PAN, TILT, ZOOM BETTER THAN EVER
Feb 1, 2002 12:00 PM
By TOM PATRICK MCAULIFFE
The emergence of today's pan/tilt/zoom (PTZ) technology is making CCTV even more effective. Gone are the days of stationary black and white cameras unable to follow the action. Today's PTZ solutions can pan, zoom in on an incident or take in an entire area manually, randomly or automatically.
A PART OF THE WHOLE
While the security industry has focused on the integration of access control with CCTV, there has also been an emphasis on adding cost-effective PTZ capability to existing video surveillance cameras. Declining prices in PTZ technology have shifted product selection. Traditional building owners are often choosing to install a high-speed pan/tilt/zoom dome instead of multiple stationary cameras to cover the same or larger field(s) of view.
The use of a PTZ camera is not an effective way to eliminate multiple cameras. The cost for a PTZ camera is approximately three- to five-times the cost of a fixed camera, and the camera can typically view 180 degrees, leaving half of the scene unprotected.
A person willing to commit a crime or cause a problem is often able to see where the camera is aiming and consequently stay out of its line-of-sight. This is one of the reasons mirrored domed solutions have become so popular. A mirrored, bullet proof, plastic dome over the camera can keep individuals from seeing where the lens is pointed.
The view of PTZ cameras can be adjusted a number of ways: human manipulation, motion detection, door contact signals, or automatically to a pre-set pattern. Since security professionals are not always available to manually move a camera immediately to the point needed, sometimes problems are not seen or recorded. PTZ cameras can be programmed to oscillate automatically, but depending on where the camera is pointed, its view can be avoided. Constant oscillation also creates wear-and-tear on the camera motors, increasing maintenance costs.
Experts list three major concepts to keep in mind when considering a PTZ system for a security environment:
For example, a typical system for a major facility such as a hospital or school might have nine or 10 outdoor color cameras, each housed in a protective dome with heaters to keep the lenses free of ice and snow during the winter.
Some of the cameras might be domes capable of moving as fast as 200 degrees-per-second. Others might be fixed cameras with low-light lenses. Coaxial cable would carry video and audio signals connecting each camera to a processor that coordinates all communication between CCTV cameras, monitors, the VCR, and the multiplexer.
The fixed cameras would cover specific zones, while the PTZ devices would be programmed to watch the five busiest entrances during the morning and afternoon rush hours and to scan the grounds during off-peak times. The security team in the central control station could also manually operate the moving cameras with a control stick.
In addition, the PTZ cameras are integrated with an overall access control and security system, so doors with card readers or combination locks and entrances equipped with contact breakers signal the PTZ camera to focus on them when they open. When one of the doors opens with the contact breakers, a camera immediately zooms in on the door to record who's entering or exiting.
An alarm also signals in the control room to inform the security officer on duty that someone is using a door.
It all adds up to a total solution with pan/tilt/zoom just one part of the overall security system. There are lots of PTZ solutions available from longtime players such as Pelco, Panasonic, Telemetrics, Ultrak and Sony among others.
WIDE AREA SURVEILLANCE
Radar-Digital Systems is a video surveillance and PTZ manufacturer specializing in wide area video, radar and environmental monitoring systems for harbors, transportation and development sites via LAN and the Internet. The company's new PTZ technology uses the Internet and high-accuracy technology that measures pan and tilt angles to 0.01 degrees to know precisely where the lens is pointing at all times. "Every system we deliver (one of our rugged video cameras and one of our video controller servers) has a digital map included in a control-display Web page. Using Netscape 6.2 Web browser to access our software in the video controller server allows a user to merely click on the map and the camera goes to that point immediately. We even show a Web page with a line on the map of exactly where the camera is pointing," says Rick Fay, president of Radar-Digital Systems.
"Our market is oriented to wide area video surveillance: ports and harbors, highways, intersections, coastal areas (power plants) and such," he continues. "For example, the pointing accuracy of our camera is about 16-inches in a mile. This accuracy brings up a whole new set of video surveillance capabilities one can't get from traditional domes or CCTV cams on a pan-tilt head," Fay says.
"One other aspect of our new camera is its 12v DC supply, which allows us to have a solar-powered, battery-operated video camera system with a wireless video link of up to 20 miles. Cal Trans has bought some of these for trials with plans to use them at Lake Tahoe and in very rural locations," Fay concludes.
One of Radar Digital Systems' projects includes the Harbor Video Monitoring System for the Port District of Santa Cruz, Calif. A single pan/tilt/zoom video camera system, remotely mounted 750 feet away, sends video via twisted pair Cat-5 cable to a video control-server unit (VCU) which is connected to internal LAN to provide operator control and display via existing desktop computers on the private network. VCU is also connected directly to the Internet to automatically upload a set of live video images to a Web site.
Radar-Digital Systems has also installed a CCTV traffic monitoring system in the San Francisco Bay area for the California Department of Transportation which includes two dynamic PTZ video cameras and 12 fixed CCTV cameras with 12 video time-lapse recorders, all controlled by one VCU. The system provides control and display via wireless LAN to CalTrans Traffic Management Center in Oakland, Calif. The CalTrans system will eventually have 435 cameras strategically placed over the entire bay area freeway, many of them with pan/tilt/zoom capability.
COVERING MORE AREA EFFECTIVELY
There are a lot of choices in PTZ systems ¡ª the key is to decide how critical the technology will be to meet the goals of the overall security plan. It's always a good idea to obtain the services of an experienced CCTV design professional to determine camera placement, pathways, correct equipment selection, etc. Experts say the trend is toward using PTZ in conjunction with other security solutions like card access or property tagging. The biggest mistake most facilities and businesses make is not dedicating adequate resources and capital to keep the system operating at peak performance. From retailers to schools to government operations, today's pan/tilt/zoom technology offers affordable CCTV solutions that allow you to cover more area, more effectively.
A former editor of Government Video magazine and U.S. Navy photojournalist, Tom Patrick McAuliffe is a contributor to Access Control & Security Systems who also writes for Video Systems, a sister publication.