Hi-Tech Security Solutions looks at what is cooking in the thermal camera market.
Thermals are becoming cheaper and are receiving rave reviews from a multitude of users in a variety of industries. Hi-Tech Security Solutions delves deeper into the technology with the help of some local experts. And, if you want to know more, the archive of our Thermal Webinar is available on securitysa.com/webinars.
Hi-Tech Security Solutions: What is a thermal camera? What is the difference between thermals and traditional IR devices?
Tanli Lundgren, C3: A thermal camera or forward looking infrared, is a device that forms an image using infrared radiation. Infrared radiation is emitted from all objects in the form of heat or energy. The heat emitted is not in the visible spectrum but in the infrared spectrum, which is invisible to the human eye. In general, the hotter an object is, the more radiation it emits. A thermal imager is a product that collects this infrared radiation from objects in the scene and creates an electronic image.
The real difference between thermal cameras and IR devices has everything to do with the spectrum of infrared energy. The spectrum is divided into three categories:
1. Near infrared (closest to visible light).
2. Mid infrared and (remote controls and a variety of electronic devices work in this spectrum).
3. Thermal infrared. (occupies the largest part of the IR spectrum).
IR devices work in the near and mid level infrared and still require some sort of ambient lighting in order to see. IR devices try to generate their own reflected light by projecting a beam of near-infrared energy that their imager can see when it bounces off an object. This works to a point, but the cameras still rely on reflected light to make an image, so they have the same limitations as any other night vision camera that depends on reflected light energy. The key difference between thermal IR and traditional IR is that thermal IR is emitted by an object instead of reflected off it. Infrared light is emitted by an object because of what is happening at the atomic level.
Thermal cameras also use a completely different type of image sensor than IR cameras. IR cameras have CCD or CMOS image sensors. The CCD and CMOS image sensors are inherently IR sensitive. Thermal cameras have a microbolometer image sensor, which consists of thousands of tiny sensor elements. Each element has a micro-resistor which changes its resistance as it heats up. The thermal camera focuses heat onto the elements, which in turn heat up. The camera reads the changes in resistance to calculate the thermal image.
Only thermal imagers can see in absolute darkness and perform well in adverse weather conditions due to the fact they do not rely on light but rather emitted energy. The infrared wavelength can penetrate smoke, rain, snow, blowing sand and foggy conditions. Thermal imagers also allow us to see heat signatures left by hand or footprints and many other scenarios that we would not be able to see normally in the visual world.
Roy Alves, Axis Communications: A thermal network camera is a camera that creates images based on heat that radiates from any object, vehicle or person. Thermal images are not dependent on visible light; instead, images are created by operating in the infrared spectrum. It works perfectly well even in total darkness since the ambient light level does not matter. A traditional IR device and illuminators provide additional light in applications where the surrounding lighting conditions may be insufficient for effective video surveillance. As the camera can ‘see’ some infrared light that is invisible to the human eye, there are various alternatives as to how this can be displayed on a computer screen. Usually the image is shown in black and white, with the scene appearing as it would if the human eye could see infrared light. Other false colours can also be used to show the content of infrared light compared to visible light.
Philip Smerkovitz, TeleEye SA: A thermal imaging camera captures infrared energy emitted by an object. All objects above zero degrees Kelvin emit infrared energy. This infrared energy is then focused by the optics onto an infrared detector. The detector sends the information to sensor electronics for image processing. The electronics translate the data coming from the detector into an image that can be viewed over both analogue and IP video equipment or computers.
Because everything generates heat, thermal security cameras can see as well at night as they can during the day. Traditional cameras dependent on visible light are useless at night or in poor visibility without supplementary illumination from lights or lasers. This is where the traditional IR cameras have been applied.
Traditional IR cameras feature banks of LEDs which emit infrared illumination into the area in front of the camera. The LEDs are often placed around the lens of the camera. LED illumination is compromised by limited range performance. Also for the longer range or higher power LED illuminators, moisture such as mist and fog or rain on objects causes reflection of the infrared illumination back into the camera which causes the shutter to close resulting in loss of important details in darker scenes. The more infrared illumination you throw on the scene, the worse the problem becomes.
Thermal imaging cameras on the other hand produce crisp images in the darkest of nights. Contrary to other technologies, thermal imaging cameras need no light whatsoever to produce a crisp image. They can see through smoke and most types of fog/haze, in practically all weather conditions.
HSS: What scenarios are thermal cameras suited to? Day/night/low-light?
Tanli Lundgren, C3: Everything you see in normal life has a heat signature. Many of the objects you could be looking for, like people, generate their own contrast because they generate their own heat. Thermal imagers can see them well because they do not just make pictures from heat; they make pictures from the minute differences in heat between objects. Without a doubt, thermal cameras are the best 24-hour imaging option.
