Perfecting Detecting

December 31, 2007 SSI Staff

Intrusion detection has come a long way since the days of trip-wire activated burglar alarms. Sensors are now “smarter” and can accurately recognize threats while avoiding changes in the environment and minimizing false alarms. With cities throughout the United States opting to incorporate verified response legislation, accuracy of intrusion sensors is paramount. New wireless designs, mesh capabilities and convergence with other technologies, has created an intrusion sensor that is far more reliable.

By combining video motion detection with recent intrusion sensor technologies, opportunities are arising for installers to reach new, existing and retrofitted CCTV accounts and alarm installations. As a result, integration into other systems will become more prevalent as sensor technologies continue to advance.

Combining Sensor Technologies to Prevent False Alarms

Since the development of the passive infrared (PIR) sensor in the 1980s, sensors have undergone a technological transformation. Advancements in sensitivity and adaptability have created different forms of intrusion detection sensors, all of which guard against the all-too-common occurrence of false alarms. PIRs often cause alarms during unthreatening events such as the wind blowing, a car’s headlights or even radio frequency (RF) interference.

“False alarms can also come from internal noise within the electronic circuits of the sensor itself,” says Larry Tracy, president and CEO of Reno, Nev.-based Aleph America. “Every sensor manufacturer has its own techniques to deal with these issues.”

To combat false alarms, companies such as Bosch Security Systems of Fairport, N.Y., have combined several sensors to create what Bosch calls Sensor Data Fusion technology. Bosch is able to produce this technology by incorporating long-range PIRs, short-range PIRs, microwave, white light and temperature sensors into one intrusion detector.

While the concept of incorporating several sensors into one detector is not new, Bosch analyzes the data in an innovative way. The detector is able to balance the sensors and adjust sensitivities by collecting the information and then feeding it into a microprocessor where it can then be analyzed by a complex algorithm. This enables the detector to make an intelligent decision, indicating whether a certain condition is indeed a valid alarm.

“Progress in microprocessor technology has allowed manufacturers to significantly increase the performance of motion detectors,” says Tom Mechler, Bosch product marketing manager. “Our detectors now incorporate analog data from up to five different sensors to make an alarm decision. This provides better catch performance and false alarm immunity than ever before.”

The ability for sensors to read environmental conditions and adjust to surroundings is vital in preventing false alarms. Adaptive sensors are able to adjust their sensitivity modes, recognize a threat and adjust their sensitivity, accordingly. The sensor’s dependability is increased without ever compromising its catch sensitivity.

NAPCO Security Systems of Amityville, N.Y., has patented its Adaptive® Dual Microwave/PIR detectors for false alarm immunity. The unit’s microprocessor software has algorithms for analyzing signatures of false and valid alarm sources, defined by size, amplitude, sequence and characteristics, according to Judy Jones, NAPCO’s vice president of marketing. The sensor is able to assess a signal from a target and instantaneously determine if it is nonthreatening, such as an animal or the wind, or if it is an intruder.

The Adaptive detector automatically selects the most appropriate detection mode when it is faced with hostility or tranquility. This allows the detector to optimize both intruder catch and stability. The sensor will generate a signal when a stimulus is strong; however, if the signal is not strong enough to sound the alarm, the sensitivity modes will automatically change. The adaptive technology widens the gap between the detected signal and its alarm threshold, Jones says. By using smart sensors that can automatically adjust sensitivity, the performance of conventional dual-technology devices increases and the threat of false alarms is dramatically reduced.

“We have also made a breakthrough on reducing the number of components through creative use of new microcontrollers just introduced to the market. We are seeing component reductions of over 70 percent compared to earlier models,” says Tracy. “Fewer parts means more reliability, which leads to fewer sensor failures and, thus, fewer false alarms.”

In addition to component reductions, Aleph has also developed a patented sensor that allows mounting heights of up to 33 feet, with a 100-foot radius. “This sensor is physically smaller than its closest competitors and has four separate sensors within one housing to minimize false alarms and increase detection sensitivity,” Tracy says. “The other advantage is, unlike other detectors, each one of the four segments can be individually turned off to prevent false alarms in an area you don’t wish to detect in.”

Setting the Standard for Intrusion Sensor Accountability

Detection devices must undergo rigorous testing to ensure sensors meet requirements and actively prevent false alarms. Tane Alarm Products of New Hyde Park, N.Y., manufacturers metal contacts that trigger the alarm system when a door or window is breached. While the metal contacts are small, they play a large role in an overall intrusion detection system and must follow anti-false alarm testing as well.

