Below is an older video surveillance article. Video Surveillance technology has advanced dramatically, since it was written, however I felt it was important to keep older information on the website, for informational purposes.
The starting point of any C.C.T.V. system is the camera. Simply stated, a camera is a light sensitive device that converts particles of light into electrical impulses, however, there is a vast difference in the quality of cameras available to the consumer. Factors that differentiate the various cameras include whether they are colour, black and white, light sensitivity, image resolution and image transfer technology. The consumer must also consider the inherent advantages and disadvantages in each of these different camera technologies and decide which features best fit their individual needs and goals.
In the past, color cameras have been both very expensive and lack-luster in their image performance, when compared to black and white cameras. New technology is now bringing the innovative technologies closer together in both the price and performance scale. The current differences between the two technologies are almost entirely limited to light sensitivity and light reactivity.
Light sensitivity is measured in LUX. The lower the LUX rating, the higher the sensitivity to light. It is important to keep in mind that even the best-rated cameras are limited by the technology of the day, as well as the visibility conditions present at the time of the surveillance. Although great advancements in low light surveillance continue to be ongoing, the image quality in a low light situation will rarely be up to the standards of daylight surveillance.
Color cameras, although much more appealing on the outside when compared to their black and white counterparts, generally offer less low light sensitivity than a black and white camera. The other advantage of black and white cameras over colour cameras is its ability to "see" infra-red light, which is invisible to the human eye. You can test this by aiming a standard television remote at a black and white camera while watching the monitor, the flashes you see are bursts of infra-red light. The advantage of this becomes apparent in the ability to light up a dark area with infra-red light, thus making images visible in almost pure darkness. With the colour camera the area will appear unlit, however, to a black and white camera, the area will appear almost like daylight.
The black and white camera's reactivity to the invisible light spectrum can also pose a disadvantage in certain applications. Infra-red light, although not visible to the human eye, is found in abundance in many everyday situations. For example, when aiming a black and white camera at hot pavement, it will "confuse" the camera resulting in an unbalanced image. Professional grade black and white cameras often incorporate infra-red cut-filters. These cut-filters inhibit the infra-red light spectrum in turn decreasing the cameras low light sensitivity.
The C.C.T.V. Industry measures image resolution in horizontal lines. The higher the line rating, the clearer the image will appear. With this fact in mind, consider that all electronic components within a C.C.T.V. System, from the camera, to the VCR, to the monitor. These items are all rated in the same way. The actual resolution of the entire system will only be as high as the lowest rated item. For example, if you have a camera rated at 450 lines and a monitor rated at 300 lines, then the result will be 300 visible lines of resolution because the monitor is the lowest rated item in this example. Another point to keep in mind is that the line rating is "Total lines" not lines per inch. Therefore a 12" monitor with a 300 line rating has a far better clarity than a 17" monitor with the same line rating.
The most recent and predominant advances in the C.C.T.V. Industry are the changes in image transfer technology. This technology deals with how the camera takes light particles and converts them into electronic images. Without going into too much detail, image transfer technologies include the following:
Phosphorus Tube Cameras - This camera has low quality, old technology and is susceptible to "image burn". Image burn is when intense light sources will burn themselves into the camera‚s light receptor resulting in the image appearing "memorized". Although this is not a problem with modern day cameras, image burn can still occur on monitors. Tube cameras are also known for poor low light sensitivity.
C.C.D - Also known as "Chip cameras". This camera is the most standard of cameras in the professional realm. C.C.D. cameras do not suffer from the problem of image burn and can incorporate various methods of signal processing, which offers a high level of flexibility to the installer.
CMOS Transfer Cameras - These cameras are very small and continue to get smaller as the technology advances. Although very attractive in their size, CMOS cameras generally do not offer the signal processing, image quality or low light sensitivity of the higher priced C.C.D. camera models. However, the technologies are slowly growing closer together to the point where CMOS cameras may eventually take over the Surveillance Industry.
The Surveillance Industry has continued to move towards the implementation of color cameras that switch to black and white, or even infra-red in low light conditions. Although there are some models currently available on the market, the technology is not at a point where it is affordable enough to be manufactured on a large scale.
Depth of Field - There are plenty of "good deals" on security cameras, out there. But how good is "good" and is the quality even acceptable as video evidence? When looking at a camera one needs to consider the lens. Most cameras available online or in big box stores are designed for the DIY market, for this reason they are made as close to plug and pray as possible. If you are goal is general surveillance, and your only concern is seeing if there is an object moving around the yard and if said object is a human or a trash panda, this type of camera will suit your needs. If, on the other hand, you are wanting to capture an image with sufficient detail to identify the person on your property, the wide angle focus free lens will leave you disappointed.
Unlike the human eye, a camera is incapable of rapidly shifting focus on the object of interest, for this reason the lens of the camera needs to be focused in on the area you expect the target to be. There is also a photography term known as Depth of Field, this is the distance an object will be in identifiable focus. Higher end lenses with glass optics are often designed to have a larger depth of field. Sure there are some manufacturers who try to wow the consumer with a high "megapixel" resolution, this resolution is meaningless if the lens is incapable of providing a detailed view. Basically you are paying for high resolution blur.
Image Compression - In modern digital video surveillance, images are often digitally compressed, in order to take up less space on the harddrive and to provide a higher frame rate. While this may seem like a positive, over compression can result in digital artifacts and pixel averaging.
Digital artifacts appear as foreign lines or dots in an image and are the holy grail for criminal defense lawyers, as they provide a clear (or unclear, as the case may be) pathway to reasonable doubt. Pixel averaging is just as detrimental as this results in the loss of shade and shadow detail, in favour of bright and vibrant high contrast images. While vibrant images may look great when looking at a flat object or single solid lines, the results are less desirable when dealing with the details of a human face.
In addition to saving space, image compression allows a manufacturer to increase the specified resolution (or megapixels) and still maintain an acceptable frame rate. Sadly, the end result is more often than not, questionable image quality.
IP Video Surveillance
Technology has advanced substantially, since this article was written, and KeepSafe Systems strives to be on the cutting edge of these product developments. Nowhere is this more evident in our implementation of Mobotix IP Cameras.
Manufactured in Germany, Mobotix goes beyond simple video surveillance and is designed with solutions in mind. With advanced features like edge recording, event based logic, 2-way voice, advanced analytics, thermal imaging and the ability to seamlessly integrate with many other systems, Mobotix is clearly more than a simple video surveillance system. That being said, the Mobotix system is easy to use and completely scalable.
Some interesting applications include detecting threats of fire with thermal imaging; proactive trespass notification / verbal warning; integration with lights, sprinklers, alarm systems and more. If you have a security concern, give us a shout and we can come up with a solution. The image to the left was taken with a Mobotix S16 camera. The discreet design enabled me to disguise the camera within the bushes, as not to disturb the growing family.
In addition to recording at the camera, Mobotix IP cameras are also remotely accessible through a free App (iOS / Android) and there is no additional monthly charge to access your cameras remotely. All you need is an internet connection.
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KeepSafe Systems installs and services residential and commercial security alarm systems and provides alarm monitoring services in the Metro Vancouver / Fraser Valley area of the Lower Mainland of British Columbia. Our service area includes but is not limited to Vancouver, North Vancouver, West Vancouver, Burnaby, Coquitlam, Port Coquitlam, Port Moody, Pitt Meadows, Maple Ridge, Mission, Abbotsford, Hope, Harrison, Aldergrove, Langley, Surrey, White Rock, Delta, Richmond and everywhere inbetween. Give us a call and let us help you feel more secure. We are here for you