Roy Alves, Axis Communications: Thermal network cameras are best suited to secure an area or a perimeter in complete darkness or challenging weather conditions such as heavy fog, rain or snow.
Philip Smerkovitz, TeleEye SA: Thermal imaging cameras perform equally well in the day and night, making them ideal for many applications including government and military, commercial security, automotive, marine and thermography applications to name a few.
HSS: What are the decision points when considering a thermal or optical HD camera?
Nick Grange, C3: The statement ‘horses for courses’ rings true, thermal cameras would be used in situations with no or low light as well as applications where long ranges need to be covered. It allows the user to interrogate the footage with great detail due to the high resolution or pixel count of the recorded footage.
Roy Alves, Axis Communications: It is important to remember that a thermal network camera is best suited to complement a professional IP surveillance system. Thermal cameras do not, however, deliver images that allow reliable identification – that is why thermal cameras and conventional cameras complement and support each other in a surveillance installation. Depending on the user’s requirements, a thermal network camera would best be suited for detecting an object while an HD offering would then be used in conjunction with the thermal camera for reliable identification.
HSS: Do you have any examples of thermals in use today?
Tanli Lundgren, C3: C3 has numerous sites where we have successfully implemented thermal cameras combined with intelligent video analytics as part of the perimeter security solution. These sites range from the tunnels of the Gautrain, perimeters of large residential and golfing estates, power stations, numerous gold and copper mines, precious metal refineries and classified national keypoints.
C3’s thermal cameras were chosen for the Gautrain project after an extensive testing period between similar technologies. The results were sent over to France for the final decision to be made. C3’s Opgal thermal cameras combined with ioimage intelligent video analytics were the chosen technology.
Roy Alves, Axis Communications: TVMS used our thermal network cameras at the Sasol Ammonia plant in Sasolburg. These cameras are used for general monitoring of the facility as well as temperature monitoring. The fluctuation in temperature affects the stability of the product and also affects the quality of the end product. TVMS was able to recommend Axis thermal network cameras to Sasol to monitor these temperature fluctuations.
The second advantage with using thermal cameras is to monitor the flames emitted outside the processing area. These flames can, if too large, cause damage to the facility and staff, in both cases it is impossible to monitor with the naked eye as it is an invisible gas. However, with thermal imaging the camera is able to alert the operator if the temperature and flame size grows too large. The operator can then alert the processing plant accordingly and avoid unnecessary damage to property and loss of life.
Philip Smerkovitz, TeleEye SA: FLIR has been used worldwide in a wealth of high security applications from ports and harbours to nuclear facilities, power stations and even residential installations.
HSS: Are there any other facts about thermal technology you think our readers should know?
Tanli Lundgren, C3: A couple of important interesting facts are:
1. Thermal cameras are more energy efficient and cheaper to run than the CCD/IR illuminator option. We did a costing exercise last year comparing the energy costs between thermal cameras on a 4 km perimeter and CCD IR illumination. The annual electricity costs to secure a 4 km perimeter using the CCD and IR illuminator combination was an estimated R18 266,69 compared to the thermal camera option of only R1178,50.
2. You need less thermal cameras to secure a perimeter than you do CCDs. Thermal cameras, with a clear line of sight can cover 400 metres in total darkness (using various lenses you can of course increase this figure) with an overlap of 50 metres between cameras. In order to secure a 4 km perimeter you would need 10 thermal cameras. CCD cameras cover about 60 metres, which is the acceptable standard when combined with intelligent video analytics. Of course, CCD cameras need help in order to ‘see’ intruders at night and for this reason they are often combined with infrared illuminators. So, over a 4 km perimeter you would need approximately 60 CCD cameras plus 60 infrared illuminators.
3. When purchasing thermal cameras, it is imperative to check support in SA, most suppliers have to send faulty stock back to their overseas manufacturers and have no strategic spare or repair capabilities in SA.
Philip Smerkovitz, TeleEye SA: The one area that needs to be highlighted is the perception people have of the cost of thermal. We can show that the TCO for a thermal installation is lower than conventional CCTV equipment due to the superior range performance under all lighting and weather conditions. If we look at both entry-level and high-end products, a FLIR F-112 19 mm camera which retails for around R45 000, can detect a human up to 300 metres, while the same coverage using static CCTV cameras would require at least six cameras spaced every 40 to 50 metres. The cost of cameras, poles and reticulation far outweigh the cost of a single thermal installation.
At the higher end the FLIR F-304 100 mm camera, which retails around R200 000, offers human detection up to 2 km. Anyone who has been quoted on CCTV perimeter detection for this distance using conventional cameras understands that FLIR thermal cameras are a far lower cost alternative that produces superior verification images.
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