August 1992, Hurricane Andrew slammed the Florida coast and wiped out thousands of homes. According to local security advisors, the 175-mph wind and driving rain also destroyed nearly every outdoor surveillance camera.
Today, security consultants are demanding that sensitive security locations have CCTV systems that can withstand and operate in the 155-mph winds of Category-5 hurricanes. Outdoor CCTV systems are now expected to survive the harshest of conditions from destructive hurricanes to brutal vandal attacks. However, achieving effective security in Mother Nature's environment is not always accomplished by most CCTV installations. There are too many cases where cameras, rendered inoperable by environmental damage, have failed to deliver the irrefutable evidence required for an investigative breakthrough or conviction.
For example, two people were shot in a June 2006 drive-by shooting in Trenton , N.J. Although there were surveillance cameras situated at the crime scene, they failed to capture the incident. Technical shortcomings, including inability to capture clear images at night, foggy lenses and housings filled with water, are being blamed for the failure of Trenton 's security cameras to deliver images that could help deter or solve crimes.
Unfortunately, in countless cases across the nation, outdoor environments defeat cameras, rendering them useless and frustrating authorities who rely on them. Security cameras today are expected to operate reliably and to specification in their respective environments, regardless of how difficult those environments may be.
Effective, reliable security systems are the foundation to a security professional's long-term business success. Security professionals can help ensure their outdoor CCTV installations work effectively by considering the main environmental culprits that defeat outdoor cameras.
Weather Can Wreck Havoc Due to Temperatures, Water, Dust, Wind
One of the most common problems for outdoor security applications is the weather. Heat, cold, water, dust and wind are all common factors that degrade outdoor security equipment day in and day out.
Well-designed security equipment anticipates the problems of the outdoor environment. For example, heat can have damaging effects on the sensitive electronics commonly found in today's security equipment, causing premature degradation and potentially melting the electronic subcomponents.
Superior thermal management design is evident when devices run cool and do not use a lot of input power as compared to its output. The best designs do not require intake air and cooling fans. These practices, although critical, are not always followed. Some infrared illuminators, for example, run hot, take in air and are overdrawn to produce a greater output, which results in a shorter product life.
In contrast, cold environments can lock up electronics and restrict the motion of any mechanical components such as day-night filters, auto-irises and zoom lenses. Materials such as rubber or plastic may become cracked and brittle under extremely cold temperatures, eventually requiring replacement. Surveillance equipment typically incorporates onboard heaters, insulated all-weather housings or both to help protect from cold.
All-weather housings are often environmentally sealed to prevent the entry of water, dust, insects and other foreign particles that may interfere with the equipment's function. In general, an environmentally sealed housing is preferable to an air-cooled housing equipped with a fan, which often results in dirty filters requiring periodic replacement. Additionally, all-weather equipment is typically designed to be well-insulated against the elements, eliminating the risk of frost or condensation on the electronics.
Condensation and water ingress due to torrential rain or heavy snowfall often cause surveillance cameras to malfunction. Too many security professionals have the unfortunate experience of finding their cameras filled with water and their electronics submersed, posing a shock hazard. An environmentally sealed, all-weather housing provides total protection against harsh weather conditions and is usually considered a requirement for environments exposed to wet conditions.
Given the importance of choosing a camera that will meet the demands of its environment, one of the most important tools available to security dealers is environmental standards. In the security industry, the most commonly specified environmental standards are NEMA 4, NEMA 4X and various IP ratings such as IP68, generally considered the highest environmental standard. Security professionals who require performance under challenging environmental conditions should select products that comply with the appropriate standard.
Vandalism Protection Calls for Tough, Hard-to-Grab Housings
Installation in an outdoor environment often leaves CCTV equipment vulnerable to acts of vandalism. Cameras are often attacked using rocks, bricks, bats and gunfire. As such, surveillance equipment charged with monitoring vandal-prone areas must be able to provide continuous video vigilance in physically abusive environments.
One of the simplest steps to take is installing the camera at a height that is beyond reach. A height of 12 feet or higher will significantly reduce the number of attempts at a vandal attack.
In order to protect against rocks and other projectiles, cameras destined for vandal-prone areas must be constructed of exceptionally durable materials such as solid billet aluminum or heavy-gauge steel. These materials provide outstanding mechanical strength to preserve the structural integrity of the enclosure and to ensure internal camera components are protected. Ballistic inserts, such as LEXAN, are also available to ensure the optical window remains intact in the face of gunfire.
