As most of our attention is currently focused on the shift to IP video technology, it’s important to remember that analogue CCTV security cameras can still be very useful for many surveillance applications, particularly those on a budget. Traditional CCTV security cameras process and send the video signal in analogue format for local viewing from a single central monitoring point. That isn’t to say that analogue cameras can’t be used in an IP-based surveillance system. IP video encoders, as well as other equipment like digital video recorders and hybrid DVRs, allow you to keep your existing analogue cameras while transitioning to digital surveillance.
What is a CCTV security camera?
A CCTV camera is an analogue video camera that delivers signals to a single central location via coaxial cable for monitoring, recording, and video analysis. While IP network cameras are the current trend, CCTV cameras are still commonly utilized and provide a cost-effective solution to many typical surveillance applications.
Since the 1940s, CCTV technology has been there, and it became a prominent participant in the security sector around 1970. There are CCTV security camera models for nearly any surveillance application, and the technology is tried and true. Fixed cameras and pan/tilt/zoom versions, which can rotate horizontally and vertically to cover a larger area, are the two primary types of CCTV cameras.
CCTV Security Camera Types
PTZ
PTZ cameras are perfect for surveillance over a large area. They let operators to manage pan, tilt, and zoom features from a distance, allowing them to follow activities and zoom in for more extensive monitoring. Analog CCTV security cameras lag behind their IP camera counterparts in this area. The pan/tilt/zoom functions of IP cameras can be controlled manually or automatically and are transmitted through a single network cable, whereas analogue cameras require additional wiring to perform the same function.
Fixed CCTV surveillance cameras
Fixed security cameras have only one direction of view, making them ideal for monitoring relatively specific regions. They’re also preferable in situations where cameras must be installed in highly visible locations. As a result, fixed CCTV surveillance cameras are extremely efficient not just in catching footage of suspicious activity, but also in deterring criminals and vandals from committing their crimes in the first place. During installation, the camera’s direction is determined. Many security cameras also support replaceable lenses and housings, allowing you to satisfy a wide range of surveillance requirements.
Measuring CCTV Image Quality
Effects of Digital Conversion on Image Quality
The recording medium for most analogue CCTV systems today is a DVR. This enables the analogue signals to be digitised for recording and network distribution. While a DVR system is a cost-effective alternative to IP video and offers consumers vital features like digital storage and remote access, it also has downsides. The first is a small deterioration in image quality. Simply said, the many analog-to-digital conversions that occur from the camera to the recorder make it more difficult to maintain image quality in this type of arrangement. Cabling distance also plays a role, as the video signals become weaker the further they travel. Nevertheless, for customers who want to get some of the benefits of digital IP surveillance while using lower-cost CCTV security cameras, a DVR-based solution is a great option.
Understanding TVL Resolution
The picture detail of an analogue CCTV surveillance camera is commonly expressed in TVL (TV Lines) (or TV Lines). Consider the video image as a series of active horizontal lines. In two off-set fields, these lines are transmitted to a monitor or recording device. Even-numbered lines appear in one field, while odd-numbered lines appear in the other. Because the lines are interlaced, the spectator perceives a complete picture. Because the image has a 3×4 aspect ratio, the horizontal TVL resolution is determined by the amount of detail you can see in 3/4 of the image’s width. Most basic CCTV cameras have a TVL resolution of roughly 380, whereas high-resolution cameras have a TVL resolution of around 540.