“Metal contacts are the first line of defense,” says Tab Hauser, president of Tane. “We have induced a no false alarm policy by using reed switches and double testing.”

Hauser says his company tests all metal contacts twice before they are put on the shelf to make sure they are working properly. The company’s Web site states that its contacts have been tested to operate over 400 million cycles, yet the contact can be unused for years and still work properly at that one critical time.

Aleph’s products undergo both field testing and independent laboratory (UL) testing before being released on the market.

“Products are designed to meet UL 639 or EN standards [European standards],” Tracy says. “As a second function, we use the standard red walk test LED in reverse as a light sensor to detect white light events. Another novel approach is to use the same red LED to detect incoming RFI and, again, using special algorithms we are able to ignore the false alarms. Both of these techniques are allowing our new sensor line to exceed standards required by test agencies by over 10 times.”

Wireless Aims to Match Hardwired False Alarm Immunity

With the popularity of wireless and hybrid security systems, the need for wireless intrusion sensors is increasing. While many manufacturers have not yet taken the step toward wireless intrusion detectors, companies such as NAPCO are moving forward and developing wireless designs that promise the same false alarm immunity as hardwired intrusion detectors.

“The most significant development in wireless design is the advent of two-way wireless networks,” says Mechler.

The design provides higher security because the device reads the signal and transmits as necessary, reducing on-air time. The system will only retransmit messages when needed, as opposed to one-way wireless designs that transmit multiple signals for each message.

“It provides intelligent power management, allowing detectors to
sleep during disarmed periods, greatly increasing battery life,” Mechler says. “It provides control capability for outputs and sounders, giving the end user more functionality.”

Sensors and Video Cameras Converge for Verification

While the video motion detection market continues to grow, intrusion sensors are evolving, allowing for the integration with video to improve.

“Video motion detectors are becoming more prevalent and are becoming the motion detector of choice when systems already include video. The advent of video content analysis allows for higher security and the cost is improving, allowing the technology to be deployed in a wider variety of applications,” Mechler says.

In following the trends of the convergence world, NAPCO has developed pixel-based video motion detection that converges traditional intrusion sensors with motion detection called Isee Video.

“[We] have just introduced new technology in our online video gateway product that basically transforms any brand of conventional video surveillance cameras into motion detectors, providing both precise pixel-based video motion detection and video verification simultaneously,” Jones says.

Following suit, Aleph has recently introduced a line of sensors with built-in cameras for video verification. “The cameras field of view overlaps the sensors’ coverage. A unique circuit allows the video signal to be superimposed upon the standard alarm loop. No ‘new’ wire needs to be run by the installer to add video to an existing installation where sensors are currently installed,” Tracy says.

New Capabilities Offer Labor Savings and Recurring Revenue

The new anti-false alarm technologies and integration with video motion detection has proven to be beneficial all around. The adaptability and accuracy of sensors is impacting manufacturers and installers in a positive way by providing end users will a reliable product.

“End users can now enjoy better detection, higher reliability and fewer false alarms than ever before,” says Mechler. “For those systems that will already include video, end users can now add more intrusion detection through the use of video motion detection, providing them with more security choices, higher integration and a lower overall system cost.”

Jones says the economical implementation will represent an incremental recurring revenue opportunity for security professionals on new alarm and CCTV installations as well as existing and retrofitted CCTV accounts and alarm installations.

“This new video capability complements the professional alarm company’s offering beyond mere alarm systems, providing convenience and peace-of-mind to an increasingly PC-centric and busy consumer who strives virtually to be two places at once,” Jones says.

In addition, Jones says microprocessor-controlled PIRs are the answer for the increasing need for easier-to-install PIR detectors and will ultimately result in labor savings for installation companies.

Mechler says there will always be a place for standard motion detectors because of the favorable performance to cost ratio; however, when video is already part of a security system, video motion detection will replace standard motion detectors in many applications. As sensors continue to advance, integration into other systems such as energy management will become more prevalent over time.

Because false alarms are now avoided from the get-go, security companies will be able to save service costs and damaged reputations, while end users will avoid false alarm fines and prevent the unnecessary use of response resources.

“Future designs will get much more intelligent to the point where we will reach the ultimate goal of faster catch performance and detect only human beings,” Tracy says.

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