Ajhua Basic Knowledge of Video Surveillance System User Manual

Basic Knowledge of Video Surveillance System

CONTENT

Camera Introduction

System General Introduction

Recorder Introduction

Transmission Introduction

Display Introduction

VMS Introduction

Page3

Remote System – Topology

Legend

Coaxial Cable

Network Cable

Audio Cable

Data Cable

HDMI

HDCVI Recorder

HDCVI Camera

HDCVI PTZ

Pickup

Sensor

NVR

IP Camera

IP PTZ

Pickup

Button

Storage

Client

Controller

Management Platform

TV Wall

HDCVI Monitoring

IP Camera

IP Monitoring

Monitoring Center

Network

Product Selection Overview

1. Camera

Selection

2. Recorder Selection

4. Display Selection

5. VMS

Selection

3. Transmission

Selection

Camera

Accessories

Recorder

Accessories

Transmission

Accessories

Display

Accessories

VMS Accessories

CONTENT

Camera Introduction

CCTV General Introduction

Recorder Introduction

Transmission Introduction

Display Introduction

VMS Introduction

Camera Selection Overview

– The Installation Environment

• Angle of view, Focal length, DORI Distance, Light condition, Protection, etc.

– The Image Quality

• Lens, Sensor, Resolution, Frame rate, Image processing, etc.

– The Appearance

• Bullet, Dome, etc.

– The Interface

• Audio, Alarm, SD card, etc.

– The Intelligent Video Analysis

• IVS, Face detection, etc.

Camera Working Principle

• The working principle of camera is similar to the human vision system.

• It is mainly composed of three parts: the lens, the sensor, and the processor(DSP,ISP).

Human Vision System

Retina

(Feel the light and imaging)

ISP

DSP

Camera

Lens

(Cornea+Pupil+Lens)

Sensor

(Retina)

Processor

(Brain)

Brain

(Control, Analysis)

Cornea+Pupil+Lens

(Focus the light to retina)

Camera – Sensor Type

• Common sensor type: CMOS, CCD.

– CCD: image effect is better, but the power consumption is large, and wide dynamic performance is poor,

and the price is higher.

– CMOS: high integration, and price advantage is very obvious, and wide dynamic performance is good.

Sensor Type

Power

consumption

Illumination effect

Dynamic Range Price

CCD Large Better Bad High

CMOS Small Normal Better Economical

Camera – Lens Focal Length & Angle of View

Manually adjust the focal length adjustment ring. WIDE (W)<-->TELE (T)

It’s convenient for installation.

Fixed focal length camera always be installed in a fixed scene and the target object is

in a fixed area. (e.g. 8.5mm)

Zoom camera supply power for motorized lens

The focal length can be adjust

by motor remotely in operation menu to realize optical zoom in/ zoom out

Fixed Lens

Focal Length

Distance

f=2.8mm

WIDE (W)

f=3.5mm f=8mm f=30mm

TELE(T)

Varifocal Lens

Motorized Zoom Lens

Lens focal length can be searched in specifications:

E.g. The lens is motorized zoom lens, 7mm~35mm(35/7=5x optical zoom). When the focal length is 7mm, the Angle of view is H(horizontal) 38°, V(vertical) 22°. When the focal length is 35mm, the Angle of view is H(horizontal) 14°, V(vertical) 8°.

Why the FOV-H is different from FOV-V? Because the sensor is

rectangle, not a square.

Camera – Lens Focus

• The focus function can make the light focused to give the clear object imaging on the sensor.

Manually adjust the focus adjustment ring NEAR (N)<-->FAR (∞)

FAR too much NEAR too muchAppropriate Focus adjustment

Manual Focus

Motorized focus camera supply power for motorized focus lens The focus can be controlled

remotely in operation menu

Motorized Focus

Lens Focus mode can be searched in specifications:

Camera – Iris/Aperture

• The lens Iris can control the light which get through the lens so that images can be sharp, clear and correctly

exposed with good contrast and resolution. Generally speaking, the larger aperture opening means the

camera has better anti-shake performance.

