CCTV GUIDE & PRICES
The latest CCTV camera technology is advanced and sophisticated, requiring specialist knowledge to install and set up correctly. There is a vast array of CCTV security options, together with technical terminology that you may not have heard of before. So SafeCity decided to create this easy read guide to help you understand CCTV cameras better when considering the best-Closed circuit TV installation for your home or business.
CCD Chip Size & Chip Sets
The main function of a CCTV camera is to capture light and convert it into a perfect video signal. At the core of a CCTV camera is a CCD sensor (Charge Coupled Device). This converts light into an electrical signal. Signal processing converts the electrical signal to a video signal that can be displayed on the screen or recorder. A typical CCD is made up of optical detector integrated circuits that use semiconductors. The CCTV camera lens focuses light on the CCD image sensor. Photodiodes sense the image areas of light and dark and this results in an electrical charge in proportion to the level of light. Then the brighter area will result in a higher charge. The photodiodes form a matrix of rows and columns and are called picture cells or Pixels. The charge on the diodes is then processed. CCDs have a variety of surface sizes, typically 1/2 inch, 1/3 inch, 1/4 inch and 1/8 inch. To summarise, these are not the actual sizes of the sensors, but based on their video camera tube equivalent, as historically, image sensors were used to replace video camera tubes, so a sensor with a 1/4 inch digital sensor is more accurately described as a ‘1/4 inch video camera tube equivalent’.
Analogue Versus Digital CCTV Cameras
What is Analogue CCTV? In an analogue camera system, the camera captures an analogue signal and this is transferred via a coax cable to the DVR (Digital Video Recorder). The DVR converts the analogue signal to a digital one, compresses it and this is stored on a hard drive within the DVR. The footage can be viewed on monitors attached to the DVR or the signal can be sent across a network to be viewed on a computer screen. The DVR can be set up to transmit over the internet and when this is done with an analogue system, all of the cameras’ signals are sent as one stream using one IP address and this makes it very efficient.
Digital IP Network Camera
With digital IP (Internet Protocol) cameras, each camera captures an analogue signal, but this is converted to a digital signal within the camera itself. Digital processing may also occur within the camera. The digital signal is then sent via a LAN (Local Area Network). The cables used here are Ethernet, e.g. Cat5e. Instead of the analogue system’s DVR, for IP cameras, the video from each camera is compressed and recorded onto an NVR (Network Video Recorder). The key difference is that the signal is digital and a much higher resolution (see further down in this guide) than analogue. The NVR streams the video from all cameras and broadcasts over LAN and over the internet for remote viewing.
WIRED CAMERAS
ADVANTAGES DISADVANTAGES
Limited interference from other devices More difficult to install
Signal is not easily hacked or jammed
Holes drilled in walls to feed cables
Good for different protected zones
Not portable and easily moved to another location.
Good for large buildings
Picture quality better than wireless
Signal more stable than wireless
WIRELESS CAMERAS ADVANTAGES DISADVANTAGES
Quick and simple to install
Can be affected by interference causing failure or false trigger of motion detection
No holes in wall required
Potential to be hacked
Cameras can be located anywhere but need to be within Wifi range
More expensive than wired systems
Portable and can easily be moved to another building
Needs one cable for power
CCD Chip Size & Chip Sets
The main function of a CCTV camera is to capture light and convert it into a perfect video signal. At the core of a CCTV camera is a CCD sensor (Charge Coupled Device). This converts light into an electrical signal. Signal processing converts the electrical signal to a video signal that can be displayed on the screen or recorder. A typical CCD is made up of optical detector integrated circuits that use semiconductors. The CCTV camera lens focuses light on the CCD image sensor. Photodiodes sense the image areas of light and dark and this results in an electrical charge in proportion to the level of light. Then the brighter area will result in a higher charge. The photodiodes form a matrix of rows and columns and are called picture cells or Pixels. The charge on the diodes is then processed. CCDs have a variety of surface sizes, typically 1/2 inch, 1/3 inch, 1/4 inch and 1/8 inch. To summarise, these are not the actual sizes of the sensors, but based on their video camera tube equivalent, as historically, image sensors were used to replace video camera tubes, so a sensor with a 1/4 inch digital sensor is more accurately described as a ‘1/4 inch video camera tube equivalent’.
Analogue Versus Digital CCTV Cameras
What is Analogue CCTV? In an analogue camera system, the camera captures an analogue signal and this is transferred via a coax cable to the DVR (Digital Video Recorder). The DVR converts the analogue signal to a digital one, compresses it and this is stored on a hard drive within the DVR. The footage can be viewed on monitors attached to the DVR or the signal can be sent across a network to be viewed on a computer screen. The DVR can be set up to transmit over the internet and when this is done with an analogue system, all of the cameras’ signals are sent as one stream using one IP address and this makes it very efficient.
Digital IP Network Camera
With digital IP (Internet Protocol) cameras, each camera captures an analogue signal, but this is converted to a digital signal within the camera itself. Digital processing may also occur within the camera. The digital signal is then sent via a LAN (Local Area Network). The cables used here are Ethernet, e.g. Cat5e. Instead of the analogue system’s DVR, for IP cameras, the video from each camera is compressed and recorded onto an NVR (Network Video Recorder). The key difference is that the signal is digital and a much higher resolution (see further down in this guide) than analogue. The NVR streams the video from all cameras and broadcasts over LAN and over the internet for remote viewing.
WIRED CAMERAS
ADVANTAGES DISADVANTAGES
Limited interference from other devices More difficult to install
Signal is not easily hacked or jammed
Holes drilled in walls to feed cables
Good for different protected zones
Not portable and easily moved to another location.
Good for large buildings
Picture quality better than wireless
Signal more stable than wireless
WIRELESS CAMERAS ADVANTAGES DISADVANTAGES
Quick and simple to install
Can be affected by interference causing failure or false trigger of motion detection
No holes in wall required
Potential to be hacked
Cameras can be located anywhere but need to be within Wifi range
More expensive than wired systems
Portable and can easily be moved to another building
Needs one cable for power
