Vivotek IP Surveillance Installation guide

Welcome to
Planet VIVOTEK
About VIVOTEK:
VIVOTEK Inc., founded in 2000, has quickly taken its place as a leading manufacturer
in the IP surveillance industry. VIVOTEK specializes in the integration of audio-visual
components into network operation. Using sophisticated codec technologies, VIVOTEK's
innovative R&D team develops a wide range of multimedia communication products.
In 2006, VIVOTEK became a publicly traded company in the Taiwan Stock Exchange
offering sales, support, and other services in over 70 countries through a wide network of
distributors and system integrators.

Table of Contents
Chap.1 IP Surveillance Overview 01
1.1 Overview 01
1.2 Network Cameras 01
1.2.1 Introduction 01
1.2.2 Camera Types 03
1.3 Video Servers 04
1.4 Network Video Recorders 05
1.5 Central Management Software 05
1.6 Evolution of Video Surveillance 06
Chap.2 Lens and Image Sensor Technology 07
2.1 Lens 07
2.1.1 Focal Length 07
2.1.2 Iris 08
2.1.3 Lens Mount Types 09
2.2 Image Sensor 11
2.2.1 Sensor Types 11
2.2.2 Resolutions 11
2.2.3 Sensor Scan Modes 13
2.2.4 Wide Dynamic Range 14
2.3 Lens and Image Sensor Considerations 14
2.3.1 Lens Form Factors for Image Sensor 14
2.3.2 View Angle 15
2.3.3 Day and Night 15
Chap.3 Video and Audio Compression 19
3.1 Video Compression 19
3.1.1 MJPEG 19
3.1.2 MPEG-4 20
3.1.3 H.264 21
3.2 Audio Compression 22
3.2.1 G.711 22
3.2.2 AMR 22
3.3.3 AAC 22
3.3 Video and Audio Streaming 23
3.3.1 Multiple Streams 23
3.3.2 Two-way Audio 23

Table of Contents
Chap.4 IP Network 25
4.1 Network Types 25
4.2 Network Devices 25
4.3 IP Address 26
4.4 Network Protocols 27
4.4.1 Device Connection 27
4.4.2 Transmission Protocols 30
4.4.3 Video Transmission Methods 30
 4.4.4 EventNotication 31
4.4.5 Timing Correction 31
4.4.6 Video Quality Control 31
4.5 Wireless Networks 32
4.5.1 WiFi 32
4.5.2 3GPP 32
4.5.3 WiMAX 32
4.6 Security 33
4.6.1 IP Filtering 33
4.6.2 Username and Password 33
4.6.3 Security Protocols 33
4.6.4 Security Wireless Transmission 34
4.7 PoE 35
Chap.5 Camera Housing and Mounting 37
5.1 Housing 37
5.1.1 Vandal-proof 37
5.1.2 Weather-proof 37
5.1.3 Covering 38
5.2 Mounting 39
5.3 Scanner 40
Chap.6 Bandwidth and Storage 41
6.1 Bandwidth Management 41
6.1.1 Assessing Demands 41
6.1.2 Calculation 41
6.2 Storage 41
6.2.1 Assessing Demands 41
6.2.2 Storage Media 42
6.3 Redundancy 43
6.3.1 Cables 43
6.3.2 RAID 43

Table of Contents
Chap.7 Video Management 45
7.1 Video Management Platforms 45
7.1.1 PC-based 45
7.1.2 NVR-based 46
7.2 Basic Features of Software 47
7.2.1 Monitoring 47
7.2.2 Recording 48
7.2.3 Playback 48
7.2.4 Management 49
7.3 Advanced Features 49
7.3.1 E-map 49
7.3.2 Auto-backup 49
7.3.3 Failure Report 49
7.4 Digital I/O Devices 49
7.4.1 Digitial Input Devices 49
7.4.2 Digital Output Devices 50
7.5 Managing Large Systems 50
Chap.8 Applications 51
Chap.9 System Design 53
9.1 Identifying Customer Needs 53
9.1.1 Viewing Considerations 53
9.1.2 Environmental Considerations 54
9.2 System Planning 58
9.2.1 Camera Considerations 58
9.2.2 Hardware Considerations 58
9.2.3 Software Considerations 58
9.3 Installation and Checks 58
9.3.1 On-site Installation 58
9.3.2 Post-installation Checks 58
9.4 Operational Training 59
9.5 System Maintenance 60
Chap.10 Intelligent Video Systems 61
10.1 Introduction 61
10.2 Architecture 61
10.2.1 Centralized Platform 61
10.2.2 Distributed Platform 62
10.3 Advantages of Distributed Architecture 63
10.4 Detection 63
10.4.1 Tamper Detection 63
10.4.2 Intelligent Motion Detection 64
10.4.3 Loitering Detection 65
10.4.4 License Plate Recognition 65
10.4.5 People Counting 66
Glossary 67

