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How Do Infrared Security Cameras Work?

February 21, 2024

Mammoth Takeaways:

  • Infrared cameras use specialized sensors to detect infrared radiation, a form of light that the human eye cannot perceive.
  • Infrared cameras are equipped with LEDs that emit “invisible” infrared light onto objects in their fields of view. When the emitted infrared bounces off objects and returns to the camera, electrical signals are produced and processed into the visible range of the electromagnetic spectrum—allowing us to see objects in the dark.
  • The electromagnetic spectrum refers to the full range of all types of electromagnetic radiation waves, including visible light, infrared light, Bluetooth signals, Wi-Fi signals, X-rays, and more.

Infrared cameras enable monitoring and evidence collection in environments with poor lighting or no lighting at all. These cameras use LEDs (light-emitting diodes) to beam infrared light (also known as infrared radiation) onto surfaces in pitch-dark areas.

While an infrared-lighted area will continue to appear pitch-dark to the naked eye, specialized infrared camera sensors perceive the infrared as it’s reflected off surfaces. This reflected infrared provides all the information necessary for infrared night vision cameras to visualize objects accurately in dark settings.

But what exactly is infrared? And why can cameras perceive it while the human eye cannot?

While we’re at it, what’s up with the electromagnetic spectrum? Why do visible colors, infrared waves, radio station signals, and supernova gamma rays all find themselves categorized together?

We’re going to answer those questions (and others!) today.

Keep on reading for expert insights about infrared security cameras, the scientific principles behind them, and their business and organizational applications.

With nearly $500 billion in damages caused by property crime annually in the U.S., advanced security systems are leveraging infrared night vision technology to enable continuous visual monitoring regardless of lighting conditions.

Night vision dome camera with lens surrounded by infrared lights

How Infrared Security Cameras Work

Infrared cameras leverage LEDs (light-emitting diodes) and infrared image sensors to make surfaces visible in pitch-black environments.

This is how it works:

Beaming Infrared

First, a camera’s LEDs beam infrared light (that the human eye cannot perceive) onto a low-light or dark field of view.

Sensing Infrared

Second, the camera’s built-in infrared sensors (typically consisting of photodiodes or charge-coupled devices) perceive the infrared as it bounces off otherwise dark (non-visible) surfaces.

Semiconductor material within the sensors absorbs the light and generates electrons when the reflected light strikes infrared sensors.

These new electrons create an electrical signal proportional to the intensity of the reflected infrared.

Processing Infrared

In the third and final step, the camera’s processor maps the electrical signal intensities to corresponding grayscale values in the visible range.

In this way, objects in a scene that appear pitch-black to the human eye are made visible through infrared technology.

Benefits of Infrared Security Cameras

Enhanced Night Vision: By capturing and processing infrared light, these commercial security cameras produce clear images in low-light and no-light settings.

Discretion: Since infrared light is invisible to the human eye, these cameras can monitor dark areas without drawing attention.

For example, you can turn off the office lights at the end of a workday, and your infrared cameras will continue collecting high-quality footage without needing to blink.

Wide Application: From parking garages and office towers to school campuses and warehouses, infrared camera technology is leveraged for high-quality surveillance at any time and under any lighting conditions.

Understanding the Electromagnetic Spectrum

The electromagnetic spectrum represents all possible electromagnetic frequencies and wavelengths.

electromagnetic spectrum and common use cases

What are electromagnetic frequencies and wavelengths?

A frequency is the number of cycles an electromagnetic wave completes per second. A wave’s frequency indicates how fast it oscillates (or vibrates) and is measured in Hertz (Hz).

A wavelength is the distance between successive peaks (or other identical points) of an oscillating wave.

Together, wavelength and frequency describe the characteristics of electromagnetic waves and define their position on the electromagnetic spectrum.

What is electromagnetic radiation?

Electromagnetic radiation consists of vibrating, wavelike electromagnetic fields that carry energy as they travel through space.

Each type of wave, or electromagnetic field, has different properties, energy levels, and applications.

What they all have in common is that they’re forms of electromagnetic radiation—oscillating waves that carry energy.

7 Types of Electromagnetic Radiation

The seven types of radiation in the electromagnetic spectrum are defined by wavelength and frequency.

  • Radio Waves: These have the lowest frequencies and longest wavelengths in the electromagnetic spectrum. They’re used for communication, including AM and FM radio, television broadcasting, and wireless communication.
  • Microwaves: Have shorter wavelengths and higher frequencies than radio waves. They’re commonly used in microwave ovens and for satellite communication and radar technology.
  • Infrared Radiation: Infrared radiation, or infrared light, has wavelengths longer than visible light but shorter than microwaves. Infrared is often leveraged for night vision surveillance and is often central to how motion sensors work.
  • Visible Light: This is the part of the electromagnetic spectrum that we can perceive with our human eyes. It includes the colors of the rainbow, from violet (which has the shortest wavelength) to red (which has the longest).
  • Ultraviolet (UV) Radiation: UV radiation has shorter wavelengths and higher frequencies than visible light. It can be harmful to living organisms and is responsible for sunburn and skin damage.
  • X-rays: These have even shorter wavelengths and higher frequencies than UV radiation. They can penetrate materials and are most commonly used in medical imaging, such as X-ray radiography and CT (computed tomography) scans.
  • Gamma Rays: These rays have the shortest wavelengths and highest frequencies in the electromagnetic spectrum. These highly energetic waves are produced by nuclear reactions, neutron stars, pulsars, supermassive black holes, and supernova explosions.

Choosing the Right Infrared Security Camera

When selecting an infrared security camera, consider the following factors:

Range: Determine the distance the camera can cover with its infrared LEDs. Night vision range varies significantly between camera models.

Generally, consumer-grade infrared cameras have a night vision range of 30 to 100 feet, but commercial-grade models can see much further. Under ideal conditions, they can extend their range to 300 feet or more.

Resolution: Higher camera resolutions produce clearer images and are crucial for identifying details like faces and license plates.

Camera Type: The primary camera types (multi-sensor cameras, dome cameras, turret cameras, PTZs, etc.) are all available in infrared models. Each type offers unique advantages and drawbacks, so make sure any infrared cameras you choose are the right camera type for your particular monitoring and installation requirements.

Integration: Integrate infrared cameras with other security technologies, such as motion sensors and access control systems, to turbocharge the effectiveness of previously isolated systems. With integration, the whole is greater than the sum of its parts.

Infrared Night Vision

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Our team at Mammoth Security knows infrared camera technology inside and out. We’re also experts at furnishing and installing cutting-edge systems for access control, fire detection, intruder detection, and telecom data transmission.

For a 100% FREE site survey and consultation with a friendly and knowledgeable member of the Mammoth Security team, just click to contact us and fill out the form.

We’d like to set you up with a security expert who’ll walk through your site with you, answer your questions, identify your security vulnerabilities, and help you begin developing a security system that’s tailor-made for your property.




Infrared security cameras use LEDs to emit infrared light onto a scene, which is then detected by the camera's sensors. The sensors convert this light into an electrical signal, which is processed into visible grayscale images, allowing for clear vision in low or no-light conditions.

Infrared cameras provide enhanced night vision by capturing infrared light, producing clear images in low-light and no-light settings.

When buying an infrared security camera, consider its night vision range, image resolution for detail capture, camera type for specific footage, and placement requirements.

Infrared light is used in security cameras because it allows the cameras to "see" in the dark by illuminating areas outside the visible spectrum, making it perfect for night vision surveillance without being detected by the human eye.



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