Search
Home
Home
Home > Products > Accessories > Helpful Tips

Helpful CCTV Tips

Camera back focus adjustment ensures that a camera's image remains in focus during changing lighting conditions. This is a common problem in CCTV installations where one sees a sharp image during daylight but a blur at night. During bright sunlight, the lens iris is closed and the depth of field very wide. When the light level drops, the Iris opens and the depth of field decreases. To reach the optimum focus, the camera needs to be back focused with the lens’s iris fully opened. Proper back-focus adjustment also holds true for zoom lenses which need to be properly adjusted to hold focus through the zoom range.

 

 


 
Features CCTV Monitors TV with Video-In
Resolution 5000-1000TVL 250-3000TVL
Housing

Metal Housings with protection from the
environment and electro-magnetic interference

Plastic Housing
Connectors Metal BNC Plastic RCA
Form Factor Square shape: Easily stackable Rounded shape: Non-stackable

 

 

 
PC-BASED DVR
  • Use of existing IT infrastructure for remote monitoring and backup
  • Maintenance by company's IT technician
  • Upgradable Computer Hardware (HDD size, Processor
    Speed, Graphics etc)
  • Upgradable DVR channels (additional DVR cards)
  • Easy availability of spare parts
  • Familiarity of Windows Software
  • Stability of Win2K's NTFS file system
STAND-ALONE DVR
  • Ideal for non-PC-literate users
  • Fast Boot Time
  • Similar in function to a VCR
  • 12VDC or 220VAC Operation
  • Can be used for mobile applications

 

 
The CCTV digital age has really arrived

More and more people are moving to DIGITAL BASED CCTV Systems over the conventional analog VCR based systems. The benefits of using a digital system, is that it allows the user to replace their switching unit, monitor and time-lapse recorder with one centralized system, which they can access and control from several locations. Because the system is automated, one does not have to swop or replace any video cassette tapes, allowing minimum intervention from the system controller.

These systems can record video images on the HDD, depending on capacity, for several weeks. A digital system allows the user to instantly retrieve relevant data. There is no longer a need for screening through hours of video tape to find a single frame of video. Data is stored in a database which can be searched by camera, time, date, alarm-activation or motion. This saves the user time in identifying the target.

Even at the most basic level digital video images are superior to video recorded on analog systems. Sharp, crisp images are stored which can be viewed over and over again without image deterioration.

Yet another advantage of digital systems is their flexibility of recording modes. Recording can be done by schedule (ie. time or date), alarm activation or via smart motion detection.
  • Faster retrieval times - No more plodding through hours and hours of videotape. Utilising digital CCTV, users can instantly retrieve video. Users can rapidly search events by time, date, location and camera.
  • Less storage space required - Users may set the system to record
    when motion or other pre-defined events are detected - so there's no
    wasted "dead taping". Video is then compressed and efficiently stored
    to a PC's hard drive.
  • Archiving - Important information can be archived to FDD, HDD, CD-R
    or DVD for later retrieval.
  • Higher image quality - Digital CCTV provides unbeatable quality.
    Digital video can be easily enhanced and copied over and over without
    losing its original quality.
  • Better quality - Digital Video Recording provides much sharper better quality images to aid in evidence and image recognition.
  • No Tapes - with analog systems tapes need to be replaced regularly,
    but digital storage media has an almost unlimited lifetime.
  • Immune to noise - Digital systems are less affected by noise than analog systems.
  • Transmit and retrieve stored data - Across town or across the world,
    video images can be remotely viewed, easily saved, retrieved, displayed, copied, printed, faxed and e-mailed.
  • Less Obsolescence - Most systems’ software is upgradeable which
    extends the systems’ lifetime.
  • No Routine Maintenance Required - Other than DVR’s, VCR's are
    required to be serviced once a year for reliable operation.
 
