Network Camera Considerations
IP network cameras are essentially a camera and computer in one. These cameras capture and transmit video across an IP network, which allows for both local and remote viewing and video management. IP cameras connect to your existing IP network just like any other network device. The advantages of network cameras over analog equipment include remote monitoring, digital storage, cost-effective installation, flexibility, and scalability should you need to install additional cameras down the road. IP cameras are available in countless makes and models offering limitless surveillance possibilities. Choosing the right network camera setup depends on the specific needs of your surveillance application.
Types of IP Cameras
The variety of wireless network camera models available allows users to install video security solutions fit for any surveillance application. Here are some of the more common IP camera types.
The 3 types of image sensors
Surveillance camera technology, like all image based technology, is based on light. When light passes through a camera lens, it goes to the image sensor and activates the pixels on the sensor. Each pixel registers the amount of light it sees, and this creates the image your camera records. When it comes to network camera software, there are three types of images sensors to choose from.
Charge-coupled devices, or CCD image sensors, have been used in cameras for more than 30 years and are important when discussing network security cameras. They specialize in low-light situations to create images that are less noisy, as their sensors are more sensitive to light than CMOS sensors. CCD sensors are more expensive and complex than other sensors, and can use up to 100 times the power a CMOS sensor would use.
Also known as complementary metal-oxide semiconductors, CMOS sensors have a faster readout which allows them to produce high-resolution images. CMOS sensors are smaller, easier to integrate into cameras, and use less power than their CCD counterparts. Although they were originally developed for use in memory chips for PC’s, CMOS technology has been growing rapidly.
Megapixel sensors contain a million or more pixels, allowing them to produce extremely clear images. But for cost and size reasons, the pixels are smaller than traditional VGA sensors. This makes the megapixel sensor less sensitive, and works best in stable light conditions.
Network cameras are built with image sensors available in a variety of sizes such as 2/3, 1/2, 1/3, and 1/4-inch sensors. IP camera lenses are designed to work with these sensors, and to get optimal image quality without black corners or lost information, it's best to use a lens that's the same size as the image sensor. Knowing the size of your sensor is important when figuring out network security camera considerations.
Many IP network cameras accept interchangeable lenses for different surveillance applications. When choosing the right camera lens for your network camera software needs, there are several factors to consider:
The focal length is what determines the horizontal field of view at a certain distance. As the focal length gets longer, the field of view narrows. The lens can offer either manual iris control or automatic iris control. With manual iris control, the lens is set to an average value to be used in varying light conditions. Lenses with automatic iris control, such as DC auto iris lenses, are preferred for outdoor applications, and locations where light can change dramatically throughout the day. The lens is able to adjust as the light changes.
The role of the iris in the network camera lens is to adjust the amount of light that passes through.
A lens's f-number determines the amount of light admitted to the sensor. The smaller the f-number, the more light is admitted to the sensor. For this reason, low f-numbers allow for better image quality in low-light situations.
Security Camera Housings
A variety of IP network camera housings are available to ease installation and to help protect network cameras from tampering, vandalism, and harsh conditions such as extreme cold, humidity, dust, moisture, and more.
For IP cameras placed in vulnerable areas, vandal-proof housings are an excellent option. They're available for both indoor and outdoor surveillance applications, and typically feature sturdy metal construction, an impact-resistant dome or window, and tamper-resistant screws.
Fixed IP Camera Housings
Designed to offer protection for fixed network cameras, these housings are available for indoor and outdoor surveillance setups. They work to protect and cover network cameras, and come in various forms for mounting on ceilings and walls.
Outdoor network cameras housings are built to be weatherproof, resistant to moisture, and sometimes even feature built-in fans and heaters for both cold and hot environments. The housings come in different sizes to handle different camera types such as fixed IP cameras and PTZ domes, and are also available in vandal-proof versions for hostile environments.
Power over Ethernet (PoE)
Power over Ethernet (or PoE) is a technology that allows LAN-enabled devices, such as network cameras and IP telephones, to be powered over an IP network infrastructure using standard Ethernet cabling. In the case of an IP-based surveillance system featuring PoE cameras, each individual camera transmits data and receives power via a single Ethernet cable, eliminating the need for complicated and expensive cabling because the system operates along an existing network.
Power over Ethernet allows for flexible camera installation as network cameras can be placed in areas where power outlets aren't readily available. This means users can actually install the cameras where they're needed, not just where the AC sockets are. Power is supplied directly from the data ports that the cameras and other network devices are connected to. Users can also install Wireless LAN access points for even greater flexibility.
Another benefit of PoE technology is it enables easy installation of UPS (uninterruptible power supplies) for video surveillance applications requiring 24-hour surveillance that will continue even during power outages.
Wireless network cameras are primarily used in situations where the installation of extra cabling in a building could cause damage, or in locations where cameras need to be frequently repositioned. Basically, we're talking about video surveillance installations where a wired solution is impractical, or installations requiring the mobility that a wireless solution provides.
The most common modes of wireless communication are wireless LANs and wireless bridges. A wireless LAN is just what it sounds like – a wireless local area network. Wireless LANS are typically setup indoors and cover short distances. The standards for this type of wireless network are usually well defined so products from different vendors can operate together on the same network.
Wireless bridges are used to connect buildings or multiple sites together using a point-to-point data link that allows data to travel long distances at high speeds.
Megapixel cameras take video surveillance to the next level by providing much higher resolution than traditional security cameras. The improved resolution not only results in clearer video images, it also significantly increases the camera's field of view without any loss in image detail. In fact, a single megapixel camera can monitor areas that would ordinarily require multiple surveillance cameras. Consider how many cameras it takes to monitor locations such as casinos, parking lots, construction sites, and retail stores. In a parking lot, for instance, it's now possible for a single megapixel camera to cover the entire area. And because of the high resolution and greater image detail, surveillance operators can zoom in on specific portions of the recorded scene to identify individuals and license plate numbers. It's all about enhancing the quality of the recorded images, as well as providing high-definition live video streams.
Megapixel network cameras are especially useful for surveillance applications where details are critical for identification purposes. Banks, airports, and other high-security areas are good examples, as are retail locations requiring point-of-sale monitoring. But with camera prices dropping as the technology becomes more readily available, the use of magapixel cameras for all types of surveillance applications is sure to increase steadily in the coming years.
Video Compression Standards
In the world of IP cameras, the main aim of video compression is to optimize network bandwidth and storage capacity by reducing video files sizes. The catch, however, is to maintain high-quality video images. A number of compression technologies are currently available in different network camera models, each aiming to provide the best possible compression ratio for specific video management functions.
A common compression standard available with most network cameras is Motion JPEG. By using Motion JPEG, a network camera is able to present video as a series of individual JPEG images. The frame rate can be adjusted, and any frame rate at or above 16 frames per second is considered full motion video.
MPEG-4 is another very common compression technology found in IP cameras. With MPEG-4 the bit-rate of images is lowered to meet whatever level of image quality is required for a specific surveillance application.
H.264 is latest video compression standard. It improves upon Motion JPEG and MPEG-4 in significantly reducing digital file sizes without compromising image quality. The benefits of H.264 include reduced storage and bandwidth costs, higher resolution and frame rate, and improved megapixel camera performance.