How Do Night Vision Security Cameras Work?
Home security cameras with modern night vision capabilities provide an extra layer of protection for your family. Some of these cameras can create images from total darkness, allowing the capture of video images for unauthorized entry including vandalism and theft that are hidden from normal view. Improvements in design and technology have made might vision cameras more affordable in recent years, giving homeowners the option to maximize home security systems with minimal additional cost.
Night vision cameras capture images in low light conditions that ordinary security cameras fail to do. Incorporating a night vision camera in video surveillance systems will provide the highest level of protection for home and family.
How Night Vision Cameras Work
Security cameras with night vision capture images in the dark through low-light imaging, thermal imaging, or infrared illumination technologies.
- Low-light imaging cameras use image intensifiers that amplify available light to gain better vision. The image seen at low light is amplified through the action of the camera’s objective lens that focuses the available light to the photocathode of an image intensifier, which causes the release of a dense electron cloud that simulates an intensified version of the image seen in low light. The electron cloud eventually hits a green phosphor screen, making the phosphor glow and show the created image, which the camera captures. The rationale in the use of green phosphor is the capability of the human eye to differentiate more shades of green compared with other colors.
- The advantages of low-light imaging cameras include lower cost, high resolution and the capability to identify people, low power consumption, and enhanced visible imaging that yield the highest recognition or identification. On the other hand, low-light imaging will not work when there is total darkness, and can be damaged by situations that involve observing bright sources while under low light. The camera gives excellent images under low-light conditions but produces an inferior daytime performance.
- Thermal imaging technology do not require ambient light to function but operates on the principle that objects, particularly people, radiate heat that translates into the emission of infrared energy. The thermal imager collects infrared radiations that translate into electronic images. Objects captured by the thermal imager appear white when they are hot and black when they are cold. Some thermal imaging cameras show images in color to differentiate between objects at different temperatures. Cameras that function through thermal imaging are entirely independent from light, and can penetrate through fog, smoke, and haze to capture images. It employs either a cooled detector that is contained in a vacuum-sealed, cryogenically cooled case or an uncooled detector that operates at room temperature, costs much less, and is more appropriate for commercial applications.
Thermal imaging that employ an uncooled detector is relatively inexpensive and produces images with high contrast. The thermal imaging camera with an uncooled detector is ideal for video surveillance systems because it easily detects people and vehicles, and unlike the low-light imaging camera, it is not affected by light sources. It has high reliability but it is not appropriate for high-speed and multi-spectral applications.
- Infrared illumination employs an illuminator, which is either an LED type that utilizes an array of standard infrared emitting LEDs, or a laser type that employs an infrared laser diode that emits near infrared energy. This night vision camera is an ideal component of home security systems when coupled with motion detection technology because any movement detected by the camera triggers the infrared illumination and image capture. This camera type is appropriate for low-light video security systems that encompass perimeter protection.
- Infrared illumination has the lowest cost compared to other night vision cameras, and has the capability to perform video-capture at high speeds, for example capturing the license plates of moving cars. It produces good images by eliminating shadows to clearly reveal numbers, objects, and letters. The camera can penetrate mist, rain, and fog, and can see through windows.
Planning Home Security Systems with Night Vision
You have many decisions to make when planning for your home security system. These include the number of cameras to use, the integration of a night vision camera in the system, black and white or color options, choosing the indoor and outdoor models, and the Lux sensitivity of the system. While it is best to leave some decisions to security experts, you should be well-informed about the different choices that you can make so that you can actively participate in designing your home security camera system as well as control the cost of the home security project.
- You have to choose between a color security camera, and a black and white security camera that is appropriate for poor lighting conditions. The Lux rating of the color camera ranges from 1 to 4, and it will give you clear video footages that allow the identification of car colors, clothes, hair and other myriad details that are not apparent from a black and white camera. On the other hand, the black and white camera has very low Lux ratings for better image capture at night and emits minimal video noise. Color cameras are more expensive though the footages are easier to view than the black and white images.
- The system connectivity for home security can either be wired or wireless, depending on the environment where you plan to install these units. Wired systems are better when you want to extend the protection over a large expanse, both indoors and outdoors, that a wireless system cannot cover. On the other hand, wireless cameras are easier to set-up, less costly to install, and is easier to conceal but is limited by the reach of the wireless signal. You can also consider IP network cameras if you are planning for a comprehensive security system for both indoors and outdoors. The use of a network video recorder (NVR) allows better monitoring of security footages.
- Choose the appropriate models of security cameras for indoors and outdoors, and integrate a night vision camera in selected locations, for example the garage and perimeter areas. For outdoor cameras, choose units with the appropriate IP rating.
- Decide on the number of cameras to use indoors and outdoors. There should be no blind spots, which means you have identify the positioning of each camera and plan for the maximum number that will give a high level of security coverage.
Your choice of home security cameras defines the level of protection for your home, which should include night vision cameras for round-the-clock security.