Instant Access
Gone are the days of trawling through endless hours of video tape. With digital technology retrieval is near instant. You can search by time and date to select the incident or scroll through the list like scrolling through a page of text. VCR like controls provide the normal play, fast forward and rewind controls familiar to the user.

Fast access means fast response, so you can improve your efficiency and ability to deal with incidents. This can be particularly critical in retail applications, where the ability to circulate information, for example from the service counter to the security control room within seconds can be a vital element towards apprehending potential shoplifters.

Faster recording for longer
Digital systems do not rely on "time-lapse" recording to achieve extended record times which conventional video tapes require. The storage capacity of disk technology also far outperforms conventional tape systems in terms of capacity. A three hour analogue tape, regardless of the multiplexing that may be performed, holds about 540,000 image snapshots. Based on an average compressed frame size of about 15kbytes this approximates to about 8 gigabytes for a three hour tape. According to this it is easy to estimate that you need just under 2,000 gigabytes for a 31 day capacity. However improvements in compression and various other factors mean that you can expect around 300 to 400 gigabytes for a 31 day unit, and about half that for movement based recording. You can therefore achieve 31 day record time without the problem of changing tapes and at much higher record speeds, typically averaging one frame per second, than the extended 24 hour time lapse recording obtained from an analogue tape.

Event recording
Digital systems generally include record on movement or allow connection to external alarm devices such as passive infra-red detectors or retail tagging gates. This will enable you to filter unwanted information and make the most of your disk capacity. In these situations, a small amount of disk capacity, say 20 gigabytes, can go a long way, providing potentially many months worth of record history.

With some digital systems, there are options for pre-event recording, so you can capture the relevant few seconds leading up to and just following an event. Typical applications include retail tagging, where each gate activation records 10 seconds before and 10 seconds after an activation. In other specialist applications, such as bank raid alarm detection extended pre-event recording can be used to provide periods of up to 12 hours of real-time recorded video.

Movement only recording
Movement only recording typically uses software to discriminate movement within the camera field of view and is generally an integral component of the digital recorder. Thus extended periods of no activity, such as at nighttime, can be discarded thereby increasing the relevance of the video recorded and reducing operator search time. Software "masking" can be used to further improve filtering of unwanted data. Applications for this include screening tree leaf movement, or areas of public access from the effective field of view of the motion detection software. In most applications, record time can be at least doubled through the use of motion detection, but there may be instances where both continuous recording and movement based recording are required. Thus systems should be capable of simultaneously delivering both modes simultaneously.

Added intelligence
Software timers can be used to add flexibility to the recording patterns for example automatic disarming on specific cameras during office hours. Alternatively the timer can be used to automatically switch the record pattern from daytime recording to centralised monitoring via telephone at night. These kind of features are typical of the computer based systems, which often provide a greater number of features than the "black box" solutions.

Digital CCTV frequently forms part of a larger system through integration with the following:

:: Access control
:: Time and attendance
:: Building management
:: Industrial process monitoring
:: Electronic point of sale monitoring

Software based digital CCTV products through their flexibility make good candidates for integration with other non-visual systems. Verdant Technologies have successfully undertaken a number of projects to include our software and hardware into related products.

Remote access
Dialup
One of the most significant features to be offered by digital systems is remote access. This broadly allows global monitoring via telephone line, either digital or analogue, or local and wide area network to the live cameras and recorded images. As a verification tool remote access is a very powerful feature. It enables a site to switch between on-site and remote security as required, either automatically or for instance when the alarm panel is set as the last person leaves the premises. Response times to alarm activations can therefore be significantly improved. Dial out and first image display can be achieved in a few seconds from alarm activation, thus making it highly probable that an intruder can be detected and identified within seconds of an alarm activation.

Network
In the same manner that printers have been effectively shared through the use of local area networks. Cameras can also be shared between authorised users such as supervisors, security operators and facilities managers.

In addition there is a massive range of monitoring applications for which cameras are now being used ranging from health and safety requirements for hazardous equipment operation to weather conditions reporting at yacht marinas. Nearly all of these applications use network addressable cameras of one sort or another.

