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Advantages of MWIR in long-range imaging

December 19, 2018

Traditional surveillance and monitoring solutions often provide limited coverage, especially at night and in poor weather conditions. Mid-Wave Infrared (MWIR) cameras use thermal imaging to provide an advanced solution for long-range imaging in all weather and light conditions.

Recent technological advances mean that MWIR cameras are now widely accessible for applications from perimeter surveillance to laboratory research. Sierra-Olympic Technologies supply a range of MWIR cameras and components including their new Ventus camera core, which offers compact size and unrivaled performance.

Crime, terrorism, cross-border dangers, and increased awareness of potential threats mean that security, monitoring, and surveillance are more important today than ever before. Traditionally, closed-circuit television (CCTV) cameras have been used for perimeter surveillance and security imaging. However, CCTV cameras rely on detecting visible light, so their applications are limited in the hours of darkness. What’s more, perimeters and borders are often extensive areas and CCTV cameras can typically only cover areas up to 30m; which means maintaining cameras and lights for large areas can be complicated and expensive.

Mid-Wave infrared (MWIR) thermal imaging cameras, which can operate in complete darkness and can cover many miles, and offer an advanced alternative to CCTV for round-the-clock surveillance. Furthermore, thermal imaging cameras can visualize objects and situations that may not be visible to the human eye, such as gas leaks and covered or obscured objects.

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

Thermal imaging cameras have been widely used in military applications for some time, but until recently high costs have prohibited their further application. However, recent technological advances have resulted in thermal imaging systems that are less expensive, more compact, and more reliable than their predecessors.

Thermal imaging systems are now utilized in land, marine and airborne monitoring in applications including perimeter patrol, search and rescue, police searches, wildlife research, fault detection, leak detection, mine detection, and firefighting.

How Does Thermal Infrared Imaging Work?

Passive thermal imaging cameras, also known as Forward-looking infrared (FLIR) cameras, detect infrared radiation directly from objects such as people or vehicles, with no external illumination required.

The electronic images produced correspond to thermal gradients in the observed scene. The infrared light detected by passive thermal imaging cameras falls into two ranges: Long-Wave Infrared (LWIR, 8µm to 12µm) and MWIR (3µm to 5µm).  LWIR and MWIR cameras each have their advantages and disadvantages and which camera you should choose depends on the demands of your specific application.

MWIR for Continuous Monitoring, Radiometry and Research

MWIR cameras excel at long-range surveillance applications including airport perimeter security, vessel traffic monitoring, and critical infrastructure protection. To be detected by passive infrared cameras, infrared radiation must travel through the atmosphere to the detector. The range of LWIR cameras is often limited by absorption, scattering, and refraction of LWIR radiation by water vapor and CO2 in the atmosphere. As MWIR radiation travels through the atmosphere, it is less affected by absorption and scattering than LWIR.

As a result, MWIR cameras provide the longest detection ranges, seeing about 2.5 times further than LWIR, enabling them to detect humans, vehicles, and objects many miles away.

MWIR cameras can operate in all weather conditions and environments, including high humidity. LWIR cameras are more affected by humidity than MWIR cameras, making MWIR particularly suited to marine and coastal environments. Furthermore, MWIR cameras are also typically smaller and lighter than LWIR cameras with similar optics, making them the obvious choice in applications with space or weight limitations, such as airborne operations.

MWIR cameras provide superior sensitivity and contrast with low sensor noise, resulting in high-quality images. Clearer images are possible with MWIR as thermal contrast if often greater in the MWIR band than the LWIR band. 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.

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

Sierra Olympic Technologies for Long-Range MWIR

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

The new Ventus series (275, 700, 690, and 900) from Sierra-Olympic bring together the very latest in detector, cooler and lens design to provide a wide range of camera cores with unmatched sensitivity and unrivaled performance. Ventus cameras guarantee high quality, easy to interpret images using a variety of continuous optical zoom lenses combined with local area processing functions, electronic image stabilization, de-noise processing, sharpening, and autofocus.    The Ventus camera core family offers price and configuration advantages found in now other MWIR camera engine

References and Further Reading

  1. ‘Ventus OGI’
  1. ‘MWIR’
  1. 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.
  2. ‘Marine Fauna Mitigation using Thermal Imaging’
  3. ‘Perimeter security market driven by threat of increased terrorism’
  4. MWIR or LWIR thermal cameras for surveillance applications?


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