Top 5 Ways

Jun 1, 2007 12:00 PM, By Fredrik Nilsson

Successfully deploying a surveillance system depends on assessing an organization's needs and identifying technology that works with existing systems and enables companies to scale to size over time. An IP-based surveillance system gives companies numerous choices related to network cameras, installation and video management software. Here are five things to consider in order to get the best results from a network video system:

Choose The Right Network Camera

There are several types of network cameras on the market that can be grouped together to complement each other's functions or can be used separately. Just keep in mind that what may work in an industrial setting, for example, may not be appropriate for a school system. Variations of network cameras include:

• Fixed network cameras, which have a body and exchangeable lenses of C/CS standard mount, and can be used in indoor and outdoor installations. People can see the direction the camera moves at any given time.

• Fixed dome network cameras, which are more discreet and non-obtrusive. The camera is pre-installed in a small dome housing, so people typically cannot see which direction the camera is pointing. Exchangeable lenses are somewhat limited because of the lack of space inside the dome.

• Pan-Tilt-Zoom network cameras, typically used indoors, are suitable for retail spaces because of their ability to follow a person's movement — either manually or automatically. Most PTZ cameras do not have full 360-degree pan and are not made for continuous automatic operations.

• Network dome cameras, which have the ability to pan a full 360 degrees and are good for continuous movement. Network dome cameras can cover an area that would require 10 fixed cameras to do the same job. The optical zoom typically ranges between 18x to 35x. When using zoom factors above 20x in outdoor installations, a built-in electronic image stabilization can be used to deal with vibration caused by wind.

Install It Right The First Time

Once the appropriate network camera or mix of cameras is selected, there are several rules that will help get the most from a network camera. Some of those rules include:

• Lots of light — If there isn't enough light, images will become blurred and dull in color.

• Avoid backlight — Light from a window behind an object can result in the image being overexposed.

• Reduce the contrast — Sometimes when a camera captures an image that is in front of a white or bright backdrop, the object appears dark. Switching the background color to gray instead of white can solve the issue.

• Use auto iris lenses in outdoor settings to adjust automatically the amount of light that reaches the image sensor. Doing so optimizes the image quality and protects the image sensor from damage from strong sunlight.

• Avoid direct sunlight in outdoor settings, which blinds the camera and permanently bleaches the small color filters on the sensor chip. If possible, position the camera facing the same direction as the sun.

• Avoid contrast problems in outdoor settings from cameras that have too much of the sky in view, often producing images that appear dark because of the automatic adjustments for proper lighting. Cameras should be mounted high above the ground on a pole or another sturdy mounting object so the view contains less sky and more of the desired environment.

• Keep reflections to a minimum when a camera is mounted behind glass by placing the lens close to the glass. Special coatings can also be applied on any glass used in front of a lens to further reduce reflections.

• Use additional external lighting for cameras that will be used at night, but avoid reflections and/or shadows. For stealth installations, infrared (IR) lighting may be better than normal lighting commonly referred to as “white light.”

Determine The Most Effective Compression Technique

As camera and network technology has improved with the use of Ethernet cabling and Internet Protocol (IP), the amount of information recorded and transmitted over networks has increased. Video compression, which reduces hard disk consumption and bandwidth demands, enables recorded information to be stored and transmitted in an efficient manner. The most common image compression techniques include:

• Motion JPEG (MJPEG) — MJPEG derives from Joint Photographic Experts Group or JPEG, which is the compression standard to achieve high-quality still images. MJPEG creates a digital video sequence using JPEG images and is the most commonly used standard in network video systems. It is suitable for quality control monitoring of products or when bandwidth cannot be guaranteed.

• Moving Picture Experts Group (MPEG) — MPEG is the best-known standard audio and video streaming technique used in surveillance situations that require constant high frame rate, high quality and the ability to guarantee bandwidth. There are several types of MPEG — MPEG-1, MPEG-2, MPEG-4. In surveillance, MPEG-4 is most common, and that comes in different versions including Part 2 (advance Simple Profile) and Part 10 (H.264).

When determining which type of compression to use, it is important to consider the level of resolution in video and audio, desired frame rate and the network capacity needed to monitor and play back video.

Video Management Software

Video management systems are the glue that enable users to monitor, analyze and store video output effectively. Companies can choose between two different platforms for network video management: PC Server platforms and Network Video Recorder (NVR) platforms. Both platforms are PC-based but the NVR comes as a hardware box with the video management functionality pre-installed, whereas the PC Server enables users to leverage their preferred choice of hardware, suppliers of IT equipment and maintenance services.

Leverage What Exists; Plan For The Future

If a company has an existing surveillance system in place that incorporates analog cameras, they can easily integrate those cameras into a network system using video servers. Video servers digitize and compress traditional analog video into storable digital data. In order to integrate the two, simply connect the coax cable from the analog camera to the analog input on the video server. The video server then connects to a network and transports the video over a local area network (LAN) or across the Internet. Once the video is on the network, it acts like a video stream coming from a network camera and will be ready for integration into the network video system. In essence, a video server turns an analog camera into a network camera.

IP-based systems not only work with analog technology, but they are also popular because they are easily scalable, allowing companies to take full advantage of a network video system. Power-over-Ethernet (PoE) and wireless installations provide companies with the flexibility to scale systems as surveillance needs arise and change over time.

PoE technology integrates power into a standard LAN infrastructure, enabling the device to be powered using the same cable used for the network connection.

Wireless networks are functional and financially feasible options for companies that do not want to install extra cabling, which can be intrusive and costly. With wireless technology, companies can install cameras in new locations or bridge two buildings or sites together without pulling new cables and without the need for expensive and complex ground works.

By carefully examining the needs of an organization and matching them with technology and applications that will be most effective, companies can thoroughly maximize the full capabilities of a network video system. The result will be a secure environment that is both functional and financially feasible for years to come.

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Fredrik Nilsson is general manager of Axis Communications.

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