Cell phones, particularly smartphones, have become indispensable in our daily lives, and we carry them with us at all times. In many houses, they’ve nearly replaced home phones, cameras, video recorders, and PCs!
Can phone camera detect temperature? What if we showed you yet another way your smartphone can help you around the house?
To increase the insulation and efficiency of your house heating and cooling, locate gas leaks, “see better at night” with no light, contactless temperature screening, screen for termites, find leaks, or diagnose medical conditions, you may turn your cell phone into a thermal imaging camera.
Can Phone Camera Detect Temperature
Understanding how the existing camera works is helpful in learning how to use your phone as a thermal camera.
Smartphone cameras capture images by capturing ambient light and showing them as distinct combinations of red, blue, and green at varied rates.
Infrared light is recognized by the image sensor in your cell phone’s camera. Infrared light may be detected by cellphone camera sensors, making previously unseen light visible. Unfortunately, most smartphone cameras filter infrared light before it reaches the sensor in order to take a better picture with visible light, so if you want infrared photographs, you’ll have to wait.
The camera can only save shadows and dark photos without enough light while using the filter.
With charge-coupled devices, smartphones include a series of small plastic lenses that can concentrate light on the screen (CCDs).
CCDs convert light photons into electrons, which are then transmitted to a sensor housed within an aperture.
The pixel count of a photograph is determined by the number of CCDs used.
Light passes through a succession of lenses on its way to you. It also goes through an infrared (IR) filter, which makes the object’s IR photons invisible.
A thermogram (thermal image)
Unlike typical photos taken with a camera, thermal images do not display the precise color of the scene.
Seeing blue on the screen, for example, does not imply that the scene is the same hue. The colors blue and red signify cold and hot thermal radiation, respectively.
An average smartphone can be modified to produce thermal images, which can be utilized in a range of industries such as military, navigation, firefighting, surveillance, electrical and HVAC inspections, hunting, and so on.
Here are a few options for turning your smartphone into a thermal camera.
1. Look for a compact thermal camera
The Thermal Camera is used to acquire thermal images from a scene. It is very compatible and convenient.
This fantastic iPhone thermal camera features a lightning connector.
Don’t be alarmed! What is the purpose of a lightning connector?
It’s a basic connector that lets you connect your iPhone to other devices.
Other than Apple, this thermal camera is not compatible with any other smartphone manufacturer.
The Seek thermal camera has four different modes of operation.
It has a classic mode in which it works like a standard camera.
It has a temperature mode that determines the temperature in a specific spot on the scene.
Threshold mode, in which the temperature range that allows the camera to pick up a thermal image is pre-determined,
When connected to the right app, this multifunctional device transforms your smartphone into a thermal camera.
Because it is powered by your smartphone, there is no need to charge it separately.
Furthermore, the Seek thermal camera only captures the scene in thermal images. To diagnose faults, the user must compare the real image with the thermal version.
2. FLIR (Forward-looking Infrared)
FLIR is a well-known manufacturer of thermal imaging devices that can be used in a variety of scientific fields.
FLIR One is a standalone portable module that captures the scene’s thermal signature and allows the image to be stored on the smartphone.
It is easily attached to a mobile phone and is available in two different versions for Android and Apple.
FLIR One collects the scene’s thermal image as well as the visible spectrum’s dark edges and overlays them on top of the thermal image, integrating the two images.
This allows the user to see the image clearly, eliminating the need to compare the thermal image to the real scene manually to determine the exact desired location.
The FLIR One’s resolution, on the other hand, is lower than that of the Seek thermal camera.
In addition, the FLIR One thermal camera is a stand-alone gadget that must be charged independently.
3. Thermodynamic App
Another thermal camera for Android handsets is the Thermal App, which is commonly clipped to the edges of the phone.
It is connected to a smartphone by a connection cord and operates on the device’s power.
It has a standard lens mount that can accommodate 3 mm, 7 mm, 15 mm, and 35 mm lenses.
The temperature detection range is 41 to 194 degrees Celsius, which is quite limited when compared to the thermal cameras described above.
4. C60 CAT
The Caterpillar C60 is a smartphone produced by the Caterpillar business, which is a huge equipment manufacturer.
As a powerful business, it has developed a new smartphone with a rugged appearance that is ideal for military people.