Pager/SMS
The use of pager and possibly SMS is an additional form of remote monitoring which is highly effective for mobile installers or self-monitored installations. In general the pager should be considered for applications where response time is important, since pagers are designed for use in time critical applications such as medical emergency call outs. While SMS services are available at relatively low cost, though the user’s mobile phone. SMS services are not guaranteed in the same way that Pager services are maintained. Whilst most of the time SMS response times are pretty fast, it is not very helpful to receive an SMS message three days after your premises have been ransacked.

Issues
Evidential Use
The use of digital images for evidential purposes has been a widely reported issue and views differ widely. It is generally accepted that one of the most important considerations is the audit trail. This applies to both analogue and digital recordings.

There is no one universal standard which states that digital images are not acceptable for use in court. The House of Lords Select Committee Science and Technology-Fifth report of 1998 can be reviewed online at address:

http://www.parliament.the-stationery-office.co.uk/pa/ld199798/ldselect/ldsctech/064v/st0501.htm

This provides a realistic and informed view of the issues and endorses the essential requirement for a verifiable audit trail whether applied to analogue or digital systems. According to the report recommendations there are no specific technical requirements to be met without which digital images would be automatically excluded. For example, there is no specific requirement for watermarking or other authentication process without which images would be automatically excluded. This is recommended on the basis that the courts themselves are best equipped to judge the validity or not of the evidence presented, and that it would be very difficult for the courts to specify the nature of the authentication technology, due to the fact that the technology would become rapidly outdated.

Security of data
With digital technology the requirements for data security are of prime concern.

Digital data, unlike analogue is easy to store, copy and distribute globally. Therefore in addition to the requirements for audit trail data handling it is essential to ensure that data is secure from both interception and tampering. If data falls into the wrong hands by interception through hacking into a CCTV network, then clearly there is a serious threat to site security.

It is therefore essential to take adequate steps to isolate access to public networks and provide a sufficient level of security to prevent unauthorized access. Where data is being transmitted via public networks, then the use of virtual private networks is strongly recommended to add protection against the risk of data interception.

Verdant Technologies provide consultation and support to assist with this growing problem.

Data protection Act
The data protection act of 1998 came into force on March 1st 2000 and has far reaching effects on the use of CCTV for non-domestic applications. Verdant technologies provide preliminary advise to customers seeking information about the need to register under the data protection act. Detailed information is also available at the following site:

http://www.dataprotection.gov.uk

Applications
:: Health and safety:
For hazardous equipment or swimming pool monitoring reduces staff costs for example, swimming pool lifeguards can monitor out of sight pool areas.

:: Small business systems:
Shops and office systems, replacement of existing analogue recording with digital CCTV

:: Retail Tagging systems
Pre-event recording to show a few seconds before and after each exit gate activation for fast and effective retail security

:: Electronic point of sale:
Till monitoring linked to transaction data with pre-event recording, ensures precise verification of each NO-SALE or other user specified transactions.

:: Remote monitoring:
24/7 response linked to one of our central monitoring partners provides fast visual verification of an alarm, eliminating police false alarm call outs.

:: Access control integration:
Positive Visual ID verification in high security applications or remote buildings

:: Airport Security:
Perimeter and car park control

:: Time and Attendance:
Pre-event recording ensures each card holder is visually verifiable, eliminating card substitution

:: Building management control:
Integration with fire alarm systems ensures rapid verification of reported exceptions

:: Transport Security:
Small rugged units for installation in bus, train and security vehicle applications

:: Wireless applications:
Wireless distribution of digital CCTV reduces cabling costs ideal for mobile and rapid deployment systems

:: ITU operations monitoring and recording:
Hospital applications include recording of operations for training purposes, with networked transmission to medical students.

:: Mobile systems:
Rapid deployment units for building site surveillance and police crowd control

The range of applications for CCTV are endless, however many applications require specialist hardware or software. Verdant technologies have an established track record of product development and integration with over 500 systems installed worldwide and are keen to work with both end users and system integrators to develop cost effective and efficient systems for the management of CCTV data.