Using MWIR Cameras for Long-Range Imaging Round-the-Clock

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Traditional monitoring and surveillance often produces restricted coverage, especially in poor weather conditions and at night. Mid-Wave Infrared (MWIR) cameras give an advanced solution for long-range imaging in all light conditions and weather by using thermal imaging.

Due to modern advances in technology, MWIR cameras are now largely available for applications from laboratory research to perimeter surveillance. Sierra-Olympic Technologies produce a variety of MWIR cameras and components including the new Ventus camera core, which provides unrivaled performance and compact size.

Terrorism, crime, cross-border dangers, and increased recognition of possible threats mean that surveillance, security and monitoring are more important today than ever before.

Closed-circuit television (CCTV) cameras are traditionally used for security imaging and perimeter surveillance. Unfortunately, CCTV cameras are limited in the hours of darkness because their applications rely on detecting visible light. Furthermore, CCTV cameras can typically only cover areas up to 30 m, whereas borders and perimeters are often extensive areas; meaning maintaining lights and cameras for substantial areas can be expensive and complicated.

Mid-Wave infrared (MWIR) thermal imaging cameras can cover a number of miles and work in total darkness, and so offer an advanced replacement for CCTV, giving round-the-clock surveillance. Additionally, thermal imaging cameras can visualize situations and objects that may not be visible to the human eye, for example obscured objects or gas leaks.

Thermal Infrared Cameras Can be used in Land, Sea and Air

Recent advances in technology have resulted in thermal imaging systems that are less expensive, more compact, and more reliable than their predecessors. For some time, thermal imaging cameras have been widely used in military applications, but until recently high costs have not permitted their further application.

Thermal imaging systems are now employed in land, marine and airborne monitoring in applications including:

  • Firefighting
  • Perimeter patrol
  • Police searches
  • Wildlife research
  • Mine detection
  • Fault detection
  • Leak detection
  • Search and rescue

How Does Thermal Infrared Imaging Work?

Passive thermal imaging cameras, which are also known as Forward-looking infrared (FLIR) cameras, identify infrared radiation directly from objects such as vehicles or people, with no external illumination needed. The electronic images that are generated correspond to thermal gradients in the observed scene.

The infrared light detected by passive thermal imaging cameras falls into two ranges:

  • MWIR (3 µm to 5 µm)
  • Long-Wave Infrared (LWIR, 8 µm to 12 µm)

MWIR and LWIR cameras both have their advantages and disadvantages and the demands of your specific application should determine which camera you choose.

MWIR for Research, Radiometry and Continuous Monitoring

MWIR cameras excel at long-range surveillance applications including:

  • Critical infrastructure protection
  • Airport perimeter security
  • Vessel traffic monitoring

It is essential that infrared radiation passes through the atmosphere to the detector to be identified by passive infrared cameras. The LWIR cameras range is often limited by refraction, scattering, and absorption of LWIR radiation by CO2 and water vapor in the atmosphere. As MWIR radiation travels through the atmosphere, it is less impacted by scattering and absorption than LWIR.

So as a result, MWIR cameras give the longest detection ranges, seeing about 2.5 times further than LWIR, which enables them to identify vehicles, humans and objects, many miles away.

Clearer images are achievable with MWIR as thermal contrast and are often greater in the MWIR band than the LWIR band. MWIR cameras provide superior contrast and sensitivity with low background noise, which results in high-quality images. Furthermore, the noise equivalent delta temperature for an MWIR camera with long-range optics is typically 30-50 % better than an LWIR, resulting in sharper images.

MWIR cameras work in all environments and weathers, including high humidity. Humidity affects LWIR cameras more by than MWIR cameras, which makes MWIR especially suited to coastal and marine application.

In addition, MWIR cameras are also generally lighter and smaller than LWIR cameras with similar optics, making them the clear choice for applications with weight or space limitations, like airborne operations.

For tracking targets with a wide temperature ranges or fast moving targets, MWIR cameras can adjust integration times to visualize and track the target more clearly than LWIR. MWIR cameras have superior flexibility and sensitivity, making them ideal for use both in the laboratory and in the field.

Sierra Olympic Technologies for Long-Range MWIR

Since 1995, Sierra-Olympic Technologies have been producing advanced infrared imaging technologies and components to original equipment manufacturer (OEMs), government, military, and commercial customers. Sierra-Olympic supply a range of MWIR camera cores for high-performance, long-range, continuous infrared imaging. Sierra-Olympic MWIR cameras are well suited to a wide range of applications from laboratory research to long-range surveillance.

Sierra-Olympics Ventus series (275, 690, 700, and 900) bring together the very latest in lens, detector, and cooler design to produce a wide range of camera cores with unrivaled sensitivity and unmatched performance.

Ventus cameras guarantee easy to interpret, high quality images, using a variety of continuous optical zoom lenses combined with electronic image stabilization, de-noise processing, local area processing functions, autofocus, and sharpening.

The Ventus camera core family offers price and configuration advantages found in no other MWIR camera engine.

References and Further Reading

  1. ‘Ventus OGI’
  2. ‘MWIR’
  3. ‘Airborne Detection of Land Mines Using Mid-Wave Infrared (MWIR) and Laser-illuminated-near Infrared Images with the RXD Hyperspectral Anomaly Detection Method’  Ayhan B, Kwan C, Li X, Trang A, Conference Paper: Fourth International Workshop on Pattern Recognition in Remote Sensing, 2006.
  4. ‘Marine Fauna Mitigation using Thermal Imaging’
  5. ‘Perimeter security market driven by threat of increased terrorism ‘
  6. ‘MWIR or LWIR thermal cameras for surveillance applications?’

This information has been sourced, reviewed and adapted from materials provided by Sierra-Olympic Technologies Inc.

For more information on this source, please visit Sierra-Olympic Technologies Inc.


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