Chap.1 IP Surveillance Overview
1
1.1 Overview
Increasing penetration of the Internet and the development of innovative technologies have encouraged rapid
growth of the IP surveillance industry, driving changes in the video surveillance market. It is expected that IP
surveillance will be dominating the video surveillance market in the near future, with network cameras and video
servers being major trends.
An IP surveillance digitizes video streams and transmits them over networks, allowing users to view and manage
the video and images remotely with a networked device, such as a PC, anytime and anywhere. Key components
of an IP surveillance system consist of network cameras, video servers, network video recorders and central
management software. VIVOTEK provides a full range of products mentioned above to help customers build a
reliable and high performance IP surveillance system that meets their needs.
IPsurveillanceproductsarebeingusedinavarietyofapplicationelds,whichgenerallyfallintothefollowingfour
categories:
●Professional applications: transportation, government, industrial, construction, health care, etc.
●SMB applications: banking, education, retailing, recreation, etc.
●Home applications: residential surveillance, digital home, etc.
●3GPP applications: mobile surveillance, elder care, baby or pet viewing, etc.
1.2 Network Cameras
1.2.1 Introduction
A network camera, also known as Internet camera, IP camera or Internet video camera, transmits live digital video
over an Ethernet network to back-end devices such as a PC or 3G phone. With a dedicated IP address, a built-in
web server and audio/video streaming protocols, it can work independently for real-time monitoring.
Images from network cameras can be viewed with a web browser such as Internet Explore, Firefox, Mozilla and
Opera, enabling customers to perform live viewing on different networked devices. In addition, customers can
control and manage multiple cameras at the same time in any places where network connection is available.
Therefore, an IP surveillance system is easier and more convenient to use compared with a CCTV system.
IP Surveillance Overview
Chap.1

Chap.1 IP Surveillance Overview
2
A network camera mainly consists of a lens, an image sensor, an image processor, a video compression SoC
(System on Chip) and an Ethernet chip that offers network connectivity for data transmission (Figure 1.2).
When light passes through the lens to the sensor, it is converted to digital signals and then processed by a built-in
digital signal processor. The processed video data is then compressed by a multimedia SoC to achieve a smaller
data size for optimal transmission. Finally, the video images are sent through the Internet to back-end devices to
allow for viewing and storage. Apart from video compression, the SoC is built with a RISC CPU for processing
system and network data.
The general interface of a network camera includes a power cord socket, an Ethernet socket, audio I/O ports and
digital I/O ports (Figure 1.3).
Router
Lens Image
Sensor
DSP for Image
Processing
SoC for
Video/audio
Compression
Flash
ROM DRAM
WLAN or
Ethernet/PoE LAN/Internet
Power Cord
Socket
Ethernet 10/100
RJ45 Socket
Indented Reset
Button
General I/O
Terminal Block
Audio Out
External/Internal
MIC Switch
Microphone In
Status LED
SD/SDHC
Card Slot
Figure 1.3 General interface of network camera
Figure 1.2 Network camera composition
Figure 1.1 Network camera connection

