The Lowdown on Low Light

Network video technology for dusk-to-dawn surveillance

Where they work well: Being able to detect heat and “see” into the shadows makes thermal cameras a fit for neighborhoods concerned about light pollution. They are also perfect for surveillance of perimeters — such as waterfronts, remote power plants and tunnels and railway tracks — because their enhanced detection capabilities help security staff quickly spot intruders or people in danger and thus reduce the risk of crime, accidents and fatalities.

Where they fall short: Thermal cameras do not provide forensic or facial detail, which makes identification impossible. Mist, dust, haze, snow and rain can block heat signatures, making detection more difficult from great distances. Some materials such as concrete, marble and asphalt reflect ghost images, while others like glass can block the thermal camera altogether. Like day/night cameras, thermal cameras do not show real-world color in the scene — the images are black-and-white or in a thermal color palette, as in the photo on the previous page.


Color in the Dark: Lightfinder

While some movie buffs yearn for the elegance of black-and-white movies, the surveillance world — like the world of cinematography — realized that color adds a rich dimension of realism to a scene and it is no longer satisfied with monochromatic night vision. Camera manufacturers have responded with a new technology that revolutionizes low-light sensors and low-light lenses.

Aptly called Lightfinder, the technology works in concert with a network camera’s lens, sensor and advanced image processor to sense the light intensity of the scene and then leverage heavy processing inside the camera to produce the best image. This results in lifelike color and detailed video at night and in full sunlight.

The quantum leap in visual acuity amazes first-time viewers. Note the above screenshot photos. No artificial light, IR illumination or video trickery was used to create these images. In fact, the scene was close to pitch-black at 11 p.m.; yet, in the right-hand image you can see the person in an orange jacket clear as day. Maybe he is part of the repair crew making regular rounds, or maybe he is looking to inflict damage on a critical switch. Visual details like this can confirm his identity or trigger a security alert.

Where they work well: Lightfinder cameras fit into that surveillance niche where users need to capture true color and other forensic detail when there is minimal or nearly non-existent illumination. For instance, this IP technology can reveal the identity of ships approaching the port. It can help transit authorities monitor underground tunnels and long stretches of track across remote terrain. And thieves looking for easy pickings at unmanned construction sites in the dead of night will be captured in vivid detail.

Where they fall short: A Lightfinder-enabled camera is not meant for complete darkness like a thermal camera, and when the environment drops below a certain lux level (0.05), it will switch to black-and-white mode like a traditional day/night (IR-cut filter) camera. So while it does stream video in color at extremely low light levels — which of course provides security practitioners with a new edge for identification — your surveillance environment might best be served by combining a variety of “night eye technologies” to ensure full coverage.


Eliminating the Advantage of Darkness

Security professionals now have a full range of network cameras to capture images in low and no light. Users can choose surveillance cameras that can detect, observe and report events across the visual spectrum with as much forensic detail as needed.

Where privacy is an issue, thermal cameras can distinguish heat signatures while preserving anonymity because they do not reveal details like facial features. At the same time, they can differentiate between a fallen limb and a person, which would help users better identify false alarms. Should a threat be deemed real, Lightfinder cameras can kick into action, revealing critical details and forensic clues necessary to an investigation.

Surveillance tools, especially IP cameras, represent a constantly evolving technology. Manufacturers continue to invest in developing smarter, more nocturnally acute cameras to push back against the criminal element intent on mischief under a cover of darkness. While it is amazing to consider how far we have come, it is even more exciting to consider what well-funded R&D teams will come up with next to make the lives of lowlifes in low light even more miserable.