School CCTV Guide

School CCTV Introduction

A comprehensive school CCTV security solution should have two key focuses:

To create the maximum perceived risk in the mind of the potential wrong-doer.
To be able to capture and archive any incidents should they still take place, with sufficient image quality to be able to identify, discipline and/or prosecute with confidence.

The key here is the level of perceived risk that the CCTV system creates - it is far preferable for schools to deter the potential wrong-doer in the first place than to suffer the crime, identify, catch and potentially prosecute.

CCTV is increasingly being used for non security applications such as traffic monitoring, hazardous environment viewing, on-board motorsport filming, and wildlife observation. However, whatever application CCTV is being used for the constituent parts of the system are always basically the same.

Types of School CCTV systems

There are a plethora of CCTV systems available for both commercial and public sector use. In the most basic format a single CCTV system can be set up to monitor activity and to record it directly to a localised recording device. More complex systems can use multiple pan, tilt and zoom cameras (PTZ) that are monitored from a central control panel as well as being viewable/controllable over the network. How much past footage the system will record and archive depends on the system - increasingly the recording medium is moving away from VCR and towards Digital Video Recorders (DVRs). Some DVRs have hard drives only able to record 1 - 2 days worth of footage, with the more powerful DVRs having the ability to record months of real-time video with audio.

School CCTV Terminology and Definitions

Analogue: - Two main formats exist for representing data in electronics - Analogue, and Digital. Analogue relates to a mechanism that represents data by measurement of a continuous physical variable, as voltage of pressure.
AVI: - Audio Video Interleave - An audio-video standard designed by Microsoft.
Cameras: - School CCTV cameras come in all shapes, sizes and types: black and white, colour, interior, exterior, wired, IP, wireless, as well as dome, PTZ and covert. CCTV is seeing a steady rise in cameras that use the network to get back to their recording device, these are called IP cameras. Some IP cameras are even able to take their power from the ethernet too (PoE). However, the actual cost of IP cameras currently negates their use in all but the biggest installations.
Compression: - If using a digital CCTV system then it will most likely use compression to reduce the size of the files it records. MPEG4 is the preferred format.
Control panel: - Control panels range from basic TV screen monitoring functions right through to complex systems that can automatically monitor multitudes of 'zones' covered by the system. The control panel manages the pre-set zones which are designated areas that need to be monitored. Thus, a control panel on a simple system may monitor the outside of a building where a more complex system may monitor multiple zones both inside and outside the building. With CCTV being increasingly viewed over the network this means that control panels are becoming virtual software applications rather than actual hardware sitting on the desk.
Digital signal processing (DSP): - This function improves the quality of recordings by adapting the video signal to digital format to ensure the best results.
Digital System: - School Digital CCTV systems are only recently gaining popularity. Most security cameras are still analog, though DVRs are becoming the industry standard. There are some digital cameras available but they are extremely expensive. Most new systems installed today will include analog security cameras and a DVR. Any CCTV security camera system that includes a DVR is considered a Digital System.
DVR: - Digital Video Recorder - A Digital Video Recorder is effectively a mini computer that coverts the incoming (analog) signal from cameras to digital, and compresses and stores the data. The school DVR replaces the function of a multiplexor and a security VCR.
Frame rate: - Frames Per Second refers to the number of video images that can be captured, displayed, or recorded in a second. Also referred to as the 'frame rate' or 'refresh rate'. Typical CCTV systems record between 4 and 7 frames per second. Where incidents can happen very quickly it is advisable to have 12 frames per second or more. Real-time is generally accepted to be 30 frames per second.
Housing: - The covering or container of some cameras designed to protect from it from the weather and/or vandalism.
IP: - Internet Protocol Address is a unique address given to certain computer or electronic devices. An IP address is necessary for devices to identify and communicate with each other. An IP address is required for positive unique identification of any device on a network or the internet.
IP Cameras: - Cameras that use the network to travel back to the NVR, rather than being individually wired.
IR: - Infrared radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. The name means "below red", red being the colour of visible light with the longest wavelength. Infrared Security Cameras have special infrared lights installed around the outside of the camera lens. Through use of this special light the camera can capture a good picture even in total darkness.
JPEG: - Pronounced &jay-peg& and stands for &Joint Photographic Experts Group& who designed the standard. This is a standard way of compressing images which works particularly well for photographic images (as opposed to graphic art).
Keypads: - Many CCTV systems come with a keypad that is located away from the control panel and can be used to manage any security/alarm system that is part of the CCTV system.
Lenses: - There are many lens options with CCTV cameras that can alter the quality of the images recorded by it. For example, a camera with an auto iris lens will automatically adjust when light conditions change. One with a varifocal lens can be manually adjusted by the user. Some cameras come with a ready installed lens for convenience.
LUX: - This term shows how sensitive a CCTV camera is to the light levels present. If a camera has a LUX of 0 then it will be able to record in virtually no light.
Motion detectors: - A feature in some VCRs and DVRs to only begin recording video if something in the image moves or changes. Good for monitoring an area that is not heavily trafficked, and saves a lot of hard drive space.
Mounts: - Brackets and stands that fix the school CCTV cameras in situ.
Monitor: - Security camera monitors are used to display the images captured by your cameras. They come in analog and digital versions. Increasingly becoming LCD.
Multiplexer: - This is a CCTV monitoring system that facilitates the ability of more than one camera to be viewed at one time on numerous screens or split screens.
MPEG: - Pronounced "em-peg" and stands for "Motion Picture Experts Group" who designed the standard. This is a standard way of compressing audio and video files. (It's also the technology behind the now world-famous MP3 music files.)
PoE: - IP cameras that get their power from the Ethernet cable rather than requiring a separate power supply.
Pan tilt zoom (PTZ): - This term refers to a camera which can be moved remotely by a joystick or other remote control.
Pin Hole Camera: - Pin-hole cameras have a very small lens that can see through a small hole. These types of cameras are used in covert applications. A disadvantage of pin-hole cameras is that they require more lighting than normal cameras to capture a good clear picture.
Quad splitter: - This is a device that can split four cameras so that they can be displayed on one monitor.
Resolution: - Resolution refers to the number of lines that a CCTV system can show on a monitor. Resolution is usually displayed in the format of TVL.
Real-Time recording: - In digital video applications, 30 frames per second per camera (see above) looks just like real-time. There is no hesitation or jerkiness in the video.
Remote Viewing: - The ability to view your cameras from a remote location. Information is transmitted via phone line or internet.
Sensors: - CCTV that has sensors use infra-red (IR) technology to detect the changes of heat in a zone. When the system detects a certain type of movement between zones then it can be set to alert the user via an alarm and so on. If a PTZ camera is being deployed then the respective PTZ can be programmed so that it swivels round and focuses on the detected movement.
Smoke and heat detectors: - CCTV systems can also use smoke and heat detectors so that they provide an alert in the event of fire.
VCR: - A CCTV system that records to tape. These are becoming increasingly obsolete.
VR: - Some cameras are Vandal Resistant. Often these VR cameras are dome cameras are useful for tough environments.
Video Capture Card: - Computer cards that you can install on the motherboard of your own computer to create your own video recording computer.
Wireless: - Wireless CCTV systems are now readily available. Although you benefit from not needing wires, you often lose in relation to picture quality and the number of cameras that the system can handle.