. 

Even better, a thermal camera comes with added features that make screening a lot more efficient. For one, you can’t beat the speed of thermal to detect skin temperature. Secondly, you can employ crowd detection for faster results. Just make sure you’re setting things right and deploying the right unit. For one,, you’ll have to remember a thermal camera isn’t actually a medical tool in the sense that it can’t detect the presence of disease or the virus for that matter. 

Home Inspection

Heat is a good indicator of a host of issues. When your air conditioning has issues, it can dissipate heat. When your electrical wiring short circuits, heat also materializes. Being able to detect the presence of heat is, therefore, paramount to contain issues that are closer to home. The problem is with so many things happening indoors, detecting such heat surges can take ages. 

Then there’s the case for insulation. A poorly insulated home means heating or cooling is largely ineffective. HVAC, in this sense, is running inefficiently as poor insulation allows heat/cooling to flow out of your precious abode when you need it kept inside. The end result? You’re paying an energy bill that actually reflects more energy than what you actually need. 

Solution:

Handy thermal cameras can detect packets of energy loss. Once it zeroes in on a sudden drop, locating these holes in a home’s insulation is easier. The same holds true for both heating and cooling systems. A hole in your insulation is bound to display an unmistakable heat signature as opposed to the temperature of your indoor surroundings. 

Additionally, a portable thermal camera can detect heat surges in an electrical system resulting from any electrical anomaly. Using an infrared camera is therefore the fastest way to uncover an anomalous electrical circuit be it in your home system or in your child’s class projects. 

 

How Does a Thermal Camera Operate?

Fig.1 The Electromagnetic Spectrum 

It’s simple actually. To understand how a thermal camera works, we must understand three things: 

  • The nature of heat energy
  • How thermal camera captures heat energy
  • How thermal camera displays captured heat energy

It’s easy to be fooled by the things we see. They are, after all, what appeals to the senses. But what we see is actually due to visible light, a small portion of the wider electromagnetic spectrum. 

For lack of a better demonstration, we can refer to the colors of the rainbow or ROYGBIV. These colors (e.g., R for red, O for orange, Y for yellow) are actually the various wave spectrums of visible light. Each spectrum representing a different wavelength and energy level. 

Sir William Herschel measured each of these colors and saw that heat increases from violet to red. What’s more, the German astronomer found out that there’s an invisible region after the red color that radiates even greater heat. That’s how infrared radiation (IR) or heat energy was discovered.

Remember that everything on the planet emits infrared radiation. An object with a temperature of absolute zero may not emit any heat energy. However, such an object is just theoretical as absolute zero entails all atoms in the material to be standing perfectly still, an impossible feat. Thus, as different objects on the planet radiate varying degrees of infrared radiation, they will register different levels of heat in the thermal camera. 

So the question now is how does the thermal camera capture heat energy?

And that is why the invention of the bolometer matters. Bolometers, in simple terms, detect infrared radiation. It absorbs radiation and in the process increases its temperature according to the amount of heat received. In short, it’s a thermal detector. 

Other thermal detectors most common today are thermocouples and thermopiles. The invention of the microbolometer made possible the manufacture of more portable compact thermal cameras.  

To note, the heat on the surface of an object is directly proportional to the temperature of that object. Since each object radiates heat energy or IR differently, each has a unique heat signature. 

Then how do you create a unique picture representing the heat patterns of a thermal image? 

To do that, the different changes of the temperature detected by the thermal sensor are converted into corresponding shades of grey. The resulting images represent hotter areas as lighter while cooler areas appear darker. The brighter the color therefore the hotter the object. 

How about the colors on the screen of the thermal device? 

Older infrared imaging devices displayed a greyscale

. Today, however, we have colored representation. The RGB coloring is thanks to a color filter array (CFA) and tons of algorithms designed to construct a colored version of a greyscale image. 

What’s Inside?

A thermal imaging camera is powerful. It’s capable of detecting temperature variations up to 1/20th of a thermometer degree. That’s a feat impossible for human eyes. 

Basically, there are three main parts of a thermal camera. These are: 

  • The lens
  • Thermal sensor
  • Processing electronics

What’s important is the lens must allow infrared radiation to pass through and be captured by the thermal sensor. That’s why materials used for the lens are glasses made of zinc, selenide, germanium, or Chalcogenide. Ordinary glass, the one used in visible light cameras, cannot be used as glass can effectively block infrared radiation. 