Chap.1 IP Surveillance Overview
3
In addition to a full-range IP surveillance product lineup, VIVOTEK has achieved competitive advantages over
other rivals in terms of multimedia SoC design, EE & ME integration and multimedia SDK. With these capabilities,
VIVOTEK is able to provide highly integrated products with superior image quality, comprehensive customer
services and versatile application solutions.
1.2.2 Camera Types
Generally,networkcamerascanbedividedintofourtypesfordifferentapplications,includingxed,pan/tilt/zoom,
xeddomeandspeeddome.
Fixed Type
A fixed network camera points in a fixed direction to monitor a specific area, such as hallways, staircases or
corridors. Because people can be aware of the camera’s shooting direction, in some cases, it can deter vandalism
and crimes.
AxednetworkcamerausuallycomeswithaRS-232/422/485interfacethatconnectsthecamerastoapan/tilt
scanner for wider coverage.
Manyxednetworkcameras has exchangeable C/CS-mountlensdesign,givinguserstheability to change the
lens to adapt for different monitoring conditions. For more information on C/CS-mount, please refer to Chapter 2.
Figure 1.4 Fixed network camera
Figure 1.5 PTZ network camera
Pan/Tilt/Zoom Type
Capableofchangingshootingdirectionhorizontallyandverticallytoachieveawideeldofview,apan/tiltnetwork
camera is used in many spacious areas, such as lobbies or parking lots.
Some pan/tilt network cameras are integrated with zoom capability so as to provide close-up images of distant
objects. Users can easily control PTZ functions through a web browser.

Chap.1 IP Surveillance Overview
4
Figure 1.8 Video server
1.3 Video Servers
A video server is a device that converts analog signals to digital, allowing users to migrate to a digital surveillance
system without replacing existing CCTV systems.
A video server mainly includes a compression chip and an Ethernet chip, with two main types available: one port or
four ports.
Speed Dome Type
Comparedwithxeddometype,aspeeddomenetworkcameraisintegratedwithpan,tiltandzoomcapabilities,
enablingafargreatereldofview.Withahighzoomcapability,imagestabilizationand360-degreeendlesspan,a
speed dome camera is mainly used for professional applications, such as airports, banks or city security.
Fixed Dome Type
A fixed dome network camera, mostly designed for indoor surveillance, has a housing to make the object of
interest less aware of where the camera is pointing at. With a 3-axis mechanism, images can remain in an upright
orientationwhenitisinstalledeitheragainstthewallorontheceiling.Furthermore,thedesignofaxeddome
networkcameracanbettertinwiththe decor.
Axeddomenetworkcameracanbefurnishedwithaweather-orvandal-proofhousingforoutdoorapplications.
Figure 1.7 Speed dome network camera
Figure 1.6 Fixed dome network camera

Chap.1 IP Surveillance Overview
5
1.5 Central Management Software
Central management software, often provided by the camera vendors or individual software vendors, enables
customers to manage and control cameras from remote site. Typically, central management software is windows-
based, and thus can be installed in almost any PC.
Central management software employs client-server architecture where server software,client viewing software
and playback software is installed in separate PCs. Customers can perform live viewing, event-triggered recording
or playback on the client PC while managing cameras and performing constant recording with the server PC. Each
server PC can be scaled up to include several subordinate server PCs, and thus expand the number of managed
cameras.
VIVOTEK ST7501 central management software works seamlessly with VIVOTEK’s full-range network cameras
and video servers, helping customers establish a robust, flexible and efficient platform for centralized video
management.
Figure 1.10 Central management software
1.4 Network Video Recorders
An NVR (Network Video Recorder) is an IP-based recorder that operates independently from a PC or other
operation systems. Aimed to store digital video streams from network cameras, an NVR is usually incorporated
with a large-volume hard disk to allow for a long period of recording.
An NVR differs from a traditional DVR in its network connectivity, which allows digital data to be transmitted to other
networked devices over the Internet. Another difference is that an NVR can be directly connected to a network
camera while a DVR is usually be connected to an analog camera.
VIVOTEK’sNR7401helpsyoubuildahigh-efciencysurveillancesystem,whereyoucansimultaneouslyrecord,
monitor and manage video data through the Internet. NR7401 works seamlessly with all VIVOTEK network
cameras.
Figure 1.9 Network video recorder

