Go to the White Light

Video surveillance can be considerably improved by using LED lighting. The low-voltage, solid-state technology includes both infrared and white lighting capabilities, and the “green factor” of LED lighting’s low power consumption makes it financially feasible to establish lighting levels high enough to ensure quality images commensurate with camera capabilities.

A number of manufacturers make LED lighting specifically designed for use with security video cameras. Typically, the light design includes LED bulbs and lenses, and some have a hinged two-part light fixture design for narrow or wide beam adjustment, so that a field of light can be achieved that corresponds to the field of view of the camera.

Two visual advantages of white LED lighting over infrared lighting include color night video, and the fact that the eye of a patrolling officer or first responder will see just what the camera sees, whereas infrared lighting provides no visual benefit to observers in the field.

However, practitioners should not limit their consideration of LED lighting to pairing lights with cameras. There are considerable benefits and cost savings to considering the broader lighting picture.

 

Safety and Operational Benefits

In addition to video surveillance improvements, white LED can provide significant safety improvements and a higher comfort level for individuals who are on-property in late evening and nighttime hours.

Figure 1 illustrates the comparison of traditional lighting — a mixture of fluorescent and high-pressure sodium (HPS) lamps — and white LED lighting in a warehouse application. The parking lot areas in Figure 2 show the stark difference between traditional lighting and LED lighting. It behooves safety and security practitioners to take the entire spectrum of value into account and consider where current LED lighting technology, especially white lighting, can provide improved risk mitigation at a good cost.

A business case can be easily made for a transition to white LED lighting. Here’s an overview of the benefits, which will be explored in-depth as you read further:

  • Lower energy costs;
  • Low to practically no maintenance costs;
  • Life expectancy between 8 and 20 years;
  • Lower total cost of ownership;
  • Improved personal and/or operational safety;
  • Enhanced security deterrent effect;
  • Improved security video images;
  • Nighttime color video;
  • Reduced video network bandwidth;
  • Enhanced facility appearance;
  • Battery backup options;
  • Better compliance with lighting control ordinances; and
  • Potential contribution to LEED certification.

The stakeholder list for lighting improvement projects can include security, safety, finance, HR, legal, real estate/facility management, operations management, partners, customers, visitors and public relations. It is common to find that a lighting improvement project has ROI that spans multiple business functions.

 

Energy Savings and Cost Picture

It is common for wide-area lighting to insufficiently illuminate walkways and waiting areas to the degree desired, and for those areas not to get additional lighting treatment due to the total cost of traditional lighting. LED lighting has no “warm-up” period, and LED bulb life is not affected by cycling lighting on and off; thus, LEDs are perfect for motion-activated usage where more light is desirable only when people are present. Now, the existing lighting at walkways and waiting areas can be supplemented with motion-activated LED lighting, with no discernible impact to energy costs.

LED lighting fixtures typically have a higher purchase cost than traditional lighting fixtures — a major reason is that the quality of LED lighting is temperature-dependent, thus requiring a more advanced fixture design. This is offset by the fact that LED light bulbs have a much lower operating cost and longer life expectancy than other types of light bulbs.

Cost savings from lower energy use and elimination of traditional lighting maintenance typically provide a financial ROI of three to five years, with some case studies even showing a one-year return. Case study information is available from leading manufacturers.

Figure 3 illustrates the reduced Total Cost of Ownership picture for LED lighting fixtures compared to high intensity discharge lighting typically used for large area illumination.

 

Improving Visual Acuity

Visual acuity is the ability to discern details at a certain viewing distance. In general, the brighter and more even the lighting, the better the visual acuity is for a given observer. When there are light and dark spots in the area being viewed, visual acuity is diminished across the scene. Lighting uniformity and good scene color are factors that improve visual acuity and provide pedestrians with a more comfortable environment because they can see better than in traditionally lighted areas. This is also important, of course, for patrolling officers and first responders.

The lower TCO of LED lighting compared to traditional outdoor lighting and the variety of fixtures available make it feasible to design much more uniform area lighting and pathway lighting. The white light quality of LEDs also improves the color aspect of lighted areas.

 

Safety and Security Design Considerations

It has long been known that good lighting is an effective crime deterrent; thus, lighting is one element in CPTED (crime prevention through environmental design). Landscaping is part of the lighting picture, as trees, shrubs and other greenery can block light and create shadows and hiding places. In most cases, it is not desirable to simply eliminate such greenery; however, a combination of trimming and additional LED lighting can make potential nighttime hiding places very unattractive.

Small motion-activated LED lighting fixtures in such locations are a considerable deterrent — they provide a bright indicator light signaling when someone is present, and thus can deter unwanted or prohibited behavior that would otherwise go unnoticed.