Ballistic inserts must be able to resist the tremendous impact, momentum and shock generated by bullets. For example, ballistic-rated UL752 level-6 construction protects from gunfire, preserving the camera's internal components for uninterrupted video surveillance.
When it is necessary to position cameras at low heights (in order to capture clear facial images, for example), physical shape and design are crucially important factors. The most common problem of low-mounted cameras is that they are forcibly ripped or rammed off the wall to which they are attached.
Some cameras are designed so they are difficult to grip. Extreme CCTV of Burnaby, British Columbia, Canada, offers cameras incorporating a No-Grip™ design that reduce the risk of being dislodged. The design, which features a polycarbonate dome and anodized aluminum housing, also eliminates all anchor points so ropes, belts or wires cannot be tied around the camera body.
Another vulnerability in outdoor CCTV installations is exposed cabling, which vandals can easily rip or cut away. In order to reduce the risk of cabling damage, security professionals can specify cable-managed cameras and brackets that do not expose any wiring.
Thermal Imaging, Active-Infrared Provide Images in Dark Conditions
Dark conditions pose numerous challenges to upholding safety and security. For one, darkness leaves outdoor areas more susceptible to unlawful acts. In fact, a large number of crimes occur at night when offenders believe they cannot be seen. Darkness also affects the image quality produced by standard CCTV cameras.
At the most basic level, cameras need light to make pictures. In environments where there is very little or no light, conventional cameras deliver poor-quality surveillance video, resulting in compromised site security. In order for outdoor CCTV equipment to provide effective, around-the-clock surveillance, it must be able to deliver clear images even in low-light and zero-light conditions.
Thermal imaging and active-infrared night vision play a significant role in enabling surveillance in low visibility conditions. Although the two technologies function very differently, they both allow CCTV cameras to capture clear images in the dark. Thermal imaging creates a picture by detecting heat differentials between objects; it does not require any light to produce an image.
A security camera using thermal imaging displays the temperature variations as shades of gray with warmer areas appearing light and cooler areas appearing dark. In this capacity, thermal imaging is highly effective for detection and classification level surveillance.
In contrast, active-infrared night vision does not rely on heat differentials to produce an image. Instead, active-infrared systems project infrared illumination onto a scene, using the light reflected back from the scene to generate video images. Active-infrared night vision can eliminate shadows from a scene, resulting in an evenly exposed picture.
Images formed using active-infrared also generally have a higher resolution, allowing for greater picture detail. This capability makes active-infrared night vision suitable for recognition and identification level surveillance.
In turning darkness into day for surveillance cameras, security professionals must also ensure that their efforts do not impact the environment negatively. Wide-area floodlighting, a common security practice used to deter criminal activity from susceptible outdoor areas, has been identified as a major contributor to light pollution.
In addition to allowing CCTV cameras to capture clear images in dark conditions, thermal imaging and active-infrared offer an alternative to using floodlighting to implement security in outdoor premises. Invisible to the human eye, thermal imaging and active-infrared do not cause light pollution. Both technologies can also “see” through exceptionally far distances; this ability reduces the number of devices needed to cover an area, minimizing power consumption and, thus, the negative effects to the environment.
Optimizing Video Analytics and Megapixel Surveillance
Active-infrared night vision enables the optimized performance of video analytics in low-light and zero-light conditions. Video analytics requires an evenly illuminated, high-signal, low-noise picture to function and properly detect potential threats. Otherwise, poorly lit, noisy images wreak havoc on video analytics software, triggering false alarms and rendering the software ineffective.
By evenly illuminating a scene, active-infrared improves the picture dramatically and produces high-resolution, high-fidelity images. These images serve as usable data, allowing video analytics to work as intended.
Active-infrared also provides benefits for megapixel surveillance, which is often specified for high-level security projects. Although megapixel cameras produce high resolution and wide fields of view, they still have the same light requirements as traditional CCTV cameras. Active-infrared helps megapixel cameras provide effective nighttime surveillance.
Special Considerations Include Especially Harsh Environments
It is clear that the range of potential outdoor environments is very broad. There will be projects where special consideration is required to meet special environmental factors.
