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CCTV Camera Introduction

It is important to understand the functionality of a CCTV camera; specifically how an image is first captured through a lens, processed through an image, and converted to a signal.

An example of a CCD image sensor is broken down by functionality. Although the video uses examples of CCD imagers, cameras may use a CMOS imager, increasingly common with IP cameras.

In addition, it is key to understand interlaced video functionality, interlaced standards, and composite video properties. 

There are many camera choices. It is a critical part of a video security system(VSS). If the camera is of poor quality your images will be of poor quality

Theory: the purpose of the camera is to convert a visual image into a series of electronic images. the information is then converted into an electronic signal that can be amplified and transmitted via a coaxial cable to the display link of VSS.

Imaging device( CCD): Charge-coupled device is a light-sensitive chip or image sensor used in scanners and a digital camera that converts light into video signal and delivers the signal to monitor .the AD converter(analog to digital converter) converts the analog signal into pixel values.

Sensitivity 0.1-0.01 lux

Resolution 380 to 580 tvl

Camera Lens:

A lens gathers available light and focuses the resulting image on the CCD chip of the camera. Lenses came in many sizes, focal lengths, and iris features

Camera Iris:

Iris opens and closes to control the amount of light passing through the CCD chip.

Video Picture:

A video picture whether it comes from your television set, a movie player or from your home camcorder is basically produced in the same way.A series of pictures are taken, b/n each of these pictures or frames is the balancing period. Odd and even fields are interlaced to complete a single frame. the lines in a frame contain the information needed to form a picture.

Real-time video = 60 field or 3 frames per second

Real-time

video =30 to 40 fields or 15 to 20 frames per second.

Interlacing video: means that instead of using a whole frame of visual information a frame is actually updated in parts over two slices of time.