Many models of outdoor LED fixtures and LED lighting intended for video surveillance applications incorporate a light sensor element and have inputs enabling motion-activated or scheduled control.

 

Lighting Ordinances

There are many factors prompting the growing adoption of lighting ordinances, the primary one being public safety. LED lighting makes it easier to comply with these ordinances because LED is more highly directional than traditional lighting, and because the fixtures are designed for compliance to common ordinance requirements.

A good general summary of the concepts and implementation of municipal lighting regulation is the Outdoor Lighting Code Handbook published by the International Dark-sky Association (IDA) in 2000 and revised in 2002 (www.darkskysociety.org/handouts/idacodehandbook.pdf). More recently, the Illuminating Engineering Society of North America (IESNA) and the IDA collaborated to produce the Model Lighting Ordinance (MLO), which was released in mid-2011. (www.darksky.org/outdoorlighting/mlo.)

The MLO offers several innovations to outdoor lighting regulation, including the use of five lighting zones to classify land use, with appropriate lighting levels for each. Other innovations limit the amount of light used for each property and regulate the amount of uplight (skyward-directed lighting) for street lighting.

 

Video Network Bandwidth Reduction

Of particular importance to both security departments and IT security, LED lighting can reduce the bandwidth requirements of video streams from low-light areas. 

Nighttime video from outdoor network cameras and network-encoded analog cameras have a lower compression rate than daytime video from the same cameras. The same is true for cameras in indoor areas that have a lower level of lighting after hours. In order to improve the low light image, cameras amplify the video signal—which has the effect of amplifying the electronic noise (which appears in the video image as randomly changing patterns of tiny dots). The amplification factor, called gain, is the extent to which the amplifier boosts the signal.

Most network cameras default to automatic gain control (AGC), and have circuitry that works to optimize the visual image. In very low light conditions, a camera’s ACG circuitry can boost the signal up to 100 times its original level. That would mean 100 times the level of noise in the image.

Even though the visual impact of the video noise is secondary and the main aspects of the target scene can still be seen by a human viewer, to the compression algorithm the noise constitutes tiny details in the image that are continuously changing — thus, compression techniques such as those used by H.264 video encoding are able to provide only slight compression.

A scene evenly-lit even by low levels of LED lighting can result in bandwidth reductions from 20 to 40 percent, according to field tests.

 

Optimizing LED for Surveillance

LED light from even small fixtures can be more intense than other types of lighting, especially when close to the lighting source — causing light-colored objects to wash out or creating flaring white spots in the video. This can occur with both with infrared and white LEDs. Close proximity to the source of light can result in washed-out facial images or vehicle license plates (which are highly reflective).

LED Lighting intended to support a specific camera should be adjusted by location, light focus, light width adjustment or a combination to match the camera’s field of view (FoV). The objective is to reduce lighting hot spots within the image. Field tests are appropriate — what has been found to work at initial LED test sites should be documented to provide design guidelines for the remaining sites selected for lighting improvement.

Before finalizing the exact position of lighting fixtures, such as at pedestrian or vehicle entryways, designers should perform field tests to determine: the maximum level of lighting that can be used without causing flare spots or wash-out; and the minimum level of lighting required to achieve an acceptable low-light video image with minimal noise.

Setting these levels as minimum and maximum standards of lighting for specific area types and activity levels can provide effective guidance for lighting device selection and placement.

 

Proving Ground

A highly publicized case study is that of the Newport News Public Schools (NPSS), a school district in Newport News, Va., which in 2008 updated the campus lighting of its seven schools with LED lighting, achieving a 65-percent reduction in annual lighting energy costs.

Here are a few of the calculated savings from the seven-school project, which replaced 189 parking lot high-pressure sodium fixtures and 150 exterior building illumination incandescent fixtures with white LED lighting:

  • Annual energy savings: 139,000 kWh
  • Annual energy cost savings: $10,463
  • Annual energy costs reduction: 65 percent
  • Payback time: Three years

It becomes plain that the benefits of deploying LED lighting goes beyond simply improving the quality of video surveillance images. While the benefits of security video improvement may not be enough to make the business case, the other benefits — especially the cost-savings — can tip the scales in favor of project approval. And as LED lighting technology continues to improve, and as the cost of energy increases, the ROI from LED lighting will become even higher.

 

Ray Bernard, PSP, CHS-III is the principal consultant for Ray Bernard Consulting Services (RBCS), a firm that provides security consulting services for public and private facilities. For more information about Ray Bernard and RBCS go to www.go-rbcs.com or call 949-831-6788.

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