Chap.1 IP Surveillance Overview
6
1.6 Evolution of Video Surveillance
For two decades of evolution, video surveillance has progressed from fully analog to fully digital. The development
ofsurveillancesystemsissegmentedintothreeperiods,knownastherst,secondandthirdgeneration.
The first-generation surveillance system consists of the use of analog CCTV cameras, multiplexers, analog
monitors and VCRs. Camera images are transmitted via coaxial cables and stored in VCR cassettes. Due to
limited storage capacity, the cassettes must be replaced frequently for a long period of recording.
The early 1990s saw the emergence of the second-generation surveillance system, which is composed of CCTV
cameras, DVRs and digital monitors. Analog camera images are digitized and stored in DVRs. The replacement
ofVCRsbyDVRsgivesusersmoreexibilityindataviewingandstorage.Around2005,demandfornetwork-
enabled DVR picked up, and pure network-enabled NVRs were introduced. NVRs provide remote data access and
management capability.
The third-generation surveillance system, also known as IP surveillance, appeared in early 2000. The surveillance
system uses network cameras and takes full advantage of the TCP/IP Internet. Users can remotely control, monitor
and record live video (Figure 1.11).
Advantages of IP Surveillance
● Remote monitoring/storage
Since video data can be transmitted to remote networked devices over Ethernet networks, users can view camera
images in any place where IP network connection is available.
● Cost efciency
VideosurveillancesystemscanleverageexistingIPnetworkinfrastructure,signicantlyreducingoverallinstallation
costs.
● High scalability
Adding new network cameras or other networked devices in an IP surveillance system is easy by simply connecting
them to a router.
● Superior image quality
Network cameras provide high image quality; many of them even offer megapixel resolutions. In addition, IP
surveillance has no signal degradation problems during transmission, and thus can ensure steady image quality.
PC with Video
Management Software
VS7100
LAN
LAN
LAN
LAN
Internet
Analog
Camera
Coaxial Cable
VIVOTEK Video Server
VIVOTEK Network Camera
VIVOTEK Network
Video Recorder
video
AudioOut AudioIn
VS7100
LAN
Analog
Camera
Coaxial Cable
video
AudioOut AudioIn
NVR
Figure 1.11 IP surveillance system architecture

Chap.2 Lens and Image Sensor Technology
7
Lens and Image Sensor Technology
2.1 Lens
The generation of a high quality image is decided by many factors including light source of the environment, lens,
sensor, compression engine, etc. However, for camera itself, a lens is the most fundamental component that
rstlydecidesiftheoutputofthequalityisgoodornot.Inthesecurityindustry,becausetheuseofcameradiffers,
especiallyxedtypewithC/CSmount,systeminstallersthemselveshavetoselectandpurchasealensttingtheir
specicneeds.
2.1.1 Focal Length
Focal length is the distance between the sensor and secondary principal point of the lens.
Chap.2
Theshorterthefocallength,thewidereldofviewitoffersandhigherlevelofdistortionitmaycause.Incontrast,
thelongerthefocallength,thesmallerviewingangleandeldofobjectithas.
Focal Length
Focal Point/
Image Sensor
Forward Principal Point
Backward Principal Point
Figure 2.1 Focal length

Chap.2 Lens and Image Sensor Technology
8
Figure 2.2 shows image distortion caused by a shorter focal length and the telephoto effect resulting from a longer
focal length.
2.1.2 Iris
Iris can control the amount of light entering the lens during exposure. Iris is one of the most important elements for
light sensitivity, along with aperture, shutter time, sensor, and gain.
Lenses include the following types:
• Fixed lens: the focal length cannot be changed.
• Vari-focal lens: thefocallength(eldofview)canbemanuallyadjusted;.Themostcommonvari-focal 
lens is 3.5 - 8 mm.
• Zoom lens: a kind of vari-focal lens with motorized mechanism to adjust its focal length. Generally, AF
(Auto Focus) algorithm is used to focus automatically.
Tele/Wide
Focus
Fixed lens Vari-focal lens
Figure 2.2 Comparison of images with (a) wide (b) normal (c) tele focal length
Figure 2.3 Fixed and vari-focal lenses
Iris
(a) (b) (c)
Figure 2.4 Iris in contrast to eye pupil

