Low-Light Surveillance Advancements Ready to Shine on Burglars and Beyond
See how security dealers can capitalize on today’s cameras, plus when to deploy thermal varieties.
THE NEED FOR crisp, clear, discernible video images in low-light applications has always been present. Burglars have long conducted their fair share of illegal activities under the cover of darkness. And now that society is faced with terrorist threats seemingly around every corner, the demand for quality video documentation after dark has never been as great as it is today. In many instances this need is immediate where the risks are high and detection imperative in real-time.
A good example of where quality, real-time video is necessary, both day and night, is on the border between the United States and Mexico where drug cartels operate, attempting to smuggle drugs into the U.S. and small arms into Mexico. Now there’s also a potential of infiltration of ISIS operatives who intend to commit acts of atrocity on U.S. soil. In this geo-political setting, mission-critical detection must occur in near total darkness.
The stark reality with regard to low-light video surveillance is that the technology has not always been capable of producing clear, concise images after dark, at least without a workaround of some kind.
“You can add more light to the scene, and IR [infrared] is one way to do that. Another way is to use something other than visible light, which thermal technology does. Of course, each one has its pros and cons as well as price tag,” says Sean Murphy, North American market director for video security products with Bosch.
Besides IR illumination, other workarounds include the addition of visible light in the vicinity of the field of view, which increases the amount of reflective light that reaches the camera imager. The most common ones include the use of visible wall and pole lights, especially when LED lighting is available and the job supports the added cost. Other workarounds include the use of video intensifiers, low-light lenses, thermal cameras and an armada of sophisticated software within the camera – all of which seek to turn dark spaces into visible ones.
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Manufacturers also have created true day/night cameras where the IR cut filter is mechanically removed after dark, in addition to adding IR illuminators when the light level is low enough to require it. Both act to increase the amount of usable, available reflected light. And where the light level drops below a given level, all remnants of color are removed through signal processing to create crisp, clean black-and-white (B/W) pictures, free of noise as well as other anomalies, all of which can take away from the user’s ability to identify a perpetrator. Let’s take a closer look at the attempts to improve low-light imagery and the important features security providers need to consider for design and installation, including the potential deployment of thermal cameras.
New Sensor Technology ‘Sees’ Better
For many years IP megapixel (MP) cameras earned a reputation as poor performers in low-light situations. One remedy for some manufacturers has been to combine a daylight color camera and a low-light B/W camera in the same frame. These cameras visibly contain two lenses, one for day use and the other for after-dark applications. In this instance both camera elements integrate together so the user continues to receive usable video images no matter what the circumstances may be. This method of providing 24/7 coverage will continue as a viable means of surveillance for some time to come.
One reason why megapixel imagers have historically experienced problems performing in low-light settings is the fact that the pixels are so small. Only a minimal amount of light can reach them for the purpose of creating usable images. However, because of improvements in CMOS (complementary metal oxide silicon) imager and optical-lens technologies, this situation is quickly changing.
“At Bosch, we [have our] Starlight technology, where we use [improvements in] sensor technology along with special algorithms to enhance the image so the camera can ‘see’ with less light than normal,” says Bosch’s Murphy.
According to Adimec, a designer and manufacturer of high-performance industrial cameras for equipment manufacturers in machine vision, health care and global security: “Previously, CCD [charge-coupled device] image sensors offered sensitivity advantages, especially in higher temperatures. CMOS image sensors used to require additional functionality or even cooling to achieve the same noise performance and image uniformity at higher temperatures. Now that CMOS image sensors have caught up or even surpassed in performance, it makes sense that almost 75% of industrial cameras are expected to be using CMOS image sensors by 2016 [according to a market survey from Framos]. The changeover is happening rapidly, even in applications with challenging lighting conditions such as in defense and other global security systems.”
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