A. Purpose of the CCTV System
  • Covert
  • Access Control
  • Event Recording
  • After Hours Monitoring
  • Crime Prevention
  • Industrial Monitoring
  • Improved Security
  • Industrial Safety
  • Management Tool
  • Vehicle or mobile
  • Post-Event Evidence Tool
  • Process Control
B. Budget
 
C. Cameras
  • B/W, Colour or Day/Night
  • Covert or Visible
  • Auto Iris (outdoors) or Manual Iris (stable lighting conditions)
  • Areas to be covered (by cameras)
  • Fixed or PTZ cameras
  • Location & purpose of each camera
  • Distance from the camera to the subject/scene
  • Angle of view required
  • Decide if camera housing needs to be used
  • Type of mounting required i.e pole, wall, ceiling, corner etc.
D. Power
  • Availability during required times of operation
  • Position in respect to camera position
  • Localize or centralize power to cameras i.e. power each camera individually or altogether from centralised place such as control room
  • Size of PSU is relevant to the number of cameras to be used off it
  • 12VDC or 220VAC operated equipment (i.e mobile applications)
  • Use of UPS?
E. Transmission of Video Signal
  • Via cable, i.e RG59U, Power-Ax, Twisted-Pair, Fiber-Optic or Wireless
  • Distance of signal transmission
  • Obstacles i.e sharp bends, high voltage equipment, roads/boundaries, different buildings
  • Protection of cabling against environment
F. Lighting
  • Amount of lighting during day & night
  • Direction of sun's position during day
  • Avoid placing cameras directly into sunlight
  • Constant or variable lighting conditions
  • Use of Infra-Red Illuminators/Cameras
  • Additional lighting needed?
  • Type of light source i.e flourescent, sodium, incandescent,
    tungsten, sunlight, moonlight, starlight, halogen, mercury vapour etc.
G. Environment
  • Indoor or Outdoor
  • Marine/Coastal Area
  • Vandal-Resistant
  • Variation in temperature
  • Need for Wiper/Washer Camera Housing
  • Intrinsically Safe
  • Highly Corrosive
  • Industrial
  • Hotel/Entertainment Industry
H. Monitoring and Recording Location
  • A central location to cut down on long cable runs
  • Sufficient clean power available with 24 hour operation
  • Safely secured in event of robbery or tampering by internal staff
  • Sufficient physical space available for equipment and the maintenance thereof
  • Use of recessed or reflective lighting with dimming control to prevent monitor glare
  • Monitor/s should be placed directly in line-of-sight of the operator in the seated position (no less than 1,5m away)
  • No more than 5 monitors per operator
  • Requirement for additional remote monitors in a seperate area?
I. Unmanned or Manned CCTV Site
  • If analog system, availability of staff to change tapes
  • PTZ cameras require an operator to be totally effective
J. Digital or Analog Recording
 
L. Communication Infrastructure and Bandwidth
  • Availability of ISDN, PSTN, DSL or leased line circuits
  • TCP/IP Routers
  • Bandwidth requirements for amount of cameras and frame rates required
  • Wireless or fixed network
M. Any Existing CCTV
  • Integration with existing speed domes, matrix or keyboard controller
  • Use of existing cabling?
 