Chap.2 Lens and Image Sensor Technology
9
Iris is measured in F-number, which is the ratio of the focal length to the lens diameter. Iris size is inversely
proportional to F-number. Every time the F-number increases towards a larger number, the exposure ratio will
reduce by half (Figure 2.6).
Iris includes the following types in terms of control methods:
Manual-iris
Manual-iris is adjusted with a ring on the lens. It is used when light sources are steady.
Auto-iris
Auto-iris can automatically adjust the amount of light entering with a mechanism to have a camera stay in an
optimal light level. As a result, it is mainly required for outdoor applications or the places where lights change
frequently.
There are two types of auto-iris: Video-drive iris and DC-drive iris.
• Video-drive iris: video signal is transmitted to a drive circuit in the lens and converted to currents to control the
iris motor.Becausetheampliercircuitisbuiltinthelens,aVideo-driveirislensismoreexpensive.
• DC-drive iris: the iris is controlled by DC currents. Due to the drive circuit is integrated in the camera instead of in
the lens, DC-drive iris lens features lower costs.
2.1.3 Lens Mount Types
C- and CS-mount are two major lens mount standards developed for the purpose of changing lens. The main
differencebetweenC/CS-mountlensesliesintheangefocaldistance.TheangefocaldistanceforaCS-mount
lensis12.5mmwhile17.526mmforaC-mountlens(Figure2.7).ACS-mountlenshashighercostefciencyand
smaller size because fewer glass components are used.
f/1.4 f/2 f/2.8 f/4 f/5.6 f/8
F-number
Exposure ratio
1.4
32
2
16
2.8
8
4
4
5.6
2
8
1
Figure 2.5 Relationship between F-number and aperture
Figure 2.6 F-number and corresponding exposure ratio

Chap.2 Lens and Image Sensor Technology
10
Sensor
17.526 mm
C-mount
Lens
C-mount Camera
Sensor
12.5 mm
CS-mount
Lens
CS-mount Camera
Sensor
12.5 mm
5.026 mm
Adapter Ring
CS-mount Camera
C-mount
Lens
Sensor
12.5 mm
C-mount
Lens
CS-mount Camera
IP7161
Exterior View Interior View
CS-mount C-mount
C/CS-mount
Lens
IP7161
C/CS-mount
Lens
Note that a C-mount lens can be used on a CS-mount camera by adding a 5 mm spacer (C/CS adapter ring), but a
CS-mount lens cannot.
VIVOTEK’sIP7161cantinwitheitheraCS-mountorC-mountlensbyonlyadjustinganadjustmentring(Figure
2.9). The innovative method improves lens compatibility and installation.
Figure 2.7 Comparison of focal distance for C/CS-mount lenses
Figure 2.8 CS-mount camera with C-mount lens using adapter ring
Figure 2.9 Operation of VIVOTEK IP7161’s adjustment ring

