Cctv systems
This presentation is the property of its rightful owner.
Sponsored Links
1 / 26

CCTV SYSTEMS PowerPoint PPT Presentation


  • 164 Views
  • Uploaded on
  • Presentation posted in: General

CCTV SYSTEMS. CCTV MONITORS. CCTV SYSTEMS. A monitor simply allows remote viewing of cameras in a CCTV system from a control room or other location. A video monitor should have a resolution that is at least as good as the camera’s resolution if not better. CCTV SYSTEMS.

Download Presentation

CCTV SYSTEMS

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Cctv systems

CCTV SYSTEMS

CCTV MONITORS


Cctv systems1

CCTV SYSTEMS

  • A monitor simply allows remote viewing of cameras in a CCTV system from a control room or other location.

  • A video monitor should have a resolution that is at least as good as the camera’s resolution if not better.


Cctv systems2

CCTV SYSTEMS

  • There is a saying that a surveillance system is only as good as its monitor.

  • There is another saying that a surveillance system is only as good as it’s cameras.

  • There is yet another saying that a surveillance system is only as good as the installer…


Cctv systems3

CCTV SYSTEMS

  • Recent advances in technology ensure that a customer can purchase a high quality system.

  • There are two types of security monitors: the older, bulky CRT monitor and the newer, sleeker LCD monitor.

  • The CRT monitor can be B/W or color, LCDs are color only.


Cctv systems4

CCTV SYSTEMS

  • CRT stands for Cathode Ray Tube.

  • It is the traditional box type of monitor or television.

  • The inside of a CRT monitor consists of three phosphor layers, one each for red, green, and blue colors.


Cctv systems5

CCTV SYSTEMS

  • When these layers are hit with electron beams, energy from the electrons is converted into light radiation, different compositions of the phosphor create different colors.


Cctv systems6

CCTV SYSTEMS

  • LCD stands for Liquid Crystal Display and it is actually not new.

  • It was first introduced in 1970 but for a long time it was inferior in image quality.

  • The inside of an LCD monitor consists of a liquid suspended between two glass or plastic panels.


Cctv systems7

CCTV SYSTEMS

  • The liquid crystals are naturally aligned to let light pass through except for when a current is applied, In this case, it blocks light, turning the affected area dark.

  • Different amounts of light are made to pass through the crystals by altering the amount of current used.

  • Red, green, and blue chambers inside the monitor produce color when varying amounts of current is passed through these chambers.


Cctv systems8

CCTV SYSTEMS

  • LCDs provide better image quality than CRTsthey produce a sharper, brighter picture because they can process CCTV signals at a higher resolution.

  • These monitors are also more responsive than CRTs, making them ideal for live video monitoring.

  • They are much lighter and less bulky than CRT monitors so they take up much less room.


Cctv systems9

CCTV SYSTEMS

  • LCDs also come in large sizes for multiple camera viewing situations.

  • A big advantage of CCTV LCDs over CRTs is that LCDs do not suffer from magnetic interference.


Cctv systems10

CCTV SYSTEMS

  • Speakers, for example, do not need to be shielded to be used in conjunction with the monitor.

  • Another advantage of a CCTV LCD is screen flicker is not an issue.

  • With CRT monitors, low refresh rates leads to screen flicker, an annoying occurrence.


Cctv systems11

CCTV SYSTEMS

  • Despite all these advantages, there are some disadvantages to a CCTV LCD, One is the contrast ratio.

  • It is easier to produce higher contrast in CRT monitors because the electron gun can be turned off for true blacks.

  • In an LCD the backlight is always on so a certain amount of light will always show through, Because of this, buyers should be aware of an LCD monitor’s contrast ratio,an effective ratio is 400:1.


Cctv systems12

CCTV SYSTEMS

  • Another drawback is LCD monitors sometimes generate dead pixels, or areas of the screen that remain black because they no longer function.

  • If the monitor is under warranty, most manufacturers will repair dead pixels, but this leads to system downtime.


Cctv systems13

CCTV SYSTEMS

  • An important distinction should be made between CCTV LCD monitors and regular LCD monitors.

  • CCTV LCD monitors have a processing scaler, which is a device designed to display the best possible picture from a security camera by up converting the signal.

  • CCTV LCD monitors can cost as much as two to three times more than a regular LCD monitor.


Cctv systems14

CCTV SYSTEMS

  • The viewing angle is a limiting factor of LCD monitors.

  • LCDs typically come with VGA, HDMI, composite and BNC connections as well as audio connections.


Cctv systems15

CCTV SYSTEMS

  • It should be noted that any time we use the word monitor it means there is no TV tuner in it.

  • Monitors, both CRT and LCDs have controls for contrast, brightness etc., on CRTs the adjustment knobs are on the monitor, for LCDs it is an on screen menu.


Cctv systems16

CCTV SYSTEMS

  • Monochrome CRT monitors are typically deployed in CCTV systems over color CRTs.

  • Monochrome is considered a better choice because of it’s clarity and resolution, monochrome is not the same as black and white.

  • Monochrome is one color and the absence of that color.


Cctv systems17

CCTV SYSTEMS

  • Monitor sizes are measured diagonally, CRT monitors have an aspect ratio of 4:3and LCDs monitors are typically 16:9 which is the widescreen standard.


Cctv systems18

CCTV SYSTEMS

  • All CRT’s use the NTSC (National TV standards committee) standard which is the analog standard.

  • LCDs use the ATSC (Advanced TV systems committee) which is the digital standard, most LCDs also support the NTSC standard.

  • Most CRT monitors will also support the PAL (Phase Alternating Line) European standard.


Cctv systems19

CCTV SYSTEMS

  • Another thing to consider is the TVL (television lines) of the CRT monitors.

  • TVL is a standard used by cameras as well.

  • 450 TVL and below is considered a standard resolution where approximately 500 TVL is closer to be a HD (high definition) standard.


Cctv systems20

CCTV SYSTEMS

  • LCD monitors will support all TVL standards however resolution for flat screens are 720P, 1080i and 1080P.

CAN YOU TELL THE DIFFERENCE?

1080i1080P


Cctv systems21

CCTV SYSTEMS

  • What does the “I” and the “P” in 1080i and 1080P stand for?

THE “i” STANDS FOR INTERLACED AND THE “P” STANDS FOR PROGRESSIVE SCANNING, INTERLACED SCANNING HAS A TENDENCY TO BLUR DURING ACTION SEQUENCES, THIS DOESN’T HAPPEN IN PROGRESSIVE SCANNING.


Cctv systems22

CCTV SYSTEMS

  • Cameras use impedance to synchronize signaling when connecting monitors and other inline equipment to the output of the camera.

  • Connecting two monitors to a single camera using a T-connector will not work properly.


Cctv systems23

CCTV SYSTEMS

  • Assume that both monitors are terminating monitors, they both only have 75 ohm input jacks.

  • If you simply connect them both to the same camera you will experience negative effects, such as signal fading, alternating contrast and even lost video framing.


Cctv systems24

CCTV SYSTEMS

  • Both present 75 ohms of impedance and thus signaling is affected, the correct way to connect two monitors to the same video source is to use a video loop through.

  • Most terminating monitors have a switch that toggles between 75 ohms and zero ohms.

  • This switch must be turned to the off position (zero ohms) at the first monitor and 75 ohms at the second.


Cctv systems25

CCTV SYSTEMS

  • The output of the camera is connected to the first monitor and then looped through to the second monitor.

  • The second monitor provides the proper 75 ohm termination.

  • Some monitors are auto-terminating, they sense whether a signal is being looped or not.


  • Login