Once captured, thermal radiation coming from objects under observation will be processed by thermal sensors (e.g., microbolometers). Said sensors determine the specific resolution which usually is ranging from 80 x 60 pixels (low res) to 1280 x 1024 pixels (high res). 

But wait, isn’t that low resolution?

Yes, it’s true. You might be wondering why the resolutions are rather low compared to smartphone cameras which can don 100-megapixel resolution or high-res standard cameras which can go as high as 400 million pixel resolution. 

Bear in mind that thermal cameras measure infrared radiation which carries longer wavelengths compared to visible light. Thus, it’s important that sensor elements also are larger compared to ordinary visible-light cameras. 

Lastly, you have the back processor electronics which receives data from the thermal sensors. This is where said data is converted to color representations for display. 

 

Diving into Thermal Camera Image Quality

You could be wondering about how to get the best image quality for your thermal camera. Truth be told, it’s a legit ask. In the process, it’s highly likely you’re going to use a standard visible-light camera as a reference. When today’s cameras don 100 megapixels and beyond, why not, right? 

Right off the bat, know that a thermal camera (as mentioned above) is not a camera in the strictest sense of the word. It’s a sensor — specifically, an infrared radiation sensor attached to a digital image converter. It detects photons of heat, generates a commensurate electrical output then digitizes said output for everyone to see. 

That means obtaining the best picture quality is not the right measure for an infrared camera. Rather, it’s the ability to accurately detect heat energy that separates a so-so thermal camera product from a stellar one. 

With that in mind, you should know a better image quality is possible with a thermal camera. To that end, three things should come to mind. These determine how one product fares against another: 

  • Pixel resolution
  • Thermal sensitivity
  • Spectral Range

Pixel Resolution

The higher the resolution the better is the ability of a thermal camera to detect heat differences in a target scene. At the heart of an infrared camera is the TPA or thermal pixel array. This is the infrared sensor which is actually a rectangular array of pixels. Pich (in microns) is the distance between the center of one pixel to the next pixel’s center. 

The more pixel sensors you have the more powerful your device becomes. Consequently, the smaller your pixel pitch becomes the stronger your device detects.  

For instance, a 640 x 480 resolution thermal camera will be able to detect better than a 320 x 240 resolution. That’s because there are more sensors available for the former than the latter. 

Additionally, the bigger the resolution, the farther your thermal camera can detect heat. Thus, a 320 x 240 resolution thermal device can detect accurately from a distance of 60 feet, a job a 60 x 120 resolution thermal can do at a 30-feet distance. It’s best, therefore, that you get familiar with your job at hand before you choose a thermal camera that best fits your needs. 

Thermal Sensitivity

Thermal Sensitivity dubbed also as NETD (Noise Equivalent Temperature Difference) is basically a measure of the smallest temperature difference your thermal camera can detect. 

But here’s the trick. 

It’s not about getting high numbers. The lower the NETD the better your camera can detect minute temperature differences. In short, it’s more accurate. 

Measured in milliKelvins or mK, a NETD usually has a value ranging from 50mK to 250mK. One with 50mK is capable of detecting subtle applications, say moisture issues, better than a thermal camera with 250mK. 

Take note, however, that if you’re not planning to use your thermal in applications with subtle differences, a thermal device with low NETD will be useless. 

Spectral Range

Remember the electromagnetic spectrum? Infrared radiation has a range of wavelengths that is far too wide for one thermal camera to detect. Spectral range, therefore, is the range of wavelengths your thermal device can detect and measure. It is expressed in micrometer (µm)

Thermal cameras which cater to gas detection (butane, methane) are mid-wave cameras with a spectral range between 3µm to 5µm. However, most thermal cameras in the market today are longwave cameras with a spectral range of 8µm to 14µm. These cameras offer wide applications, from home inspections to firefighting. 

 

Introducing: Two Main Types of Thermal Camera 

Thermal cameras can be a lot of things for a lot of people. They can be a prized possession for home inspectors who must ensure a property is as energy-efficient as can be. But there are uses in thermography that require far more finesses. One used for R & D is atop that list.

As such, there are two main types of thermal cameras. In this regard, being able to match the right thermal camera to the job at hand is wise. 

