Thermal Myth No.4 ~ 'OEM products are just as good as leading brand products and less expensive'

Only a limited number of manufacturers have the know-how and facilities to produce the high quality cores which make thermal imaging possible. OEM manufacturers are dependent on this limited supply of bought-in cores, and often don’t have access to the latest technology. So, for example, a major networking specialist now offers a networked thermal imaging camera – a nice idea and marketed at a good price point – but it uses a core that has half the resolution of the FLIR cores (320 x 240 pixels). The result is a lower resolution picture that is harder to work with and may be less effective when it comes to detecting, recognising and identifying potential threats. For the buyer, it’s always a good idea to check the specification of the camera to make sure it provides the highest resolution images.

Another factor to consider is what do you want to do with the captured images? With FLIR users benefit from the Digital Detail Enhancement function in the GUI: this is a very effective algorithm that helps overcome low contrast and preserve details in high dynamic range imagery. 

If you are tempted by cheaper, OEM products, the best advice is to get a look at some end results before you buy. When you see it, the difference is clear. The best, specialist technology will pull out detail from the scene and overcome difficulty with contrast that leaves OEM units struggling.

Myth No.6 ~ 'Real-time recording can't be achieved with IP'

With IP we can choose exactly what sort of ‘real-time’ recording we want, tailoring the system to the application.

What do we mean by real time recording? According to the theory of persistence of vision, the human eye retains an image for a brief moment. When a series of still video images is displayed in quick succession, we get an illusion of movement (that is, we do not see the individual frames in the series).

When is real-time recording important? It is considered vital in high security applications and also
when monitoring financial transactions. Any process where it is critical not to miss any information, such as at a casino gaming table, should also use real-time recording. For most general security and surveillance applications, however, 24-hour real-time recording is not required, and generally means massive amounts of irrelevant information are being needlessly recorded and archived. It is far better in these instances to record in real time against an alarm or video motion detection.

It is essential that we don’t miss any critical information, but recording irrelevant and redundant information is a waste of money and clutters up systems. So how do we balance the two? We recommend that for high security and high speed transactions, video cameras are recorded at 25 ips, and for general applications images are recorded at 6 or 12 ips, increasing to up to 25ips
in the case of alarm or activity. 

In the PAL television system used in Europe, ‘real -time’ video records at 25 frames per second. A
technique called interlace uses persistence of vision to combine two consecutive images (or fields) to create one frame with higher detail in non-moving areas. Because the fields are exposed and displayed separately, a single TV ‘frame’ can potentially contain motion or even two distinct images, with ‘combiartifacts’ being seen on a still image where a recording system has combined the two fields. Modern IP cameras now use non-interlaced or progressive scanning for transmitting moving images in which all the lines of each frame are drawn in sequence. Real-time recording, however, is still considered to be 25 ips.

Thermal Myth No.3 ~ 'You need a hard-to-obtain licence to use thermal imaging cameras'

This is no longer a problem because the restrictions on exporting thermal imaging technology have been greatly relaxed. Producers such as FLIR offer products which operate with refresh-rates of either 9Hertz (standard) or 25 Hertz (advanced). The 9 Hertz technology is perfect for most commercial applications and is readily available without undue red-tape. For some specialist applications the faster, 25Hertz refresh rate may be desirable (for example, for use in monitoring fast-moving vehicles, industrial processes etc). But even in these cases an end-user statement will now normally be sufficient for approval by the US authorities.

The 25 Hertz products tend to be more expensive, and one reason is that there may be more administration involved in exporting them, but this need not be a major obstacle.

Myth No.5 ~ 'IP CCTV system have high storage costs'

Storage costs are now very affordable and are decreasing further, with HDD storage relatively inexpensive and NVRs allowing flexible, tailored recording schedules.

IP CCTV systems store video recordings on hard disk drives (HDDs). HDDs were originally developed for use in the computer industry, and the cost per Gigabyte of storage continues to go down year on year. This trend is almost certain to continue, irrespective of whether the hard disk is contained within a PC, network video recorder or other storage device.

Although hard disk drive storage costs continue to go down, it is worth having an archiving plan to ensure that vital information is retained, and unwanted information is neither recorded nor retained. A RAID5 system can be used to provide essential back-up in case of HDD failure. This is especially useful as we move to larger and larger drives (1Tbyte) and beyond, as fewer drives are used in the system. It’s possible to implement RAID5 by adding one extra drive.