OPEN too much CLOSE too muchAppropriate Iris adjustment

Manually adjust the Iris OPEN (O)<-->CLOSE (C)

Manual Iris

Auto iris camera supply power for auto Iris lens

The iris can be controlled automatically to adapt for different environment.

Auto Iris

Fixed Iris

The PFA (Predictive Focus Algorithm) adopts Dahua newly-developed focus algorithm, which ensures the camera image stays focused while zooming, and greatly improves user experience and enhances product value.

PFA

Camera – Different F-number Effect

• F-number = focal length / diameter of aperture.

– The smaller f-number, the larger aperture opening, the higher brightness, need less shutter time, and the

narrower depth of field, give the more contrast of the clear and vague.

F-number

Larger

Depth of field

Lower

Higher

Aperture opening

Smaller

Wider

Narrower

Lens F-number can be searched in specifications:

 Camera Video Performance

 Resolution

 DORI distance

 BLC/HLC/WDR

 White Balance

 ICR

 Low-light picture performance

 Protection

 …

Camera – Resolution

• A camera’s resolution is defined by the number of pixels in an image provided by an image sensor.

• The higher the resolution of the lens and sensor, the clearer the picture, the larger the output image size.

(Generally, the lens resolution should be larger than sensor so that the sensor performance won’t be

wasted.)

• Common resolution: CIF, D1, 960H, 1M (720P), 1.3M, 2M (1080P),3M, 4M, 4K.

Resolution

Pixels

960H

960

*576P (480N)

(720P)

1280*720

(1080P)

1920*1080

2688*1520

3840*2160

Camera – Resolution Comparison

• You can get more detailed information in a higher resolution picture even you

zoom in the picture in digital zoom mode.

– Digital zoom means enlarging the particular sections of a high-resolution image.

4K Camera 1080P Camera

Lens resolution can be searched in specifications:

Camera – DORI Distance

• The DORI distance is to define the camera Detection/ Observing/ Recognition/ Identifying capability. It’s useful in camera selection and installation guide.

If you want to realize

___________ the object

You need the min. object size in the picture

Detect

25PPM (Pixel Per Meter)

1 meter object in the picture correspond to at least 25 pixels to make the camera detect it. (E.g.

Realize motion detection to trigger the alarm)

Observe 63PPM

Recognize

125PPM

(E.g. Realize license plate recognition)

Identify

250PPM

(E.g. Realize face features identifying)

 E.g. A camera DORI distance is show as follows:

 The camera focal length can be adjusted from 2.7mm(W--WIDE) to 13.5mm(T--TELE).

 If you adjust the camera focal length as 2.7mm, the object in 46/18/9/5 meters away from the camera can be detected/observed/recognized/identified.

Camera – BLC/HLC/WDR

• Sometimes the environment is complex such as backlight environment, and the pictures do work

well. So we need do some compensation for these application scenario.

• We can select the compensation mode for different requirements: BLC for backlight environment, HLC for spotlight environment, WDR for a scene with a large difference between light and dark,

etc.

– Note: If we select the BLC mode of a camera, we can’t use HLC/WDR mode at the same time. The

function is switchable for different application scenarios.

Camera – BLC

• BLC (Back Light Compensation) technology is to enhance the picture brightness so that we can

see the object even in back light.

BLC off

BLC on

Camera – HLC

• HLC (High Light Compensation) can reduce the brightness of the entire to suppress the strong spot in the picture and use the additional illuminator to make the dark areas get compensation to get a clear image.

This function is often used to see the license plate number at night to suppress the car light effect.

HLC off HLC on

Camera – WDR (1/2)

• WDR (Wide Dynamic Range) cameras often incorporate an image sensor that takes different

exposures of a scene (e.g., a short exposure for very bright areas and long exposure for dark

areas) and combine them into one image, enabling objects in both bright and dark areas of a scene to be visible.

• WDR does not apply to scenes that move objects quickly.