This smartphone’s main characteristics are that it is waterproof and can endure pressure up to 5 meters.
The lockdown button can be used to utilize a shutter to close the front speaker and microphone.
Furthermore, the CAT C60 is the world’s first smartphone to use infrared imaging technology.
This smartphone’s thermal images are stacked and normalized, resulting in a thermal image that is mixed with a regular photograph.
5. Renovate Your Old Mobile Home
Lenses and a sensor plate made up of charge-coupled devices attached to a circular lens assembly are included in every smartphone.
A tiny Infrared filter is included in this setup.
The IR radiation from the scene is ignored by this filter. This is why when we take a normal photograph, we don’t detect any radiation.
However, if the IR filter is properly removed without causing damage to other components, the smartphone can be used as a thermal imaging camera.
To prevent making pricey mistakes, conduct your experiment on an old, disused phone.
Is it Possible to Detect a Fever with an Infrared Camera?
ONE OF THE COOLEST THINGS ABOUT INFLARED CAMERA is that you can point them at a scene and see how hot or cold it is. So, what if those creatures are people? Could an infrared camera, for example, be used to screen passengers at an airport for probable Covid-19 fevers?
On the bright side, there would be no need for physical contact, and the reading would be practically instantaneous. In fact, you may have seen photographs of handheld infrared devices known as temperature guns (which work slightly differently) being utilized in China in this manner. In industries, IR sensors are used to monitor the temperature of equipment without having to shut it down.
However, there are certain drawbacks to employing this technology to detect sickness in people. In order to do it correctly, you must first grasp how infrared sensors function. So I’ll go through everything with you. Aside from that, the mechanics are fascinating. I love these cameras because they allow you to see the world in a new light—literally.
Even if you can’t see it, everything emits heat
You don’t always obtain what you want with science. However, if you give it a shot every now and again, you might just receive something even better. In 1800, this is exactly what occurred to William Herschel. Herschel used a prism to separate sunlight into its component hues while testing light filters. Then he put several thermometers in place. He was aware that light warming an object, but he wanted to investigate the effects of each color separately.
Then he observed something strange: a thermometer at the end of the room warmed up as well, despite the fact that it wasn’t even in the light. What the hell is going on here? The reason for this was that light was shining on the thermometer, but it was invisible to human sight. That was the discovery of infrared light, as we know it today.
But hold on! There’s more to come. The wavelength of light emitted by an object can really be used to calculate its temperature. When you use an electric oven, you’ve probably seen this. The element glows a reddish-orange color when it gets really hot, about 2,000 degrees Fahrenheit (that’s the temperature of the element, not the air in the oven that bakes your muffins):
You wouldn’t touch something that was glowing like that, right? However, this isn’t a failsafe system. It may appear black when you first switch on the oven, say after a minute or so—no visible light is sent off—but it’s already hot enough to burn you. So, what if I use an infrared camera to take a picture? In the infrared spectrum, it looks like this:
You can see the light now. This is, of course, a false-color photograph. Because our eyes are unable to detect infrared light, the camera essentially translates, utilizing visible colors to represent distinct infrared wavelengths. Yellow is hotter than orange, which is hotter than purple in this palette (which you can adjust). (The orange object is a reflection from the top of the oven.)
Temperature Determination using an Infrared Camera
All objects emit electromagnetic radiation, which includes light, in a variety of wavelengths. You obtain a curve like this if you plot the strength of the radiation (technically the spectral power density) vs. wavelength for a given object.
In this statement, T is the temperature and is the wavelength of the light with the highest intensity (b is just a constant). This means I can determine an object’s temperature just by observing the hue of light it emits.
Because the vast majority of light is invisible, an infrared camera is required. It functions similarly to a standard digital camera, but instead of detecting visible wavelengths, it can detect infrared wavelengths. My infrared camera can even provide a temperature reading on the screen. These items are very incredible.
There is no reflection on you
But there’s a catch: Wien’s law only applies to radiation emitted by a “blackbody.” What exactly is it? A blackbody is an object that does not reflect light from the outside and produces all of its own illumination. A good example is an incandescent light bulb, which shines when the filament gets extremely hot. (This is why incandescent light bulbs are so inefficient.) They waste a lot of energy that you can’t see in the infrared spectrum.)
