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Technologies in video surveillance

Technologies in video surveillance

Having to install video surveillance cameras you are faced with the choice of technology.

There are several types of technologies in video surveillance: Analogue (also called D1 or WD1), HDCVI, HDTVi, AHD and IP.La difference lies in the image quality, which is critical to have clear, high definition, full of detail.

The resolutions are:

CIF                 = 320x288 PAL
HALF D1          = 720x288 PAL
D1                  = 720x576 PAL
WD1               =  960X576  PAL analog
HDCVI 720      = 1280X720 
HDCVI 1080    = 1920X1080 Full HD

The codes that we have listed are based more on signal transport acquired by the cameras, as during transport may leak signal and thus the image quality is degraded. It is therefore necessary to mention the video transport systems, and in particular video signal in its complex structure, also called composite video (CVBS), which comes from the cameras and went to the DVR (Digital Video Recorder).

The first to be developed, but which continues to have a considerable range of the market is undoubtedly the analog video surveillance system. The video signal in conventional analog installations is transmitted via coaxial cable with a CVBS signal. Displays video without transmitting audio.La spread of this technology is due to its low cost and its ease of use. Moreover, the fact of being present for years means that there is a great compatibility between different brands. The most obvious disadvantages are the lack of advanced features, the resolution and the difficulty to use it over long distances, because of signal distortion. Also the need to use a cable for each camera constitutes a limit for these plants.

With equivalent costs is obtained, by now, a much higher quality. new systems which are an evolution of the conventional CVBS, are called: HDCVI and HDTVI.

  • The HDCVI is a technology for the surveillance of transmissions based on the transmission through coaxial cable. The HDCVI (HIGHT DEFINITION COMPOSIT VIDEO INTERFACE) is a system of transmission of images characterized by the absence of transmission latency, long distance connectivity, simultaneous transmission of video, audio and data.

Then the installation system is structured with available Star where the DVR is the central point, and each camera comes to it with a single cable. The HDCVI offers two specific resolutions: 1080p (1920 × 1080) and 720p (1280 × 720) and features the patented ASC (Auto Signal Compensation), which allows an extremely low signal distortion for long-distance transmissions.

And 'possible on a single coaxial cable transmission of three different signals: video, audio and data. This unique characteristic of only HDCVI systems greatly simplifies the installation, reduces the costs of the materials required to carry audio and data control, increasing the video surveillance system functionality.

  • The HDCVI technology is designed to improve all aspects of performance on HD coaxial cables, making the devices in high definition.

HDTVi (High Definition Video Transport Interface) is the HD video transmission interface. HDTVi is a technology that can be implemented on existing systems with coaxial cable to provide reliable transmission of HD video signal. The HDTVi technology allows to increase the quality in the sending and receiving of the cameras, to improve the transmission distance (cable length), through advanced image processing technology, which further improves image quality, and at the same time, avoids the phenomenon of crosstalk simulation, the luminance and chrominance.

Maximum resolution 1920X1080 1920X1080
Compatible analog 960H/D1 NO NO
Transmission of 75-3 Coaxial @720p 500mt 300mt
Transmission of torque CAT5E 300mt 150mt
Audio transmission over cable YES NO
Controls transmission over cable YES YES
High-end devices available YES NO