Modern NVRs can record to a schedule, against an alarm trigger or against video motion detection (VMD), and the recording quality and frame rate set accordingly. Many modern security systems for corporate applications record high quality images in real time against VMD during the day, and high quality images at 13 images per second (ips) continually out of operating hours.

As HDD storage is relatively inexpensive, the main criteria should be to ensure that the storage is reliable. Many industry pundits consider that purpose-built professional network video recorders and expansion

bays offer the most reliable hardware for IP CCTV system image storage.

Thermal Myth No.2 ~ 'The technology is difficult to understand, and requires specialist knowledge'

Anyone who can install or work with a conventional CCTV camera will find that they easily get to grips with thermals. The obvious difference is that thermal cameras work by capturing images in a different part of the electro-magnetic spectrum to visible light – an infra-red wavelength that our eyes can’t see. This part of the spectrum may be invisible but there’s nothing mysterious about it.
 

In fact many of the key installation considerations are the same. For example, thermal cameras need to be set up, powered and linked to a network just like any other camera, and they produce composite video signals which have the same transmission requirements as ordinary CCTV data.

Once the system is up and working, easy adjustments can be made to the way that thermal signals are translated into visible pictures, tailoring the output to the user’s requirements. Again, it’s not difficult to master. 

And the units don’t require special handling. Good ones are robust, as you’d expect from products that originated in military applications, and their cores are as well protected as the CCDs in CCTV cameras.

Myth No.4 ~ 'IP CCTV systems have slow transmission'

Dedicated camera networks can easily cope and deliver excellent video streaming. Wireless networks are a bit slower but are delivering increasingly useful results where cable can’t be used. Currently, broadband internet viewing is limited to a few frames per second, but upload speeds will certainly continue to increase.

In IP CCTV, bandwidth refers to the data transmission rate of a signal, measured in bits per second. Local area networks typically have speeds of 100 Mbps (fast networks) or 1000 Mbps (Gigabit networks). This means that dedicated camera networks, particularly those using an Ethernet backbone, will easily cope with multiple camera locations each streaming less
than 2 Mbps.

Wi-Fi networks have maximum data speeds of 11 Mbps (802.11b) or 54 Mbps (802.11g). Wireless can be very useful where cable cannot be easily or cost-effectively installed, but specialist help should be sought for multi-camera links.

Broadband internet download speeds typically range from 1Mbps to 20 Mbps. Upload is different, and maximum ADSL upload speed where data is sent from a local system (e.g. CCTV system) to a remote system (e.g. remote viewing PC) is 512 kbps. With SDSL broadband, upload and download speeds are the same and are typically up to 2 Mbps.  

ADSL broadband is useful for remote viewing of images but, as can be seen from the above figures, upload speeds are limited to only a few frames per second. Until ADSL upload speeds are improved, the only ways to increase remote viewing speeds are to bond multiple ADSL lines together, subscribe to an SDSL line (where available) or subscribe to a leased line.

Thermal Myth No.1 ~ 'Thermal imaging cameras are too expensive for commercial use'

An individual thermal imaging camera may be more expensive than a single CCTV camera but if deployed in the right way, thermal technology is an affordable option that can undoubtedly save you money. The key cost advantage of thermals is that fewer units can be deployed to provide effective surveillance of a given area. For example, a single, top quality thermal unit will do the work of several conventional CCTV cameras when it comes to perimeter security, or open area protection. With effective threat-detection ranges measured in kilometers, thermal cameras are also more affordable than measures such as buried-cable systems, or fence-detection technology. And with fewer units required, groundwork and installation costs are reduced. Thermal cameras don’t require additional lighting to be installed, which saves on up-front costs and on ongoing running costs.

In weighing up the cost of thermal imaging cameras versus alternatives, a careful analysis of the true, total cost - including purchase, operation and maintenance - reveals that thermals are very often best value. And it’s also worth remembering that the cost of good quality thermal surveillance is also coming down, thanks to the introduction of competitive options from companies (for example FLIR’s H-Series hand held camera and D-Series internal PTZ camera) which, though more economical, still incorporate high-end technology.