Fredrik Nilsson is general manager of Axis Communications and an authority on IP surveillance.
When building a surveillance system, it is important to select cameras that meet the needs of your organization and installation. This includes selecting specific types of cameras to meet the locations where cameras are needed and the intricacies of the venue, including fixed, pan/tilt/zoom (PTZ), vandal-proof, or fixed-dome cameras.
There are all types of network cameras available today, and no matter what your needs are, a network camera is available to meet them. Although analog cameras are available in a similar variety, network cameras are now offering added benefits, including better image quality and more installation flexibility. And for some special applications, such as very high-resolution needs, or wireless, network cameras are the only option.
Selecting the right network camera is a critical for the success of your surveillance system. For example, retail environments will have different needs than schools or highway systems, and every installation has some features that are more important than others. Some may value off-site recording and storage over other features such as Power over Ethernet (PoE) or alarm management.
Off-site recording was particularly important to Todd Jacobson, the owner of a Citgo Sooper Stop in North Dakota. Within three weeks of installing a network video system, his convenience store was robbed. However, because the video was stored offsite, the thief was unable to steal the video tape during the robbery, as is common with traditional analog CCTV systems. Because of the high image quality and the offsite recording, police were able to identify and apprehend the perpetrator within four hours and Jacobson recovered all of the losses from the robbery.
This example also indicates that not all network cameras are created equal. If Jacobson had been using a low-end network camera, it is possible that image quality wouldn't have been good enough to help the police identify the thief. There are many components that go into creating a quality network camera, and security professionals need to understand how these components affect the camera's performance and durability.
Image quality: Image quality is the most important feature of any camera. This is particularly so in surveillance and monitoring applications, where lives and property may be at stake. Superior image quality enables users to more closely follow details and changes in images, making for better and faster decisions. It also ensures greater accuracy for automated analysis and alarm tools, such as object recognition.
When assessing image quality be sure to research the following factors: light sensitivity, the crispness of moving objects, and the clarity level. A camera's datasheet will tell part of the story, but it is a good idea to field test a few cameras before making a decision. In addition, there are some simple steps you can take to ensure high quality images - use enough light, avoid backlight and reduce contrast whenever possible.
It is also critical to take into account the location of the cameras, especially if the cameras will be used outdoors. An auto iris lens, which automatically adjusts the amount of light that reaches the image sensor, should always be used for outdoor applications. Direct sunlight should always be avoided. Mount the camera high above the ground to avoid a contrast effect from the sky. If the camera is mounted behind glass, the lens must be placed close to the glass to avoid reflections. If the camera will be used at night, an infrared (IR) camera should be used generate high quality images in very low light conditions.
Power over Ethernet (PoE): In most buildings today, TCP/IP infrastructure is available by means of Cat 5 and 6 cabling. The cabling can be used for fast transport of data, and the distribution of power to devices connected to the network, using PoE technology. PoE reduces installation costs by eliminating the need for power outlets at the camera locations and enables easier application of uninterruptible power supplies (UPS) to ensure continual operation, even during a power outage.
PoE technology is regulated by the IEEE 802.3af standard and is designed to not degrade the network data communication performance. When evaluating PoE-enabled network cameras, it is important to look for those that are based on the IEEE standard, to ensure that any brand network switch can be chosen, providing a truly open system.
Progressive scan: Progressive scan capability is found only in network cameras, but not all network cameras have this functionality. Progressive scan involves exposing and capturing the entire image simultaneously, as opposed to analog interlaced scanning which is the exposing and capturing of only half of the lines in the image and then the other half 17msec later. With interlaced scanning, if an object is moving the image will become blurry. In a progressive scan image all lines are scanned in perfect order so there is virtually no "flickering" effect.
While interlaced scanning may be sufficient under certain conditions, progressive scan technology allows for far better image quality on moving objects. In a surveillance application, this can be critical in enabling the user to view detail within a moving image such as a person running away or the license plate on a moving vehicle. When cameras capture moving objects, the sharpness of the frozen images depend on the technology used, and progressive scanning consistently produces the best results in clarity and recognizing important details.
JPEG/MPEG4 standards: It is important for any network camera to follow JPEG and MPEG-4 standards in their entirety. Many vendors claim compliance with a standard, but do not adhere to that standard 100 percent. Full adherence ensures the flexibility to use video for many different applications. It also guarantees that you can view the video many years from now. If a camera uses one company's proprietary compression technology and that company goes out of business, the video will be unreadable in the future. Also, if a company is following the MPEG-4 standards, ask if the licensing fees are paid, and how many licenses are included with each product. Proprietary compression technologies are also not always admissible in court, an important consideration for security and surveillance applications.
Extensive support of Video Management Applications: The security industry migration to network video includes the use of open systems and platforms. Make sure to select a network camera that has open interfaces (an API or Application Programming Interface), which enables a large variety of software vendors to write programs for the cameras. This will increase your choices in software applications and will ensure that you are not tied to a single vendor. Your choice of network camera should never limit vendor options and functionalities.
Vendor history and focus: It is important to make network camera decisions based on estimations of future growth and the need for added features and functionality. This means your network camera manufacturer is going to be a long-term partner. It's important to choose a solid partner, so be sure to look for a company that has a large installed base of cameras, is profitable, focuses on network camera technology, and offers you local representation and support. You want to choose a camera from a vendor where the innovation, support, upgrades, and product path will be there for the long term.
Just like with analog cameras, not all network cameras are created equal. Far from it, and the differences among network cameras are greater and more significant than buyers have experienced with analog technology. The end user has to be smart. Vendors will tell a lot of great sounding stories, but the user has to have a solid list of evaluation criteria, test the different choices, and understand the differences between the available products.
Network Camera Check List Suggestions
- Lens: F2.0 and auto iris for outdoor applications
- Image sensor: Progressive scan CCD image sensor or high quality CMOS
- Resolution: 640x480
- Frame rate: 30 frames per second
- Video formats: MJPEG & MPEG4 at Advanced Simple Profile level 5
- Power over Ethernet: 802.3af compliant
- Audio: G.711 or AAC-LC format
- Software compatibility: Open API supported by many Network Video Recorder software developers
- Security: Multi-level user name/password protection minimum and IP filtering and HTTPS for high security requirements
- Management: Built in web interface and multi-camera management application
About the author: As the general manager for Axis Communications, Fredrik Nilsson oversees the company's operations in North America. In this role, he manages all aspects of the business, including sales, marketing, business expansion and finance. He can be reached via email at firstname.lastname@example.org.