Selecting the most suitable cameras to monitor large areas
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With system designers having so many options when it comes to specifying the most appropriate cameras to monitor large areas, Uri Guterman, Head of Product & Marketing for Hanwha Techwin Europe, provides an overview of the merits of some of the most suitable camera formats.
PTZ cameras have traditionally been used for city and wide area surveillance applications such as airports, car parks, shopping centres, sports stadia and warehouses, with operators able to track the movement of objects and zoom in to observe close-up detail of any activity.
The ability of an operator to proactively monitor an incident and zoom in to verify what is occurring, ensures they are able to quickly decide on the most appropriate response. In addition, many PTZ cameras feature auto-tracking, as well as continuous pan and pre-set positioning, which means that images of a moving object will be captured and recorded even when operators are distracted or are away from their workstations.
The deterrent effect of PTZ cameras configured to automatically tour an area should also not be underestimated as they will create a strong impression to would be offenders that they are being watched, even if the images captured by the cameras are not being monitored in real-time.
Whilst it should be emphasised that PTZ cameras still have a big part to play in detecting anti-social or criminal activity, recent advances in video surveillance technology has meant that system designers now have the option to consider specifying other types of cameras which, depending on the application, might be more suitable. The sharpness and clarity of the images captured by 8K video surveillance cameras, for example, simply ‘need to be seen, to be believed’.
In reality, very few users are likely to deploy 8K cameras with the intention of just monitoring an entire field of view. The value of these cameras comes from the fact that 8K is the equivalent of 16 x 1080p Full HD images and this means that a single camera can capture a vast amount of information, enabling operators to digitally zoom into a very small part of the scene without any pixilation of the image. For this reason, a football stadium is an excellent example of where an 8K camera can be put to very good use as it would be capable of capturing evidence grade images of 20,000 or more fans occupying a football stand. As such, its price/performance ratio makes the 8K camera a viable, cost-effective alternative to the deployment of multiple fixed or PTZ cameras.
‘Horses for courses’
When it comes to deciding whether an ultra-high resolution 8K or PTZ is the best camera format for any given location, it will very much depend on what the end user wishes to achieve. However, budget limitations also need to be taken into consideration. In simple terms, an 8K camera is a highly impressive, high performance option if there is a requirement to continually record a camera’s entire field of view at the same time that an operator might need to zoom into a specific area of interest. However, PTZ cameras are a much lower price option and are ideal for when operators need to constantly scan a wide area of view, whilst having the flexibility when necessary, to quickly zoom in to see what may be occurring in greater detail.
The case for PTZ cameras is further strengthened when real-time monitoring is more important than recording video for evidence purposes and equally important, the latest generation of PTZ cameras are equipped with adaptive IR technology which adjusts the angle of the camera’s built-in IR LEDs to match the level of zoom.
Multi-sensor, multi-directional cameras
Multi-directional cameras typically offer the capabilities of two, three or four video surveillance cameras in a single housing and yet, as they only have a single IP connection, you will only need to purchase one VMS license.
Those equipped with two separate lenses are designed to capture high definition images of adjacent areas. Depending on the required field of view, there is a choice of interchangeable lens modules which can be easily fitted on site by an installation engineer. These multi-streaming cameras significantly reduce the costs which would normally be associated with installing two separate cameras to monitor, for example, an L-shaped area such as two sections of a corridor or two sides of a building.
There are also multi-directional cameras available which feature four separate sensors, with operators able to choose from a broad range of customisable angles and zoom settings per sensor. This offers cost savings for both system integrators and end users, as multi-sensor cameras use less cable, conduit and mounting hardware, compared to what would normally be required to enable up to four separate cameras to do the same job. With less network connections, they also require fewer switches.
Designedfor monitoring large open areas with just one camera, the images captured by the four sensors can be seamlessly stitched to produce a panoramic image covering up to 220°images.
Life will also be much easier for installers if models equipped with motorised PTRZ gimbals are specified. These will reduce on-site times as they enable engineers to remotely pan, tilt and rotate the lens’ positions in order to set the camera’s field of view.
It is worth noting that some manufacturers, such as Hanwha Techwin, offer 4 channel multi-sensor cameras with an additional integral PTZ camera. This can be configured to automatically zoom in and track a moving object or move to a user configured pre-set position when the motion detection function of one of the four camera sensors detects activity.
This addition of a PTZ camera means users are able to avoid incurring the higher capital, installation and maintenance costs of deploying five separate cameras to cover a large area, whilst achieving the same level of functionality.
A single 360⁰ camera will quite often offer the most efficient and cost-effective way of monitoring a large area and particularly so when a number of standard cameras might normally be required to avoid any blind spots. They also offer a compact option for retail stores and other environments where aesthetics is important.
Savings can be achieved on maintenance costs compared to other types of cameras, as 360⁰ models have no moving parts.
Most 360⁰ or ‘fisheye’ cameras offer a variety of alternative viewing modes, including single panorama, double panorama and quad views. They are also likely to feature a digital PTZ which allows operators to electronically pan, tilt and zoom in on specific areas for a more detailed view whilst continuing to monitor and record the whole 360-degree view.
Some of the cameras will have onboard de-warping functionality. Where this is not the case, video management software, such as Wisenet WAVE, can be used to de-warp the fisheye images.
Spoilt for choice
With so many different camera formats to choose from, consultants, system designers and integrators have an interesting challenge in deciding which cameras will best meet the requirements of a specific video surveillance project.
To a large extent, the decision can be logically made with the help of the risk assessment process and by taking into account an end user client’s operational requirements. An 8K camera, for example, would seem the obvious choice when there is a need to monitor large crowds of people in wide open areas, whilst multi-directional cameras are ideal for capturing images of adjacent areas. PTZ cameras are likely to be strong contenders when the captured images are to be viewed in real-time, as they will provide operators with a high level of control and enable them to proactively track the movement of people. Their greater deterrent effect should also not be underestimated.
In reality, a combination of two or more of these types of cameras is likely to be required for most high security or mission critical applications and there is a multitude of other factors to be considered before deciding on the best cameras for a specific project. These include, for example, the required image resolution and if there is a need for the cameras to have built-in IR illumination so that they will capture high quality images regardless of the light levels. The need for video analytics and whether the cameras have the ability to support third-party specialist applications should also be considered, as should bandwidth requirements.
As always, the best advice is to work with manufacturers you believe you can trust and ask them to provide live demonstrations of the various camera types. This will allow you to make informed judgements on which cameras have price/performance ratios that will match your specific requirements.
Do you have some questions about the latest generation of video surveillance cameras? Email Uri Guterman at [email protected]