Glossary of IP Surveillance Terms
With an auto-iris lens, the iris is controlled automatically to regulate the amount of light entering the camera. This is ideal for camera installations in outdoor locations, high-contrast situations, and areas where lighting conditions fluctuate.
CCD Image Sensor
A CCD image sensor is a light-sensitive image device available in many IP network cameras. The sensor transforms light into electronic signals. CCD sensors provide strong light sensitivity allowing for video surveillance in low-light conditions.
CCTV (or closed-circuit television) refers to the use of analog surveillance cameras to submit a video signal to a specific set of monitors. Since a CCTV system is closed, only a limited number of viewers can access the footage from a single location. With the arrival of IP-based surveillance, analog CCTV systems are now being superseded by improved digital technology.
Ethernet is a standard technology for network communications in LANs (Local Area Networks). Ethernet LANs use twisted pair cabling, with network devices connecting to a central cable or hub. The most common Ethernet systems are 10BASE-T and 100BASE-T10, which transmit data at speeds of 10 Mbps and 100 Mbps.
Field of View
The field of view represents the complete area of coverage provided by a network camera when viewed at full frame. Field of view can be determined by camera type, lens, and image resolution.
FTP (File Transfer Protocol) is a network protocol used to transfer files from one computer to another, or between devices on the network. An FTP client can connect to an FTP server to access and manipulate the files stored on that server.
Image compression reduces the file size of video images to optimize bandwidth while streaming surveillance footage. The most common compression technologies for IP network cameras are Motion JPEG and MPEG-4. H.264 is the latest compression technology that significantly reduces the file size of high-quality video images.
JPEG is a method of compression for photographic images. The amount of compression can be controlled to allow for a tradeoff between image quality and file size. JPEG is the most commonly used format for storing and sending images over the internet.
IP (Internet Protocol)
IP (Internet Protocol) is a connectionless protocol used for transmitting data over a network. Data is divided into independent packets containing the IP address of both the sender and the recipient. Each computer or network device has its own unique IP address.
An IP address is the unique address of a computer or network device connected to that network. IP addresses allow those network computers and devices to locate each other and transfer data back and forth.
An IP camera (or network camera) captures and transmits live video images directly over an IP network. Each camera has a built-in web server and its own IP address. IP cameras allow for remote viewing, recording, and management from anywhere using a web server or video management software.
A LAN (Local Area Network) is a grouping of computers and network devices that share common resources within a small physical area, for instance an office building or school. LANs usually offer high data transfer rates and use Ethernet or Wi-Fi for network communication.
Lux refers to a standard unit of measure for illumination. In relation to network cameras, lux is the measure of low-light sensitivity provided by the camera.
Megapixel IP Camera
Megapixel IP cameras provide exceptionally high image detail and are the ideal choice for video surveillance applications where clear identification of people and objects is critical. A megapixel camera will also provide a broader field of view than a conventional surveillance camera, and allows users to zoom in on specific portions of a scene without a significant loss in image detail.
In terms of IP-based surveillance, motion detection is a network camera application that allows users to trigger events such as recording, high-quality video streaming, and automated alerts to occur only when motion is perceived. Motion detection helps to optimize bandwidth and preserve storage space.
Motion JPEG (MJPEG) is a simple compression technique used to stream digital video images across a network. The quality of the image is guaranteed, regardless of movement because the captured video is a series of separately compressed JPEG images that can be extracted individually. The compression level can be adjusted to control image quality and file size.
MPEG refers to a set of standards for audio and video compression. The acronym MPEG stands for Moving Pictures Expert Group, a group formed by ISO to set these compression standards. Each compression standard is designed for a different purpose.
MPEG4 is a video and audio compression technology found in many IP network camera models. The MPEG4 compression standard aims to deliver superior image quality while optimizing bandwidth.
A network camera (or IP camera) captures and streams live video images directly over an IP network. Each camera has its own IP address and features a built-in web server. Network cameras allow for remote viewing, recording, and video management from anywhere using a web server or video management software.
Network Video Recorder
A Network Video Recorder (NVR) is a hardware box that receives video streams over a LAN or WAN and captures them onto hard disk in digital format. Recording and playback can be managed remotely using a network PC.
IP cameras with panning capabilities can move back and forth horizontally in order to monitor wider areas. In many cases a camera's panning functionality can be controlled remotely from a network PC using video management software.
Power over Ethernet (PoE)
With Power over Ethernet, a network device, such as an IP camera, receives power and transmits video and data over a single Ethernet cable. This allows for flexible installation in locations where power outlets aren't readily available.
PTZ (pan/tilt/zoom functionality) is a feature available in many IP camera models. PTZ allows users to monitor large areas with a single network camera. Pan, tilt, and zoom functions can be controlled remotely so operators can follow activity and focus in on specific details.
Resolution is the measure of how much detail an image can hold. The higher the resolution the more detailed the images are. In the case of IP cameras, resolution is usually specified by pixel-count.
In general, a server is a computer program, or a computer running a server program, that provides services to other computer programs. A server appliance is a network-connected hardware appliance that provides dedicated applications to a network, while a web server is a computer program that delivers requested html files and pages to the client.
A tampering alarm is a sophisticated application found in some network cameras that can detect when a camera is being tampered with. The alarm can be triggered by potential acts of tampering, for instance if the camera lens is adjusted, obscured, or covered up.
Tilt refers to an IP camera's ability to be directed up and down in a vertical plane. The camera lens can be aimed at a specific part of a scene, and in many cases the tilt can be controlled remotely.
A video server is a computer-based device dedicated to delivering video streams online. In terms of IP-based video surveillance, a video server converts video footage from analog security cameras into digital IP video streams. This allows users to incorporate existing analog cameras into an IP surveillance system.
Wireless Network Camera
Wireless network cameras are able to connect to a network wirelessly, allowing for flexible installation in virtually any location. In general, wireless IP cameras are recommended for use in areas where the installation of cables isn't feasible, and for surveillance applications where cameras will be moved and repositioned regularly.
WPA (Wi-Fi Protected Access) is a wireless encryption standard that indicates compliance with security protocol established by the Wi-Fi Alliance to secure wireless networks.
Zoom functionality is available in many network camera models. It allows users to zero in on specific details and areas of a scene, and can often be controlled remotely.