Top ten installation challenges

Advanced image features

When installing advanced network cameras, be sure to take advantage of all the camera’s image capabilities. 

Day and night functionality

All types of network cameras —fixed or otherwise — can offer day and night functionality. A day/night camera is designed for outdoor use or in indoor environments with poor lighting.
A day/night network camera delivers color images during the day. When the light falls below a certain level, the camera can make use of near-infrared (IR) light, by automatically switching to night mode, in which images are produced in high-quality, black and white.

Near-infrared light (700-1000 nm) is beyond what the human eye can see, but most camera sensors can still detect and use it. When there is plenty of light, a day/night camera uses an IR-cut filter to block the IR light so that it doesn’t distort the other colors in the image. When the camera is in night mode, the IR-cut filter is removed, thus boosting the camera’s light sensitivity to 0.001 lux or lower.

Figure 5: Graph illustrating how an image sensor responds to visible and near-IR light. Near-IR light is in the range 700-1000 nm.

Figure 6:  To the left, a schematic showing the IR-cut filter in a day/night network camera. At center, the position of the IR-cut filter in normal light/daylight. At right, the IR-cut filter removed in darkness.  

Day/night cameras are useful in environments that restrict the use of artificial lighting. These include low-light video surveillance situations, covert surveillance, and other discreet applications, for example in traffic surveillance, where bright lights would disturb drivers at night.

Wide Dynamic Range (WDR)

A scene that contains extremes of lighting at both ends of the scale, i.e. very bright and very dark areas, is said to suffer from Wide Dynamic Range (WDR). This is often found in backlit scenes, e.g. in front of a window with a lot of sunlight coming in. In many other cameras, this would result in an image where objects in the dark areas would hardly be visible. Wide dynamic range is counteracted by applying techniques such as using different exposures for different objects in the same scene, making objects visible in both the bright and dark areas.

WDR is typically encountered in the following scenes:

  • Entrance doors with daylight outside and a darker indoor environment
  • Vehicles entering a parking garage or tunnel, also with daylight outside and low light inside
  • Vehicles with bright headlights, moving directly toward the camera
  • Environments with lots of reflected light, for example in office buildings with many windows, or in shopping malls

Figure 7: The first two images show how the wide dynamic range in the monitored scene causes parts of the image to be overexposed or underexposed. In the image to the right, WDR dynamic capture has been used, resulting in a balanced image with all areas visible.

Lightfinder

Axis’ revolutionary Lightfinder technology is the result of the meticulous pairing of sensors lenses, along with the processing of the data produced by the sensor-lens combination. The end-result is network cameras with outstanding low-light performance.

Lightfinder technology makes a camera highly sensitive to light, allowing the camera to “see” even in very dark conditions, as well as maintain focus in both daylight and infrared light.

Lightfinder technology is especially beneficial in demanding video surveillance applications such as construction sites, parking lots, perimeters and city scenes. In contrast to conventional day/night cameras that switch to black & white in darkness, a Lightfinder camera can display colors even in very dark conditions, which can be an important factor for successful identification of people, vehicles and incidents. The camera’s extreme sensitivity to light means that IR illuminators are often not required, which cuts down on installation costs.

Figure 8: Comparison between a standard network camera and an AXIS Q1602 camera in a low-light scene (0.3 lux).  

Camera placement