Panoramic camera from HGH Infrared Systems uses rotary high-speed scanning

The Vigiscan panoramic camera uses rotary high-speed scanning to create a 360° image with up to 12 Mpixels.

Feb 11th, 2011

The Vigiscan panoramic camera uses rotary high-speed scanning to create a 360° image with up to 12 Mpixels. The sensor rotates once per second for real-time monitoring. A cooled detector has thermal sensitivity of 0.03°C. The rotary head of the sensor can be tilted ±20° to change the line of sight.
HGH Infrared Systems
Igny, France

hgh@hgh.fr

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Vigiscan infrared panoramic camera

The ultimate solution for long range surveillance

Introduction
Throughout the world, security issues are becoming increasingly important due to the current political and economical situation. Formerly reserved to the Defence sector, surveillance technologies for site monitoring are now required in many sectors. To this aim, very often a multitude of sensors using different technologies are installed, i.e. radar, light intensification cameras, CCTV, infrared barriers, lasers, IR cameras. These are spread around or within the monitored area in order to secure it.

Thermal imaging
Infrared thermal imaging is the most favoured technologies because it has already proven its effectiveness in all defence applications. It is passive, i.e. it cannot be detected by the intruder and it gives best image quality whether at daytime or night, seldom affected by weather conditions.

However, whilst monitoring an area of a few dozen metre radius is quite simple to implement, it can be particularly difficult and very costly for larger areas of several kilometre radius due to the number of sensors required. Also, beside the downside of its huge infrastructure costs involved, the set-up generates a large amount of information concurrently received on several monitors, thus reducing the surveillance effectiveness.

Technology selection
For reduction of the number of sensors, 360° panoramic vision is the most radical and effective solution. There are 2 types of technologies to achieve this:

– very wide field of view (“fisheye”) camera,

– 360° rotating camera.

Fisheye camera
This solution seems to be, at first hand, the most obvious and simplest one. However, the performances are not sufficient enough to reach the requirements in terms of detection range because:

– the resulting image is seriously degraded by optical distortion due to the “fisheye” wide angle optics.

– The single Focal Plane Array detector onto which the extended scene image is focused is IR type and therefore limited in pixel numbers. Indeed, up to now, the number of pixels available (say 300 000 pixels) for IR detectors is far less than that available for FPA in the visible spectrum. In addition, since the camera mirror optics field of view is hemispherical, the resulting image onto the detector is annular and therefore cannot cover the complete array, reducing further the number pixels used from 300 000 to say 200 000 (see sketch).

360° rotating camera
By contrast, this solution can result in a high resolution (high number of pixels) nondistorted image. Hence the choice made by HGH France to develop a camera (VIGISCAN) based on this concept.

The VIGISCAN Panoramic Camera
Based on the rotary high speed scanning principle, the 360° image has up to 12 Mpixels, i.e. somewhat 60 times higher than “fisheye” devices. The sensor continuous rotation (1 rps) ensures real-time monitoring, the infrared image being refreshed every second.

Equally important is to have high thermal sensitivity, i.e. the ability to detect tiny temperature differences. As an example, a man whose body temperature is 37°C in a tropical environment of 35°C will not be detected with a camera which thermal sensitivity is 1°C, whatever the image resolution is.

In this respect, there are two infrared technologies competing between each other:

− cooled infrared detectors, with high thermal sensitivity

− uncooled infrared detectors (cheaper) with low thermal sensitivity.

VigiScan is equipped with a cooled detector which thermal sensitivity is 0.03°C.

Hardware Description

− the rotary head of the sensor can be vertically tilted (±20°) for change of the line of sight.

− the sensor is connected via TCP / IP Gigabit Ethernet link to a laptop or PC in the control room. The connection may be landline, wireless or fibre optics.

− the camera power supply is 24V (3A) and therefore can be operated as a standalone device (batteries).

− MIL-810F Standard compliant.

− data can be compressed and transmitted through MJPEG video format by internet streaming, while maintaining the same detection performances. Transmitted videos may also be saved by standard digital recorders in a format fully customizable by the user (4/3 - 16/9 or any others).

Data processing and visualization
The acquisition and processing PC is equipped with visualization software (Windows 7 based) dedicated to give the operator the expected information in the clearest and simplest way.

Software display includes a low resolution banner 360° view and a panoramic annular view, which enables the operator to quickly select (mouse single click) an area of interest within the image. That area of interest is instantaneously displayed in maximal quality. In essence, the software behaves as a pan-&-tilt camera, even though for Vigiscan, the camera orientation is virtual and digital. Therefore, the view changes are instantaneous and areas in multiple directions can be displayed simultaneously (which cannot be done with a pan-&-tilt camera).

The operator can open an unlimited number of zoom windows, select the best colour palette according to his need and perform a manual or automatic contrast adjustment. The GUI is flexible and configurable by the operator. According to his preferences, he can place the different windows anywhere into the single or multiple screen display, without limitation of number.

The operator controls the camera operation from the PC. The automatic intrusion detection module can be activated or deactivated. A user-friendly popup menu enables to define the detection criteria according to the user’s needs. The detection can be activated into the whole image or only user-defined polygonal areas. A proprietary algorithm enables to eliminate the false alarms due to moving trees, waves, etc.

A tracking function enables allocation of a dedicated tracking number to each intruder. Panoramic display and intrusion detection are both operating simultaneously, whatever the number of intrusions over 360° are.

Advantages

− No special skill required. Vigiscan was designed for easy use and installation by unskilled operators.

− Overall cost reduction. In protection of critical industrial infrastructures, two or three Vigiscan cameras will replace dozens or hundreds of conventional cameras thus reducing the overall cost by 3 to 4 fold.

− Rapidity of implementation. When mounted on a telescopic itself mounted on a vehicle, the whole system can be put into operation in less than 10 minutes. This is ideally suited to the surveillance of wide area such as mobile military camps, border patrol, security of VIP events, temporary surveillance of planes on the ground at unsuitably secured local airports, etc.

− High sensitivity to abnormal scene temperature changes. For zones prone to risks of fire or explosions, such as power plants and oil&gas industrial sites (oil rigs, refineries, LNG terminals, pipe lines, etc.). Vigiscan can be used for fire detection as well as perimeter security.

− Ideal for wide and flat area monitoring, such as airports or borders. For maritime applications it can be located on the coast for seaport surveillance or ship-borne, fitted with a gyrostabilized platform, for anti-collision, fight against piracy, sea rescue and navigation assistance.

− Software Development Kit (SDK) available. This is for integrators wanting to develop their own GUI or use their own detection algorithms.

Conclusion
HGH France managed to fill the empty gap of long range fast panoramic surveillance by designing and now marketing their VigiScan camera, a unique and versatile product which suits many applications for Defence as well as Industrial and Commercial.

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Posted by Lee Mather

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