Cooled Thermal Cameras

Right off the bat, these thermal cameras are bulky. But the weight they carry is matched by their superior heat detection abilities. Enclosed in a vacuum-sealed case, these devices are cooled via cryogenic cooling mechanisms. Take note that these cameras must be cooled or they can’t function without one. 

When you prioritize precision, cooled thermal cameras are the go-to device. For instance, you can detect a handprint on a wall placed there in seconds with a cooled thermal camera, a feat that would require the hand to remain in minutes on the wall before an uncooled thermal can detect the heat signature. 

On the other hand, cooled thermal cameras are much more expensive. Plus, you’ll take longer to produce results as the device needs to be cooled every now and then. Thus, this type of thermal camera is not as popular as uncooled ones. 

Uncooled Thermal Cameras

Uncooled thermal cameras are bolometer-based. As they do not need to be cooled, these devices are as portable as you want them to be. So over the years, they’re a heavy favorite for a slew of professions, thanks to their lightweight nature. So long as you don’t need utmost heat-reading precision. 

What makes them even more attractive is they can operate without downtime as they require a lot less maintenance compared to cooled alternatives. Add their lower price tag and it’s no accident they’re a household word in the market today. 

 

What’s the Price Range of Thermal Cameras Today?

Right about the close of the 20th century, fire departments were already seeing the massive advantage of thermal cameras, dubbed TICs (thermal imaging cameras) in fire personnel lingo. The technology’s ability to see through smoke is simply unequalled. 

But one thing hindered many fire departments all over America to deploy TICs in every engagement. And that is the price. With thermal cameras carrying a price tag of over $20,0000 each, purchasing it was like facing a wall

In retrospect, there is a checklist of points that should make TICs pricey. And we should understand that the materials alone in creating one are not your run-of-the-mill variety. 

To boot, you use a special kind of lens for thermal cameras. You can’t just use plexiglass, a common lens for standard visible-light cameras today, as it won’t be conducive to infrared radiation. More often than not, you use Germanium, a costly material.

Then, there’s the case for the sensors which also command a price. Add to all that, you have circuit boards and electronics that convert the electronic signals from the sensors into a readable output. 

Luckily, technologies emerged that pushed the price of thermal cameras downwards. We’re talking about the microbolometers IR detector found in the majority of thermal cameras today. 

As the microbolometer doesn’t need active cooling (discussed above), less pricey materials can be used to create TICs. Also, this allowed portable more compact designs. 

Today, you can avail yourself of WiFi-ready portable 206 x 156 resolution thermal cameras at $599 or even less. It’s really amazing how technology can help us make the most of such a wonderful product with added guarantees. 

Here’s a perfect example from PerfectPrime

Can You Turn Your Smartphone into a Thermal Camera?

Technically, it’s possible. All smartphones carry an image sensor that can detect infrared light. Unfortunately, this infrared light is filtered before it reaches the sensor so as to produce crisp-looking natural light pictures. 

The sensor plate consists of charge-coupled devices that are connected to the circular assembly which houses a small infrared filter. Said filter ensures no infrared radiation stands in the way of a great picture. 

If you remove the infrared light filter, your smartphone can work as a thermal imaging device. Here’s a Youtube video showing you how it’s done. 

Bear in mind, however, that the infrared image sensor in your smartphone is very limited in terms of the number of pixels. So if you want a professional-grade thermogram, you will have to look elsewhere. 

A better alternative for you is to rely on a thermal camera add-on for smartphones. A good example is PerfectPrime’s IR203 for iPhone devices. A powerful thermal camera, it can transform your iOS device into an 80 x 60 pixel infrared camera in a jiffy. Just simply connect the device to your cellphone and open an app and voila, you can now uncover various thermal heat signatures of things around you. 

What’s more, you can also do the same for Android devices. But instead of IR 203, use PerfectPrime’s IR202 instead. Note that not only is this thermal add-on lightweight, but also it’s super user-friendly allowing you to make the most of a thermal camera just about anywhere you go. 

 

Thermal Camera Quick FAQs

Which is Better, a Thermal Camera or a Night Vision? 

Indeed, this is a tricky question. That’s because each is a tool with has a specific purpose different from the other. You really can’t compare apples and mangoes, right? It’s like comparing a hand saw with a chain saw. Of course, chain saws are stronger but you don’t use a chain saw to cut down a small piece of wood. That job goes to a hand saw. 

