Surveillance made simple
- By Michelle Speir
- Nov 16, 2003
Given today's heightened concern about security, many agencies and departments are looking for dependable and economical surveillance systems. Better systems come network-ready so that they can be managed from existing computer resources.
When choosing a surveillance system, many factors must be considered. For example, does the existing network have the bandwidth to handle high-resolution images? Will extra software need to be installed? Do you want to record an area constantly or only when an event occurs, such as a car driving past? You should also consider features such as alarms, night vision, infrared motion detection, panoramic vision and zoom capabilities.
Management is another consideration. Is localized management enough, or do you want remote users to have access to the system? What is the system's compatibility with standard operating systems and other software? Is there room for future expansion and additions as technology advances?
These are some of the questions agencies must answer before choosing a surveillance system. Each installation has its own special needs, and once those needs are outlined, an agency can search for a system that meets them.
The German company Mobotix AG offers a low-cost, easily deployed network camera solution. This plug-and-play camera requires no extra software besides a Web browser and no external power source. All the necessary software is inside the camera itself, along with 64M of RAM and 8M of flash memory. The camera draws power from the Ethernet connection.
The camera is a network closed-circuit television (CCTV) system that can also run over ISDN, although this is much more common in Europe than in the United States.
If you need to install the camera outdoors, you can do so in almost any environment. It's advertised as weatherproof with an IP 65 rating, meaning dust or water can't penetrate or damage it. Its operating temperature ranges from minus 4 degrees to 140 degrees Fahrenheit.
The heart of the system is the Web capability that allows users to view images from any location with an Internet connection, although this feature is not unique to Mobotix. The camera has a fixed IP address that enables live remote viewing, and it can also transfer images to a Web site at regular intervals via FTP.
We tested the camera on a stand-alone PC, and it was a snap to set up. The camera plugs into a small Ethernet power adapter via a network cable. Another network cable runs from the power adapter to the Ethernet card on the PC. Then we simply entered an IP address and subnet mask into the TCP/IP properties, and we were ready to go.
When networked, one of Mobotix's strong points is that it does not overload the bandwidth because the image processing and video management take place inside the camera. It uses the network only when externally storing a predetermined image or sequence. It can even bridge network failures thanks to its buffering system. According to Mobotix, sending high-resolution live images, such as 640 x 480, at the highest frame rate takes up about 2 percent of a 100 megabits/sec network.
The system features a unique backlight compensation feature, and in our tests it performed as advertised. Unlike most cameras, this one does not have an auto iris. The iris determines the amount of light let into the camera. When an auto iris views an image with a bright background, it darkens the image to compensate. The result is usually a foreground or subject that is too dark — in some cases it's merely a silhouette. For example, imagine a person standing in front of a bright window.
Instead of the auto iris, the Mobotix camera lets you choose exposure zones. This means you can exclude certain parts of the image from exposure measurement. In the case of a room with a bright window, you could exclude the window and focus only on the foreground. This results in a viewable foreground — the interior of the room — and an overexposed window area, which doesn't matter since that area is irrelevant to the surveillance.
In our tests, we aimed the camera at a street scene with sunlight shining into the camera. Instead of being blinded, the camera compensated for the bright light and we were able to clearly view houses in the foreground.
Mobotix's dual lenses add a great deal of viewing flexibility. Our review unit came with a wide-angle lens and a telephoto lens, but a night lens designed for low-light conditions is also available. Customers can order the camera with any two of the three lens types.
You can simultaneously view images from both lenses, either side-by-side or as picture-in-picture. One quick click in a drop-down menu changes the view almost instantly.
Mobotix cameras are not capable of swiveling; instead, the company recommends installing two cameras facing in opposite directions to cover a larger area. The advantage is a lack of moving parts that may need servicing or that could malfunction, but this setup may be more expensive than buying one pan/tilt camera from another vendor, depending on the features you need.
The Mobotix software, accessed through a Web browser, is logically organized and easy to navigate. It contains all the standard surveillance functions, such as recording, playback and a buffer that can store a sequence before and after an event.
For installations such as garage doors, where events occur intermittently, you can set an event alarm. The camera will only record events, which would be cars driving in or out in this case.
The model we reviewed contains 36M of internal image storage and can store approximately 600 event images in 640 x 480 resolution or 2,400 images in 320 x 240 resolution.
We think the Mobotix surveillance system is well worth considering. It's well-made and easy to install and use, and all of its models are weatherproof. The system sets itself apart from others on the market with its backlight compensation feature, made possible by the lack of an auto iris. Other than that, it's in line with other cameras on the market regarding features and price. Because Mobotix cameras do not pan or tilt, you would have to buy at least two for whole-area coverage.