Day/Night Surveillance Cameras Pull Double Duty
Even under extremely difficult lighting conditions, day/night cameras achieve optimal image results, making them a popular choice for surveillance.
It’s like day and night. Except these cameras are both. Since their introduction, day/night cameras have become ubiquitous, especially for outdoor use.
As compared to low-light cameras and cameras with packaged or external IR illumination, day/night cameras, through a mechanical means, capture color images when there is enough sunlight, and monochrome photos in total darkness or minimum illumination.
“True” day/night cameras work by implementing a physical infrared filter (movable IR cut filter to be exact) that is moved by a small motor. When the camera enters day mode, the filter is placed in front of the camera element, filtering the infrared and providing a color image. When the camera enters night mode, the motor moves the infrared filter out of the way for black and white night vision images. True day/night cameras often are a little more costly than some regular day/night counterparts and could be a lot more costly than certain other technology.
A Total Package
Day/night cameras and the various levels of image processing are part of a total package, of course. However, even the best day/night camera faces trouble if fitted with a poor quality lens, or if there simply isn’t enough light to generate a video signal.
Among other approaches, one is image enhancement which works by collecting the tiny amounts of light, including the lower portion of the infrared light spectrum and amplifying them to the point that the images are observable. Another is thermal imaging which operates by capturing the upper portion of the infrared light spectrum, which is emitted as heat by objects instead of simply reflected as light. Hotter objects, such as warm bodies, emit more of this light than cooler objects like trees or buildings. There also are different types of IR illumination devices including LED light, laser type and filtered incandescent lamps.
Some day/night style cameras are more capable than others. For instance, some capture color in low light with intensifier technology, monochrome without IR LEDs in low light and monochrome with adaptive IRs in almost complete darkness. Some cameras can be customized to the environment, such as light threshold and IR intensity with a built-in heater and anti-fog glass to reduce condensation in almost any weather condition.
Part of a Retrofit
Guy Grace at the Littleton Public Schools in Westminster, Colorado, is in the midst of a major “retrofit” project. But when it comes to types of cameras, he says that, within the retrofit, his day/night cameras now come with analytics. Check elsewhere in this issue for more details on Grace’s ongoing retrofit.
Night time applications obviously, are at the heart of day/night cameras, says Jeremy Buschine, director of IT service and repair at retailer ClickAway, with 41 brick and mortar stores in north central California. Such technology is “perfect for specific applications” but can be in lots of locations thanks to the latest day/night capabilities and lowering cost. Often day/night cameras can install right out of the box, and those without an internal IR filter can come with an illumination ring.
Buschine says he “takes great pride in the industry’s knowledge of technology. “And we do a lot of testing ourselves.”
Complexing nighttime challenges, there also are locations with particular needs.
For example, in the less populated northern regions of Saskatchewan, integrator Brigadier Security Systems installed a number of outdoor security solutions, including cameras, fencing and a day/night package of a camera, illumination, runs on batteries and sends video alarms over a cellular network from Videofied.
Overall, day/night cameras are not always perfect: limited visibility due to illumination problems or environmental factors, as well as vibration and background noise are some. Low-light cameras or thermal cameras can help with this, and there are also integrated optic and thermal cameras, which can give users the best of both worlds. Low-light and day/night also can go megapixel. For example, a bullet camera from Hikvision uses ultra-low light technology capturing color images in dimly lit environments, with true day/night, motorized zoom/focus, and IR up to 150 feet.
In the less populated northern regions of Saskatchewan, for example, cameras must also be must be rugged.
Despite the challenges, Brigadier Security Systems, a security integrator, has been successful with a number of outdoor security solutions, including cameras, fencing and wireless Videofied products and monitoring solutions.
Day/night can also play a role when planning to upgrade a video surveillance system from analog to IP. The Sunset Plaza Hotel of Hollywood, California, needed something that allowed for a lot of coverage in various environments around the premises, cameras that could supply high-quality images, and an interface that was easy to learn use.
“Before we weren’t able to clearly see what was happening, but now the images are very good at night and during the day,” says Brenda Elias, operations manager for the Sunset Plaza.
The Memphis Police Department (MPD) aimed at surveillance cameras on public utility poles, the elevated height of which would give the police a wide field of view with the capability of zooming in on critical details. Aside from wide dynamic range that extends the light range that cameras can capture, the approach also offers line crossing and intrusion detection which sends alerts to the police when someone enters or leaves a designated area. Each pole camera unit contains anywhere from one to three cameras, one of which is typically a network PTZ camera that has an 80-meter infrared range and 128 dB wide dynamic range for true day/night coverage.
One unique aspect: MPD has a gunshot detection feature that works in tandem with the PTZ cameras. A circuit board is programmed to listen for gunshots and essentially filters out all other noise. Microphones atop the enclosure pick up any possible gunshot sounds, and if those sounds are heard, the detector triangulates the location of the shot. It then guides the camera to pan, tilt and zoom in the direction of the gunshot within seconds.
Each pole camera unit actually contains anywhere from one to three cameras, one of which is typically a network PTZ camera that boasts an 80-meter infrared range and 128 dB wide dynamic range for true day-and-night coverage. These units also use a 2 MP outdoor network speed dome camera. Aside from the smart features, the technology, the PTZ offers 30x zoom to hone in on crucial details.
The technology has come a long way.
The first infrared linescan system was the British Yellow Duckling of the mid-1950s.It used a continuously rotating mirror and detector, with scanning by the motion of the carrier aircraft. Although unsuccessful in its intended application of submarine tracking by wake detection, it was applied to land-based surveillance and became the foundation of military uses.
Today, thermal cameras are popular for guarding physical and virtual perimeters around power plants, petrochemical facilities or substations as well as locations. Thermal cameras have an important role to play at night or in poor visibility without supplementary illumination from lights or lasers.
The thermal approach coms packaged in numerous configurations. For example, some cameras, for example the Flir IP Motorized IP Cameras, offer HD picture quality with night vision capabilities. They often boast integrated Power over Ethernet (PoE) and remote zoom and focus adjustment, allowing for single cable installation in indoor and outdoor installations and cold climates.
Also within the thermal family are other sophisticated cameras such as wireless HD units (the Flir FX as another example), boasting features including rapid recap, smart zone, 1080p HD and Wi-Fi connectivity.