First and foremost, therefore, before you decide on the best tool, you must ask yourself: What kind of work would you like to do?

Don’t be fooled by all the tech and the green light. Basically, night vision is a camera. It is dependent on the presence of light to function. So what it does it does is it receives bounced light from the surroundings to create a picture of that surrounding. It’s just like how our eyes operate. 

What makes night vision “see through the dark” is image intensification. Using what’s called image intensifiers (military term) or image enhancers, night vision goggles (NVGs) amplify what little amount of reflected light is there at a dimly lit scene to get a better picture of the environment. That’s how you get those greenish pictures you see in the movies. 

The problem with NVGs is you would still need ambient light to come up with a picture. In total darkness as in a tunnel, night vision technology would utterly fail. 

Thermal cameras, on the other hand, are not cameras. They are sensors, specifically heat sensors. So they don’t need ambient light to create an image. You get the heat signatures of what’s in front of you with thermal. Meaning, you’ll still know if a human or an animal lies ahead even in pitch darkness. 

Here’s a comparison of what thermal imaging and night vision camera can or cannot do: 


Thermal Camera vs. Night Vision Table Comparison

Category

Thermal Camera 

Night Vision

Comment

Low-light conditions

YES

YES

Both functions.

Total darkness

YES

NO

Thermal detects heat no matter the light conditions. 

See through fog/dusts/smoke

YES

NO

Smoke, fog, dusts easily obscures the night vision image.

See through leaves/foliage

YES

NO

Low contrast means subpar results for night vision.

Track residual heat (footprints, handprint)

YES

NO

Night vision operates like the eyes.

Detect from a distance

YES

NO

Image amplifiers at night vision operate within close distance.

Operate during the day

YES

NO

Night vision is worthless during the day as image enhancers could get compromised. 


Clearly, if you talk about seeing in the dark, a thermal camera would outmanoeuvre night vision technology. Thermal is your all-weather, all-terrain, round-the-clock heat detector that works without fail. 

Now, if you’re wondering why not use thermal camera technology for night vision? That’s a fair enough suggestion. And yes, it’s already happening. New generation technology night vision cameras are equipped with thermal imaging technology allowing them to see in complete darkness. Old-school NVGs are now slowly fading into the background. 

Additionally, there is also another NVG that uses infrared radiation. Unlike the modern NVG which are basically thermal in nature, infrared-led NVGs uses infrared light as active illumination. Meaning, it still acts like an old-school night vision. The difference is you get image amplification from infrared light. However, this is not as powerful as NVGs that use thermal cams to “see in the dark”. 

Here’s a table to show the differences of the night vision technologies over time: 

Night Vision Technology Through the Years

Night Vision Technology

Features

Comments

First Wave

Image intensification

Can operate in low-light conditions but not in total darkness

Second Wave


(active infrared-night vision)

Active illumination

Uses infrared as reflected light like a flash in a camera to convert a scene into an image

Third Wave

Infrared imaging technology

Thermal camera used as night vision. More powerful


So if you’d like to know which is the more powerful technology, then the answer is thermal cameras hands down. Exactly why night vision technology is incorporating thermal camera technology in its arsenal.

But if you’re out hunting at dawn and would want to know what kind of animal is in front of you, then night vision would be the answer. Like your ordinary camera, night vision has better target recognition compared to thermal cameras. In this sense, old-school tech wins. 

Again, asking the right question from the onset is key. The question is not about what tool is more powerful rather it’s a question of what tool best fits the job at hand. 

What’s the Difference Between Active Infrared and Thermal Camera?

Terminologies can be confusing. In a sense, it can be scary too. Reason enough why learning what’s it all about is key. The confusion between active infrared or active IR systems and thermal imaging cameras is one such example. 

To understand active IR systems we must first remember that infrared light is a portion of the electromagnetic spectrum. As such, it has a range of wavelengths just like visible light has its own wavelengths which are of varying sizes. Near-infrared is closer to visible light. It has a shorter wavelength compared to far-infrared which is closer to microwave radiation. 

