Q&A with Mike Capulli, SAMSUNG GVI Security - Page 2Written by Staff 03 December 2008
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SP&T: What if a customer wants to stick with analogue today but knows they will be going to IP tomorrow?
CAPULLI: It’s happening all the time. Integrators want to make sure that their system choices provide an upgrade path that is forward-compatible with a future of fully digital IP/digital architecture. This can be done without throwing out perfectly good analogue equipment. To maximize the customer’s technology choices at the camera, the transmission system and the head end, leading video systems suppliers and integrators are providing products that “connect the dots” between installed analogue and digital equipment and between security- and IT-based perspectives.
Joining analogue equipment to the digital future is facilitated by the adoption of UTP as the transmission medium. Fortunately, there is a way to implement a cost-effective hybrid UTP system that gives customers the product choices they need. A UTP-based hybrid solution supports today’s cost-effective analogue systems while providing the IP ready cabling infrastructure when a switchover does occur.
For integrators who want to implement a digital-ready structured cabling system that easily supports a wide variety of existing analogue products, a Power-Video-Data (PVD) solution supports cameras with a single four-pair cable. Integrators can deliver a high quality picture over the same infrastructure used by Ethernet datacom systems. In fact, most facilities already have UTP cable for their phones and datacom needs.
There is a full range of UTP EIA 568B compliant CCTV transmission products featuring RJ45 connectivity. Power-Video-Data (PVD) products now let Integrators standardize their structured cabling in accordance with EIA 568B wiring protocols, reduce installation time, and fully prepare the plant wiring for future digital systems when desired.
The PVD solution provides a convenient, cost effective and future-proof way to connect power, video and data from the camera to the control room. These products provide interference rejection that lets video signals co-exist in the same wire bundle as telephone, datacom, or low-voltage power circuits. Thus, the installer can fully leverage the existing cabling infrastructure in accordance with EIA 568B wiring standards, while reducing costs and time of installation.
SP&T: How else can “future proofing” be put into play?
CAPULLI: The “middle of the road” of video surveillance is upgrading video surveillance by utilizing a Digital Video Recorder (DVR). A DVR system is not really fully IP-based, but is step toward the more advanced IP technology. In actuality, a DVR system uses the same camera and structures for cabling as the older CCTV analogue systems, but the old VCRs and multiplexers have been replaced with DVR for storage of the data. The data is converted to digital so that it can be stored on hard disks, but the quality of the images captured remains analogue since this is how it originated. In other words, analogue signals are fed from the cameras to the DVR where they are converted into digital signals for storage and/or transmission over digital networks.
SP&T: Aren’t there often problems with clarity though?
CAPULLI: In such applications, one must be very careful of image degradation. That’s because analogue and digital use different video display methods. The signal coming from the analogue cameras is interlaced while digital monitors and DVRs want progressive scan.
SP&T: What’s the difference?
CAPULLI: Interlaced means the lines that make up the picture on the analogue monitor are drawn in an alternating fashion. In the U.S., first the even lines appear on the screen, then the odd lines appear. During interlace display scanning, the screen is refreshed in two top-to-bottom passes such that the lines scanned in one pass are positioned between the lines drawn in the previous pass.
Progressive scan means the lines that make up the monitor picture are displayed all at once in sequence. It renders all lines in a single top-to-bottom pass, which requires twice as much data per pass as interlaced scanning.
Therefore, when moving from analog to digital, the video data format must be converted from one that is compatible with interlaced fields to one that provides progressive frames prior to rendering on a digital display. The process of translating received interlaced video signals into a progressive scan format for output and display on any digital display is called de-interlacing. Properly processing the video from its native interlace form factor to high quality progressive-scan data is extremely important to the overall quality of the resulting image. Not only will any de-interlacing artifacts be visible, but they also increase the work that the codec must do to compress the image, resulting in lower quality at a given data rate.
SP&T: Can any DVR do this?
CAPULLI: The transformation is done in the DVR but not all DVRs are created equal. Before selecting one type of product over another, the user wants to literally see results. Here’s why. If the cameras are analogue and the monitor is digital, de-interlacing creates a progressive scan at the DVR and passes it on to the digital monitor. But, when the user wants to get a couple more years out of the analogue monitor, the progressive scan needs to be reconverted back to the interlacing method. This is the step at which the image can get softened and jaggy. Samsung, for instance, has put a great deal of work into its monitors, both digital and analogue, to assure images are crisp, no matter which type of system is to be deployed.
SP&T: Thanks, Mike.
CAPULLI: Thank you.
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