WDR off

WDR on

Camera – WDR (2/2)

High

shutter speed

Ordinary

shutter speed

Synthetic effect

Combo

 120dB true WDR principle: take 2 pictures (a high light picture to see the dark object, a low light picture to

see the bright object) and combine them to 1 picture.

 140dB WDR camera takes 3 pictures , so we call it ultra WDR, which is better than 120dB true WDR.

Camera – DWDR

• DWDR (Digital WDR) is for the camera which don’t support true WDR. It’s achieved through the internal

DSP algorithm, mainly for the brightness curve to do some correction, the dark curve will be raised and the

bright curve down, such as the right part of the dotted line, the overall effect

• The effect of true WDR is better than DWDR.

Camera – BLC/HLC/WDR

• Sometimes the environment is complex such as backlight environment, and the pictures do work

well. So we need do some compensation for these application scenario.

• We can select the compensation mode for different requirements: BLC for backlight environment, HLC for spotlight environment, WDR for a scene with a large difference between light and dark,

etc.

– Note: If we select the BLC mode of a camera, we can’t use HLC/WDR mode at the same time. The

function is switchable for different application scenarios.

Camera – Color/Black and White

• The camera can be switched in Day/Night mode.

– In the day mode (color mode), the camera will give you a color picture.

– In the night mode (black and white mode), the environment is dark, the color effect is poor, so the camera will give

you the black and white picture to see the object clear.

– The camera DSP can switch the color/black and white mode automatically that the camera can judge whether it’s

day or night by analyzing the picture brightness or using the photo resistance to sense the environment brightness. Also we can switch the color/black and white mode manually in operation menu.

Analyze the picture brightness

using the photo resistance to sense

the environment brightness

Day(C

olor)

Night(Black

White)

Day/Night info can be searched in specifications:

Camera – ICR

• The sensor can sense the infrared light so that the picture will look red and purple. The camera can use the

ICR dual filter to solve the problem.

• The ICR dual filter consists of an Infrared Cut-off Removal filter and a full spectrum optical glass.

– Day: The infrared cut-off filter works, the IR light will be cut, so the sensor restores the true color.

– Night: The environment is dark, there’s little visible light, camera will switch into the black and white mode, The DSP

will remove the infrared cut-off filter and make full-spectrum optical glass work to pass the infrared light through so that the sensor takes full advantage of all the light, thus greatly improving the low-light performance.

ICR (color) ICR (night)

Camera – Low-light Performance

• In the night, Low illumination makes the camera difficult to focus, the image will be blurred and dark. To

solve the problem, we will take some method to improve camera low-light performance:

– Use a lens with large aperture, and use low speed electronic shutter to make more light pass through. – Use a big sensor and improve the sensor performance to sense more light.

– Use the AGC technology to amplify the electric signals.

• We will use the min. illumination value(Lux as unit) to judge the camera low-light performance. The lower

the Lux value, the better the camera's sensitivity.

Low-light info can be searched in specifications:

Camera – Starlight Technology

• The Starlight Technology can improve the camera low-light performance and make it deliver usable video

with minimal light. The starlight camera presents high quality colorful image with rich details even under

extreme lowlight environment (less than 0.01lux).

Snapshot by starlight Camera Photo taken by IPhone6S

Camera – Noise Reduction

• In preview, signal and noise exist at the same time. through the DNR (Digital Noise Reduction)

technology can inhibit the noise in the screen, then obtain better quality images.

– 2DNR works by analyzing individual frames of video, identifying algorithmically and correcting those

pixels that likely represent noise. 3DNR additionally analyzes the differences between successive frames

in order to adjust pixels and improve fidelity.

3DNR off 3DNR on

Camera – IR Camera

• IR camera means that the camera with built-in IR illuminator. When the environment is too dark, the

camera will turn on IR light automatically according to the photosensitive resistance feedback signal and

the camera will provide more details in the black and white mode.

– The luminescence conversion efficiency of IR is fixed. The Larger the IR angle, the shorter the IR distance. – E.g. The following image shows the effect of IR (when the IR distance is 100m).

IR info can be searched in specifications:

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