In actuality, most light is a combination of emission and reflection. So, if we want to use that light to determine an object’s temperature, we’ll need to know the ratio. This is captured by an indicator known as emissivity. It goes from 0.0 to 1.0, with 0.0 representing a fully reflecting surface and 1.0 representing a perfect blackbody. There are tables where the emissivity of various materials can be looked up.
Let me give you an example. Let’s say I fill two plastic cups halfway with ice water and set them both at 32 degrees F. I used aluminum foil on the outside of the cups, but I painted the foil black on one of them. Here’s how they appear when they’re parked in my driveway:
Let’s have a look at their apparent temperatures in the infrared region now.
Not only do they appear to be different, but the temperature readouts are also different—something that shouldn’t be the case. As you can see, the camera claims that the black cup on the left is 48.6 degrees Fahrenheit, whereas the silver cup is 86.1 degrees Fahrenheit. Because the aluminum foil surface has a lower emissivity (e = 0.04), this is the case. The majority of the infrared light seen by the camera on that cup is just reflected off the hot pavement.
What about human skin, though? Humans, on the other hand, are quite darker. The emissivity of a typical human is between 0.95 and 0.98. As a result, we’re not extremely reflective in the infrared spectrum. That’s excellent.
This is my hand. That’s virtually entirely me emitting light, thanks to my strong emissivity.
Body Temperature Measurement
Let’s get back to the question now that you know how it works. Is it possible to tell if someone has a high body temperature with an infrared camera? There is, however, an issue. The camera focuses on the outside of objects. A human’s core temperature should be around 37 degrees Celsius (98.6 degrees Fahrenheit), while the exterior skin is usually cooler.
In case you couldn’t tell, this is a picture of me. I experimented with temperature readings on various parts of my face, and the highest temperature I could locate was 95.3 degrees Fahrenheit in the inner corner of my eye. (An IR gadget maker, it turns out, recommends focusing on the tear duct.)
I took my internal temperature with a thermometer in my mouth and found it to be 97 degrees Fahrenheit. So, the question is if there is a consistent relationship between internal and external temperatures, allowing you to tell if someone has a fever.
Another factor to consider was that I needed to get the camera fairly near to the subject. It was around 10 cm away from my face in this situation. That would clearly be in violation of the 2-meter guideline of social distance. With a higher-resolution camera, you could probably correct that. I’m only using one that links to my phone at the moment (which is pretty cool if you think about it).
I also shot an IR photo of an open mouth for fun. It’s not my mouth, but a volunteer’s in this case (one of my sons).
This appears to provide a more accurate measurement (97.2), but I doubt you could persuade individuals to approach a camera and open their mouths. It’s difficult enough to encourage folks to stay at home.
Please take off your glasses.
Another minor issue: someone wearing glasses would have to remove them in order to assess the temperature of a tear duct. Why? Because, while glass is transparent to visible light, it is opaque to infrared light. Take a look at this photo of my dog staring out the window.
In the glass, you can see his reflection. The window functions as a mirror for infrared light. Take a peek at a human wearing glasses. In this situation, I’ll be the human.
Infrared lights with Rhett in sunglasses
Those aren’t sunglasses, but rather my regular spectacles. Because the infrared light from my eyes is reflected back onto me and does not pass through, they appear dark. The glasses also reflect infrared light from the room, which is colder than my body, on the exterior.
So, Does It Have a Chance?
Human bodies have a high emissivity, which is encouraging, and a decent infrared camera can detect slight temperature variations. The only serious flaw is that it only measures the skin’s surface temperature. However, if you’re just comparing folks and looking for outliers who are warmer than the others, this might be fine.
So, yes, I believe you could use an infrared camera to look for people with high body temperatures. Of course, this does not rule out the possibility that they have Covid-19. Perhaps they are suffering from the common flu. Perhaps they’re sweating from rushing to catch a flight. People can also be infected but show no symptoms. False positives and false negatives can occur in a variety of ways.
Is this to say it’s pointless? It’s not a diagnostic test; it’s just a screen. It’s not ideal, but it might be a rapid, low-cost, non-invasive way of scanning huge groups of people and, at the very least, identifying those who are more likely to be infected for further investigation.
Can phone camera detect temperature? An oral thermometer is, without a doubt, more accurate. Can you picture stopping everyone outside a grocery shop to put a thermometer in their mouth and wait for a reading? That would not be tolerated by the general public.