As per the today’s changing environment and scenario, security cameras are need of every household, every office and every building and every society. Though, with the emergence of technology, security cameras have also traversed a long distance while adopting various technologies.
Let’s know everything about Security cameras to clarify your basics.
Security cameras are either analogue or digital which means they work on the basis of sending analogue or digital signals to a storage device such as a video tape recorder or desktop computer or laptop.
Analogue Cameras /DVR
Analogue Cameras basically allows you to record straight to a video tape recorder which is able to record analogue signals as pictures. Analogue signals can be converted to digital signals to enable the recording to be stored in PC as digital recordings. In that case the analogue camera must be directly plugged into a video capture card in the computer, and the card then converts the analogue signal to digital. These cards are relatively cheap, but inevitably resulting digital signals compressed 5:1 (MPEG Compression) in order for the video recordings to be saved on a continuous basis.
Another way to store recordings on a non-analogue media is through the use of a digital video recorder (DVR). Such a device is similar in functionality to a PC with a capture card and appropriate video recording software. Unlike PCs, most DVRs designed for CCTV are embedded devices that require less maintenance and simpler set up than a PC based solutions, for a medium to large number of analogue cameras.
Some DVRs also follow digital broadcasting of the video signal, thus acting like a network camera. If a device does allow broadcasting of the video, but does not record it, then it’s called a video server. These devices effectively turn any analogue camera into a network TV.
Digital Cameras do not require a video capture card because they work using a digital signal which can be saved directly to a computer. The signal is compressed 5:1, but DVD quality can be achieved with more compression. The highest picture quality of DVD is only slightly lower than the quality of basis 5:1 compression DV.
Saving uncompressed digital recordings taken up an enormous amount of hard drive space, and a few hours of uncompressed video could quickly fill up a hard drive. Holiday uncompressed recordings may look fine but one could not run uncompressed quality recordings on a continuous basis. Motion detection is therefore sometimes used as a work around solution to record in uncompressed quality.
However, in any situation where standard-definition video cameras are used, the quality is going to be poor because the maximum pixel resolution of the image chips in most of these devices is 320, 000 pixels (analogue quality is measured in TV lines but the results are the same). They generally capture horizontal and vertical fields of lines and blend them together to make a single frame. The maximum frame rate is normally 30 frames per second.
Network IP cameras
IP cameras or network cameras are analogue or digital video cameras, plus an embedded video server having an IP address, capable of streaming the video.
Because network cameras are embedded devices, and do not need to output an analogue signal, resolutions higher than CCTV analogue cameras are possible. A typical analogue CCTV camera has a PAL (768 x 576 pixels) or NTSC (720 x 480 pixels), where as normal cameras may have VGA (640 x 480 pixels), SVGA (800 x 600 pixels) or quad – VGA (1280 x 960 pixels, also referred to as “megapixel”) resolutions.
An analogue or digital camera connected to a video server acts as a network camera, but the image size is restricted to that of the video standard of the camera. However, optics (lenses and image sensors), not video resolutions, are the components that determine the image quality.
Network cameras can be used for very cheap surveillance solutions (requiring one network camera, some Ethernet cabling and one PC), or to replace entire CCTV installations (cameras become network cameras, tape recorders become DVRs and CCTV monitors become Computer with LED screens and specialized software. Digital Video Manufacturers claim that turning CCTV installations into Digital Video installations in inherently better).
What is an IP Camera?
An Internet Protocol Camera or IP camera is a type of Digital Video Camera commonly employed for surveillance, and which, unlike analogue CCTV Cameras, can send and receive data via a computer network and the Internet. Although most cameras that do this are webcams, the term IP Camera is usually applied only to those used for surveillance.
There are two kinds of IP Cameras:
- Centralized IP cameras, which require a central video recorder (NVR) to handle the recording, video and alarm management.
- Decentralized IP cameras, which do not require a central NVR, as the cameras have recording function built-in and can this record directly to any standard storage media, such as SD cards, NAS (Network Attached Storage) or a PC/Server/
IP cameras may differ from one another in features and functions, video encoding (compression) schemes, available network protocols, and the API to be used by Video Management software.
Advantages of IP Camera
IP Cameras are widely considered as the wave of the future for security camera surveillance systems. IP cameras which transmitted video signals as a voltage, instead IP camera images are sent using the transmission and security features of the TCP/IP protocol, which provide numerous benefits.
- Two way audio via a single network cable allows users to listen to and speak to the subject of the audio.
- The use of a Wi-Fi or wireless network
- Distributed intelligence such as video analytics can be placed in the camera itself allowing the camera to analyze images
- Transmission of commands for PTZ (Pan, Tilt and Zoom) cameras via a single network
- Secure data transmission through encryption and authentication methods such as WPA, WPA2, TKIP, AES.
- Remote accessibility, which allows live video from selected camera to be viewed from any computer, mobile smart phones and other devices
- PoE (Power over Ethernet) to supply power through Ethernet cable and operate without a dedicated power supply.