PRINCIPLE CCTV

Installation Audio Video CCTV System

By Sarbini, S.Pd (SMK Muh 3 Yogyakarta)

THE MEANING OF CCTV

CCTV : Close Circuit Television : is camera spotter used to investigate or oversee a place which is considered prone from danger from

The function of camera is recording all activities so that they can minimize the risks, especially security and maintaining valuable assets.

INSTALLATION OF CCTV PURPOSE

Review, events in the area of supervision (the observed area) with environment .

Consist of :Lighting

Weather

Security

Detail image be demonstrated by the monitor.

Teknologi dan Rekayasa

1. CCTV ELEMENT SYSTEM

Six Conciderations design of CCTV :

The image environment.

The camera lens.

Transmission media.

Monitor.

Management of video signals and control equipment.

2. LIGHTING

Without the right light the camera can not perform the task with good image to give the desired

Key role in designing CCTV security applications is the lighting conditions in the area of interest, which will be determined, may be required if the addition of the light source, to what you want for your service.

Classification based camera lighting:

FULL VIDEO: Camera that can capture the image with the results of high accuracy

USABLE VIDEO (usable image): The camera that can capture events with the minimum level of information required.

If the lighting level is not sufficient for the given camera, the designer has two options:

Add light

Choosing a camera with a high senstivitas.

Three amount when considering levels of light:

Incident (light comes directly from all sources)

Reflected (reflected light from the camera to the events)

Image (part of the light reaching the image sensor).

The light spectrum

LIGHT QUALITY

LIGHT QUANTITY

Camera is able to see the light that can not be seen of men.

Light visible spectrum is actually made from red, orange, yellow, green, blue, indigo and purple.

Each color has wavelength in the range of 400 nm for violet to 700 nm.

In the color spectrum appears, the camera can see the colors in the near infra red scope (750 nm to 1150 nm) and infra red above 1150 nm. Wavelength color transition to this summer.

Special infra red camera to create images by using heat to change a light appears be reflected.

Because the camera quality is better to see the long waves, the lighting level in conditions of weak light appear, then see the camera image more effectively than the human eye.

Measure light Quantity (used photometer)

Two (2) other factors that will affect the amount of light that reach the image sensor, namely:

Transmissibility Lens

F Stop of the iris lens lowest (of widest)

LEVEL CALCULATING

Transmibility lens and the lowest f-stop must be determined

Simple calculation of the number of light sensors that reduce to images:

If = Ii X T 4 (f2)

(Where):

If = foot candle of light on the powerful image sensor Ii = foot candle of light on the strong lens T = transmibility lens (F2) = f-stop lens square

Example:

Landscape produce 5 ft, and focus the camera 0,9 and f-stop 1.4

Calculation

Ii = T 5 X 0,9 = 4.5A X (f2) a X 1,4 X 1,4) = 7,84If = 4,5 / 7.84If = 0,57

Because the result is less than one 1fc needed light to illuminate the image sensor (such as that written in the specification)

3. LENS

LENS

The lens is optically the components of the system that describes the image display include the size, shape and focus.

Principles lens

Lens Construction (add table)

Aberration Light Kromatic

FACTORS INTO THE QUALITY LENS EFFECT :

The Absorption Glass factorGlass low quality will absorb more light, and resulted in the availability of more low-light camera

Coating and PolishingThe quality of glass coating and polishing can improve the quality of the lens.

Mechanism Accuracy and reliability mechanisms that the glass snippet in the lens is important. Mechanisms tend to be low-quality settings is not carefully

BRASS LENS

Focus lens groupLens group variationsCompensaturation lens groupRelay Lens

The needs design of Brass Lens

Three factors determines image size :

Size format camera (1”, 2/3”, ½”, 1/3”).

Long focal length

Distance from the camera to the events.

Lens Placement

Lens selection

Step Lens Selection :

1. Identify the place of shooting, (to evaluate the lens, estimating wide / high vertical image capture).

2. Estimate the distance from the camera to the shot

3. Calculate the length of the lens focal

4. Estimate dimensional horizontal and vertical viewpoints critical area.

5. Determining the size of a critical area in the monitor view.

6. Select the lens close to the needs of the most

4. CAMERA

DETERMINES FACTORS QUALITY AND REABILITY CCTV SYSTEM

Resolution image sensor. Comparison of signal to noise. Automatic light compensation. Synchronization. Output signal. Environmental conditions and reliability

camera. Dimensions and weight.

5. MONITOR

Monitor criteria can be grouped in two category :

Electronic factors

Human interface factors