How Does a Thermal Camera Measure Temperature?

Thermal cameras have been used by homeowners, medical or health organizations, public institutions, and industrial companies for decades. This cost-effective and non-invasive technology emerged in its popularity for home and workplace safety.

This camera can detect any kind of leak, heat, moisture, insulation, electrical issues, pest infestation, and radiation. Without contacting the object, this camera can detect an accurate temperature. We will show you how does a thermal camera measure temperature in this article. So, stay with us.

Types of Thermal Cameras

You can use different types of thermal cameras for specific needs. Most popular thermal cameras for detecting temperature are-

Thermal Imaging Camera

Thermal cameras are best for identifying overheating machinery, visualizing entities, and evaluating electrical damages. The great part is, you can use the best thermal imaging camera for body temperature also. These cameras can find out the slightest temperature changes like, 0.1° and capture it.

The image is displayed with some false color, and each color represents a certain temperature. You can easily analyze the minimum and maximum temperature from the thermal camera image. This delicate technology can prevent the risk of illness and contagion.

This artificial intelligence can detect different people’s body temperatures. You can control this device through a computer or mobile. Considering the density of humans, these cameras are divided into three categories. These are-

High Traffic Density: This camera is best for large places with huge people. It analyzes people into four by four and generates the alarm when detecting high temperature.

Medium Traffic Density: It has an automatic temperature detection system. This camera is portable and requires a manual operation for measuring fever.

Low Traffic Density: This camera is ideal for those places where the amount of people is low. This cost-effective camera can detect fever automatically. You can use it in both stationary and portable ways.

Temperature Measurement Totem

This camera does not require any configuration action or installation process. You just have to place the device anywhere in a room. After that, plug it in, and it will be perfectly ready for use. People can measure their temperature by standing two meters away from it. It can show results with an error of +/-0.5°C.

How Does a Thermal Camera Measure Temperature?

Based on heat signatures, a thermal camera can provide an accurate temperature record. In this section, we will let you know How does a thermal camera measure temperature?

It uses an infrared spectrum range to capture the object’s thermal emission. Thus, it can detect the sources of heat and measure the temperature. For facial detection, this thermal camera uses artificial intelligence. It has an alarm system that warns about those people who have high temperatures.

This camera translates thermal radiation into visual images and indicates heat levels with different colors. For example, it will show dark red for high temperature and blue color for cooler temperature. Identifying the temperature by seeing the images is fairly simple for anyone.

As it can measure the temperature without contacting the object, so using this device is safe. It doesn’t require any unnecessary contact with infected individuals. You just have to hold the camera still and point it toward the target for a couple of seconds. At that time, this camera will create a visual result.

A thermal camera with high quality can measure a wide range of temperatures. Such as, it can measure from -40° to 550° Celsius and translates it up to 1022 F. This innovative technology is a perfect option for detecting the slightest changes in temperature. The sensors of thermal cameras can display the exact hot spot of individuals.

The person who handles the camera does not require to get closer to evaluate the person. It can measure body temperature faster than the other thermometer. For accuracy, this device is recommended the most.

Thermal Cameras

Features of Thermal Cameras

For accurate measurement, you should consider some factors. When choosing a thermal camera, consider the below technical features.


Some cameras consist of multiple ranges for measuring the wider span of temperatures more accurately. Selecting a thermal camera with a higher range is necessary for measuring highly tempted equipment.


A thermal camera is designed with a mechanical housing, lens, processing electronics, and thermal sensor. The camera lens is used to focus the infrared energy into the sensor. The sensor comes with several pixel configurations. The resolution of the camera is 80 × 60 to 1280 × 1024 pixels or more. The quality of the measurement depends on the camera resolution.


Another thing is NETD, which stands for Noise Equivalent Temperature Difference. It helps to measure the mili-kelvin. Also, make the camera able to pinpoint the smallest changes in thermal radiation.


You should consider the field of view for accurate measurement. It refers to the angle at which the camera is recording. The target must fit in the camera’s field of view. You need a wide-angle FOV lens with 45° or higher for close-up distance. On the other side, a telephoto lens with 12° or 6° will be better for long-distance.

Spectral Range

The last thing is the spectral response. It refers to the sensitivity of the camera sensor for various levels of radiation or wave lights. Most midwave cameras have a spectral range of 3µm to 5µm. Thermal cameras come with a longwave and consist of a spectral range of 8µm to 14µm.

First, consider the reason for what purpose you need this camera. After that, take these important specifications into account while comparing the thermal camera.


Thermal cameras are originally developed for military operations and surveillance. But right now, these cameras are used for firefighting, scientific research, industrial inspection, autonomous vehicles, and automatic braking. It is also very popular for building inspection such as moisture, roofing, insulation, etc.

Because of the accuracy of measurement, these cameras are now widely used for skin temperature screening. Many people feel confused about How does a thermal camera measure temperature? This article can clear their confusion.