Far-infrared waves are the ones we experience as heat. It’s thermal. When we feel the heat from sunlight or of fire, that’s far infrared. On the other hand, shorter infrared wavelengths do not display so much heat. You’ll consider them as not hot at all. A good example is the near-IR you find in the remote for your smart TV

Active IR systems use near-infrared. Instead of heat, these systems use infrared to illuminate the scene so a camera can create a picture. A second-generation active-IR night vision is one example of such technology. 

On the other hand, thermal imaging cameras use mid to far-infrared energy. They are not used to illuminate a scene rather they sense differences in heat. Far-infrared does not sense reflected light. It’s the reason why it’s not affected by the glare of the sun, upcoming headlights, haze or smoke, or dust. 

 

Can Thermal Camera See Through Walls?

No, definitely not. A thermal camera can detect the heat signature of an object, such as a wall. So But it cannot see through something solid. 

However, if the other side of the wall is on fire and that fire affects the wall, it’s highly likely the thermal camera will know the presence of the fire by reading the temperature of the wall. 

Take note that this also depends on how thick or thin the wall is. If a wall is made of paper (theoretically), and a grizzly bear is behind it, there’s a good chance the camera can detect the presence of the predator. 

 

Can You Block a Thermal Camera?

Of course, that’s exactly why the right glasses must be used as lenses for the thermal camera. If not, the infrared radiation won’t be able to go through and is effectively blocked. 

Also, glasses in the subject under study could block a thermal camera’s ability to read its heat signature. Glasses, more often than not, act as a reflector. However, there are glasses (e.g., car windshields)that allow some infrared radiation to pass through. 

 

What Pixel Resolution is Best for Me? 

Again, to know what’s best for you, you must first ascertain what exactly is the work you need to do. A thermal camera hobbyist won’t need as much resolution as an engineer in a manufacturing plant who wants to ensure the machinery is working fine and without a hitch. 

To date, we have the following thermal resolutions and pixel size available in the market these days: 


Thermal Camera Product

Pixel Size

Resolution

Low Resolution

160 x 120

19,600 pixels

Middle Resolution

320 x 240

76,800 pixels

High Resolution

640 x 480

307,200 pixels


Well, your jaws should drop if you’re going to compare these numbers to ordinary cameras or even a smartphone camera. A standard iPhone dons about 12 megapixels of camera power. Translated that’s 12 million pixels. But there are smartphones today with cameras that go as high as 100 megapixels. What’s more, there are top-of-the-line ordinary cameras with higher resolution. 

However, you’d fare well to take note that (as mentioned above) thermal cameras aren’t actually cameras; they’re sensors. So the resolution plays a more crucial role in infrared imaging devices than in digital photography. 

That’s because the thermal camera’s resolution affects not just the image quality but also most importantly its ability to accurately measure heat differences. A higher-resolution thermal camera, therefore, can detect temperature differences better. 

In short, the higher the resolution of a thermal camera the more accurate is its temperature measurements. An infrared camera with 320x240 resolution, for instance, can detect the heat of an area smaller than a tenth of a square inch from a 6-feet distance, a job where the 160x120 resolution will fail. The latter won’t be able to produce an image even if the target is twice that size. 

What’s more, a better-resolution thermal camera is capable of measuring heat from a greater distance compared to lower-resolution ones. To sum up, this is what it offers: 

  • Better temperature detection accuracy
  • Better detection from a distance
  • Better images

With that said, it’s important you match the job with the right thermal camera. 

 

Can Thermal Cameras Pose a Health Risk? 

The short answer is no. When it comes to harmful electromagnetic waves, a thermal camera poses no health risk to its users. Furthermore, take note that thermal imaging devices are used in a non-invasive way. To note, unlike X-ray body scanners which have been banned before in airport use for their possible health risks (cancer), thermal cameras have been recommended by no less than the FDA as a safe method for fever screening in light of the pandemic.  

Indeed, a thermal camera can boost one’s health. Not only can it help humans detect fever from a distance but also it can look into possible health anomalies. In animal health monitoring, for instance, thermal cameras can show stressed parts of the animal’s body. By determining the presence of abnormal heat, a veterinarian can pinpoint possible problem areas in the animal under study. 

Even better, thermal cameras can protect you. As a powerful surveillance device that works perfectly in daylight and at nighttime, these devices can ensure no unscrupulous individuals will disturb your precious abode even while you’re sleeping. Looking at all the things it can do for humans, a thermal camera is truly a treasure trove. 


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