Chemical factories will require PVC cameras to protect from harsh chemicals. Underwater applications require submersible cameras capable of operation under pressure. Desert environments require specially designed cameras that will operate in very hot temperatures. Hazardous locations such as petrochemical sites require certified Class I, Division 1 cameras for explosion-protected performance. In addition, security professionals must also consider whether to use fixed cameras, which are best for uninterrupted surveillance of critical areas, or pan/tilt/zoom cameras, which are best suited for wide-area monitoring. Furthermore, today's integrated security installations often incorporate solar-powered digital wireless components for locations where hard-wiring is either cost-prohibitive or simply not an option.
Adrian Tse is the director of communications for Burnaby, British Columbia, Canada-based Extreme CCTV Inc. Tse can be reached via E-mail at atse@extremecctv.com .
An Analysis of Analytics
By Nikhil Gagvani, Ph.D.
Intelligent video (also known as video analytics) is a software application that analyzes video data from security cameras to identify specific events of interest and issue visual, audio or text alerts to designated personnel. This capability is commercially offered as a standalone software application or embedded in hardware platforms such as processors, encoders and cameras.
For outdoor systems, understanding how different video analytics products deal with illumination and environmental effects is critical. Knowing how advanced analytics product offerings perform under real-world conditions can help industry professionals better understand how to apply this potent new capability with the security objectives of customers.
Illumination — Outdoors, there are many visual changes that are generated as a result of modifications in illumination. Often they are not in and of themselves actual physical objects that pose a security risk, yet they generate visual changes that can be misreported by video analytics applications. Some common examples include images created by automotive headlights, glare and reflection of light bouncing off mirrors and windows. If a video analytics product reports every change without distinction, then it becomes truly ineffective.
Sufficient lighting for effective video surveillance during evening hours or low light situations is a frequent challenge that's usually addressed with infrared cameras. Yet infrared video streams provide little or no color distinction. Video analytics products that analyze based on color can be limited in such situations and better suited to indoor environments or daytime surveillance. The most robust video analytics products address both illumination and color issues by applying advanced image processing algorithms that distinguish native motion and visual artifacts from real objects. These capabilities combine to ensure the system generates only relevant alerts for investigation by security personnel.
Environmental clutter — This is another relevant influencer to the application of advanced analytics in outdoor environments. As IMS Research has so aptly stated, “ … [intelligent video] is based on analyzing changes in the pixels of video frames captured by CCTV cameras but generally does not account for environmental changes such as rain, lighting, shadows and even plant growth.”
As discussed, the movement of wind, leaves or animals induces changes that might be identified by video analytics applications as events of interest but, in reality, are not true security threats. Masking particular, nonthreatening yet common movement is a smart course of action, but not a catchall solution.
To further complicate matters, dynamic outdoor environments might find that lurking behind the moving branches of trees are suspicious people with the immediate intent to commit a crime. If the trees are thoroughly masked, the video analytics solution won't be able to pick up the intruder or alert security personnel before the criminal commits a crime. Then again, if the trees are not masked at all, the application might not detect the motion of the intruder as a potential concern.
In order to create a resolution for the innate outdoor movement challenges that impact the success rate of video analytics products, the solutions must operate without masking regions of repetitious motion yet be able to identify and analyze sections of distinct or new movement.
Effectiveness — Advanced analytics capabilities are a vital function of video surveillance systems, especially large installations with many security cameras. Bearing the impact of outdoor illumination and environmental clutter conditions in mind, security professionals and advisors may wonder how effective a product's analytic capabilities might be.
The best solutions will effectively operate in outdoor environments ‘out of the box' with little engineering or ‘tuning' required. These solutions typically avoid the proliferation of alerts for every potential motion or lighting issue, thereby alleviating many of the “if, then” indicators brought on by outdoor light and movement challenges. Out-of-the-box solutions also provide the ability to effectively monitor a large outdoor area at a lower cost, while concurrently requiring fewer modifications and amendments to system preferences after they've been defined. Or, if necessary, provide simple ‘point-and-click' functionality that allows system administrators to complete changes to large numbers of cameras quickly, easily and without the need for a complete system shut down.
These influencers are just two key factors for consideration when implementing video analytics in outdoor video surveillance systems. According to a survey published by the ASIS Foundation, 32 percent of security services companies indicated they provide outdoor perimeter protection, certainly proof of the importance for integrators to understand the relevance of intelligent video analysis in outdoor deployment.
Nikhil Gagvani is the chief technology officer and vice president of engineering for Reston, Va.-based Cernium Corp. ( www.cernium.com ).