A. Camera Power
  1. Use only regulated power supplies, the tolerance should be within 5% of the required voltage.
  2. Ensure at least 40% spare capacity per power supply to prevent overheating and voltage loss.
  3. Use power cable of a suitable thickness
  4. Beware of voltage drops over long distance runs
  5. Beware of polarity when connecting the power supply to a camera
  6. Ensure proper cooling or ventilation for power supplies
  7. Avoid operation of CCTV equipment on the same power circuit as elevators, compressors, generators or any large motors.
B. Cabling
  1. Avoid running video cable parallel to AC power cables, especially those carrying high current.
  2. RG59U Co-Ax runs should not exceed 200m for colour and 300m for B/W
  3. Avoid sharp bends when cabling
  4. Avoid cable joins and using BNC barrels
  5. Avoid over-tightening cable-ties
  6. Ensure use of proper co-ax wire-stripping and crimping tools
  7. Ensure BNC Connectors are properly crimped
  8. Use Rubber BNC Boots after crimping to protect crimped area and bend radius
  9. Mark or label camera and data signal cables
  10. Outdoor cable runs should be housed in UV-proof conduit
  11. In lightning prone areas, install surge protection devices
C. Camera Installation
  1. Test all equipment before installation. Therefore equipment can be replaced before arrival on-site if needed.
  2. Ensure the mounting brackets of outdoor speed domes are properly sealed to prevent condensation in the camera housing.
  3. Use EIA rated RS232/422/485 or CAT-5 cabling for speed dome or PTZ communication.
  4. Ensure sufficent space for camera, lens and connectors when choosing a camera housing.
  5. Avoid direct sunlight on equipment as it raises the temperature of the equipment.
  6. Position cameras out of reach of vandals or 'curious' people.
  7. Mount good quality mounting brackets in a stable location to avoid unstable or vibrating images caused by vibration or wind.
  8. CS Mount cameras placed inside, at industrial or dusty/damp installations should be placed into outdoor camera housings.
  9. Avoid installing cameras too high above the subject thus preventing 'top-of-head' video images
  10. Ensure camera mounting poles are mechanically secure to avoid vibration on camera images
  11. Before connecting power, ensure the supply is 12VDC regulated.
D. Time Lapse VCR Considerations
  1. Time Lapse VCR Considerations
  2. Regular servicing of your VCR , will ensure continued operation and quality of recordings.
  3. Use only high quality 'branded' tapes
  4. Replace tapes after being used 12 times.
  5. Ensure Time Lapse VCR is suitably hidden in event of a robbery
  6. Before reviewing a video tape for evidence, make a copy and review the copy. This ensures the the quality of the original is preserved, especially when starting, stopping and pausing the tape.
E. Wireless Video Transmission
  1. For outdoor use, transmitter and receiver must be in line-of-sight.
  2. Determine any possible sources of interference, i.e. overhead powerlines, wireless LAN networks, transformers, other transmitters or any other power generating system in close
    proximity to the transmitter or receiver.
  3. Avoid trees in the transmission path, as brances can cause interference.
  4. Ensure proper alignment between transmitter and receiver.
  5. Beware of lightning. Transmitters are often placed on high masts/roofs, which make them prone to lightning.
  6. Poor weather such as heavy fog and rain can affect transmission.
F. Digital Video Recorder Considerations
  1. It is recommended to connect your DVR and cameras to an uninterruptable PSU (UPS)
  2. Ensure 1Vp-p video input levels from cameras (not lower or higher)
  3. Turn off camera AGC
  4. Ensure DVR is suitably secure or hidden in event of a robbery
  5. Avoid Win98/ME as an operating system, Win2K is the most stable for PC-based DVRs
  6. For PC-based DVRs, regular HDD defragmentation is recommended if DVR is used for other user applications. (Not necessary if PC is dedicated to DVR.)
  7. Ensure enough RAM so that the recording does not get interrupted.
  8. Recording should be on different hard drive to that of the operating system and recording software.
 

One of the biggest issues in the design and usage of any Closed Circuit Television System is the usable images or video footage that one can utilise during or after an event.

There are obviously several factors that come into play when determining this. Factors include quality of installation, video recording resolution, frame rate, environmental conditions, CCD resolution and sensitivity. When designing a CCTV system it is important to have focused cameras at all entry and exit points. Any individuals or vehicles will need to pass through these points to access or exit the area under surveillance. All CCTV camera positions have an application or role. These include monitoring and detection, as well as recognition and identification.

As an aid for the CCTV installer the UK Home Office has published a guideline in regard to identifying individuals or vehicles. By using this guideline you will be able to achieve the camera objectives your installation requires.

As an aid for the CCTV installer the UK Home Office has published a guideline in regard to identifying individuals or vehicles. By using this guideline you will be able to achieve the camera objectives your installation requires.

 

Another key aspect of CCTV Systems is installing cameras that provide usable images in the required lighting conditions. This ranges in extreme from a brightly lit supermarket to a parking lot, lit only by the moon. Camera manufacturers normally provide minimum illumination specifications for their cameras in the best case scenario. Factors that effect the performance of CCTV camera include the following.

  • Lens Aperture - Lenses in fact allow only a small percentage of light to reach the camera’s sensor, this is further effected by the
    aperture of the lens to be used. An F1.0 lens allows 20%, an F1.4 allows 10% and F2.0 only allows 5% passed.
  • Lens Quality - The quality of the lens determines the efficiency of the light that is transmitted through the lens. Your image quality will be much better when using an aspeherical lens, inplace of a standard lens which will not handled the light as efficiently.
  • Camera Housing - The amount of light reaching a camera’s sensor can be reduced by approx 30% when passing through a
    housing’s glass window.
  • Surface Reflection - Different surfaces have varying percentages of reflectance. Therefore it is better for a camera’s sensitivity to be focused on a white washed wall (60%) than an empty tarred parking lot (5%). Most manufacturers provide figures using the highest reflectance target surface (90%).
  • Spectral Response - Camera sensors and lenses react differently under differing light spectrums.

To summarise in many camera installations one actually requires external lighting in the vicinity of 10 ~ 40 lux to provide a usable colour picture from the camera.