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Thermal and multi-sensor cameras in view

XtraVision believes that the thermal surveillance market is a growing market; there has been a definite uptake in sales of this technology, with more manufacturers developing products to compete in the market.

Even with the advent of long-range technologies such as radar, the thermal market will have its place as there will always be a need to visually verify alarm events to ensure a response is required as well as to understand the threat on the ground to respond appropriately

Thermal imaging cameras produce an image that portrays objects using their temperature instead of their visible properties. All objects warmer than absolute zero emit infrared radiation in the MWIR and LWIR wavelengths (3 µm–14 µm) in an amount proportional to the temperature of the object.

Thermal imaging focuses and detects this radiation, then translates the temperature variations into a greyscale image, using brighter and darker shades of grey to represent hotter and cooler temperatures, which gives a visual representation to the heat profile of the scene

The benefits of thermal cameras

• This technology provides enhanced detection in extreme weather conditions which affect visibility.

• It is perfect for use with video analytic products.

• It offers a larger viewable area, thermal cameras are designed to cover long distances.

• The costs associated with covering perimeter boundaries include:

◦ Fewer cameras required due to long range and enhanced coverage.

◦ Less poles required for same coverage.

◦ Less power and communication infrastructure requirements in terms of termination and transmission devices.

◦ Reduced installation costs.

• No additional lighting required, thermals can operate and produce an image in complete darkness.

• Boosts analytics performance:

◦ By eliminating false alarms caused by shadows, clouds or lighting.

◦ Works in bad weather, heavy rain, snow or darkness.

There are however a few considerations to be factored into the choice of product for your perimeter design.

• Thermal camera specification: image frequency of 9 Hz or 25 Hz.

• Detector type: There are an array of detectors available both in uncooled and cooled.

• High resolution thermal cameras often have a 640×480 detector, which delivers 307 200 pixels; compare that to 76 800 in a thermal imager with a 320×240 detector. Standard formats are 160×120 (19 600 pixels), 384×288 (110 592 pixels), 640×480 (307 200 pixels), and 1024×768 (786 432 pixels). The higher the resolution the better the image will be and the more information available for use with video analytic products.

• Thermal camera sensitivity is measured in milli-Kelvins (mK). Cameras are more sensitive with values at the low end of the scale. For example, cameras with 50 mK are about four-times as sensitive as a camera with 200 mK. The more sensitive (50 mK) cameras provide a wider temperature difference, resulting in more detail in the thermal display.

• There are an array of lenses available. The f-number (ƒ/#) or f-stop refers to the ratio of a lens’s focal length to its aperture’s diameter, and indicates the amount of light coming through the lens. Lenses are typically specified with their maximum aperture ability. For thermal infrared cameras, having a lower f-stop number increases the image contrast and clarity, which results in higher detection distances. This is particularly true for uncooled LWIR cameras where lower f-number lenses like ƒ/1.0 to ƒ/1.6 are required.

• Ideally, an ‘athermal’ or ‘athermalised’ lens would have no change to image quality over the full operating temperature range across the full FoV (field of view) of any detector with which it is used. In practice, there are many limitations to this ideal for which a lens user or purchaser should be aware.

Latest thermal camera developments

Most thermal camera perimeter security solutions are typically deployed on the edge of a perimeter and are limited to fixed and narrow fields of view. Built on a premise of doing more with less, Thermal Radar protects from the ‘inside out’ with a continuously rotating thermal sensors covering and area with a radius of up to 500 m.

Unlike an active radar system that emits radio frequency (RF) waves, Thermal Radar is a passive thermal intrusion detection system. It is available in five models depending upon the customer needs and detection distances required. Thermal Radar scans a 360-degree area and can detect human beings within a 1 km in optimal environmental conditions and with a clear line of sight.

The system snaps and analyses 480 thermal images per minute from up to 16 camera positions as the thermal sensor is rotated at 30 to 60 RPM. The images are aggregated, analysed and complied into an ONVIF-conformant RTSP video stream which can be easily used by a video management platform. The Thermal Radar RTSP stream displays the full 360-degree coverage area, while also showing a detection alarm window as well as an integrated geo-spatial map of the coverage area.

Multi-sensor PTZ systems

The Accuracii Mini HD is a compact and lightweight system, which combines two advanced video channels: a uncooled thermal camera and a full HD visible camera. Integrated on a continuous 360° pan, +/- 90° tilt positioner, it delivers 24/7 security. This miniature camera system is available in several lens configurations that offers complete scene awareness and threat detection from a person up to 3 km and a vehicle beyond 8 km.

The Sii OP thermal camera is one of our most sophisticated detection systems to date, with onboard VMD and a suite of cybersecurity features. This thermal imaging camera boasts easy installation, including thermal and visual capabilities and ONVIF conformity for seamless third-party integration.

This device allows you to cover more ground with fewer cameras, compared to traditional CCTV solutions.

Having both video signals available to stream to VMS of choice allows one to have the best in terms of video analytics detection combined with thermal imaging as well as having and additional IP HD video signal to verify alarm and additional details related to the alarm.

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