Chap.2 Lens and Image Sensor Technology
11
2.2 Image Sensor
An image sensor plays a key role in converting lights through the lens into electrical signals. Based on the
manufacturing process, there are two types of sensors: CMOS (Complementary Metal Oxide Semiconductor) and
CCD (Charge-coupled Device).
2.2.1 Sensor Types
CMOS
CMOS is a standardized and constantly developing manufacturing process used in the semiconductors industry.
EachpixelonaCMOSsensorisaccompaniedbyanamplierbasedonp-njunctionstructure.Thep-njunction
structure receives photons from the sensor and transmits them to an image signal processor.
CCD
CCD is a manufacturing process specially developed for digital imaging. A CCD is an analog shift register that
enables the transportation of analog signals (electric charges) through successive stages (capacitors), controlled
by a clock signal. The analog signals in each row of the capacitors are transmitted and converted to digital via an
analog-to-digital IC.
2.2.2 Resolutions
Resolution refers to the number of pixels in a horizontal row and vertical column of an image. For example, a
resolution of 1280x1024 means the horizontal row consists of 1280 pixels and the vertical column includes 1024
lines. The resolution of the entire image is thus around 1.3 megapixel pixels. The higher the resolution, the more
information can be rendered, and thus the better image quality.
In traditional CCTV systems, the maximum resolution is 720x480 for NTSC (National Television System
Committee) and 720x576 for PAL (Phase Alternating Line).The most commonly used resolution is 704x480
NTSC/704x576 PAL.
NTSC
Astheworld’srstcolorTVbroadcaststandard,NTSCwasdevelopedbyNationalTelevisionSystemCommittee
in 1953. With an image size of 704x480 and up to 30 frames per second, NTSC is mainly adopted in the United
States, Canada and Japan that uses 60Hz AC electricity.
NTSC signals can be displayed on a black-and-white TV because they contain luminance signals and color
information. However, it has the disadvantages of phase distortion and unstable color.
PAL
1967 saw the development of a new color encoding standard for TV broadcasting in Germany, known as PAL,
which was exclusively developed for the 50Hz AC electricity used in Europe. PAL has an image size of 704x576,
with a full frame rate of 25 per second.
Since the phase of the color information in each line is reversed, PAL reduces color distortion problems.
Features
Environment
CMOS CCD
 Smear, or blooming
 Low power consumption
 Low cost
Widely used in indoor
 High light sensitivity
 High color saturation
 Low noise in low Lux
Widely used in outdoor
Table 2.1 Comparison of features and environments for CMOS and CCD

Chap.2 Lens and Image Sensor Technology
12
D1
D1 format, also known as SMPTE 259M, is a digital image format developed by SMPTE Engineering Committee
in 1986, and is used in tape recorders. In the NTSC system, D1 has an image size of 720x480, with maximum 30
frames per second; in the PAL system, D1 image size is 720x576, with maximum 25 frames per second. D1 format
is commonly used by analog cameras.
CIF
CIF(CommonIntermediateFormat),frequentlyusedinvideoconferencing,appearedforthersttimeintheITU-T
H.261 recommendation in 1990. CIF image size is 352x288, equal to 1/4 of a PAL image. Its full frame rate is 30
frames per second, the same as NTSC.
VGA
VGA (Video Graphics Array) format was defined by IBM in 1987, with an image size of 640x480. Because a
common standard for PCs and industrial monitors, VGA has been widely used in digital image devices. IBM has
extended the VGA standard further into 1024x768 XGA (Extended Graphics Array) and 1600x1200 UGA (Ultra
Graphics Array).
QCIF
176x144
CIF
352x288
4CIF
704x576
D1
720x576
QCIF
176x120
CIF
352x240
4CIF
704x480
D1
720x480
640x480
1280x1024
1600x1200
Figure 2.10 CIF for (a) NTSC and (b) PAL
Figure 2.11 Comparison of image sizes for VGA, 1.3 MP and 2 MP
(a) (b)

Chap.2 Lens and Image Sensor Technology
13
Megapixel
A megapixel network camera features a resolution at least three times larger than that of an analog CCTV camera.
Amegapixelcameraismainlyappliedinoccasionswhenaccurateidenticationisneededsuchasvehiclelicense
plate recognition or facial recognition for it can provide images with exceptional details. Because of its high number
of pixels, a megapixel camera is also used in spacious areas such as parking lots or airports to provide images with
a wide view.
The megapixel sensor has contributed to a new breed of non-mechanical PTZ cameras, known as digital PTZ
cameras.Thecameracapturesamegapixelimageanddeliversonlyauser-denedthumbnailtothemonitorso
that users can view different images by selecting on the monitor instead of physically moving the camera.
2.2.3 Sensor Scan Modes
Image sensor scan modes include interlaced and progressive scan.
Interlaced Scan
Interlaced scan split a scene into even and odd fields that contain even and odd lines, respectively. When
renderingtheentirescene,theeveneldisdisplayedrst,followedbytheoddeld.Thetimeintervalbetweenthe
appearanceofthetwoeldswillleadtojaggededges,especiallyforamovingobject.
InterlacedscanismainlyusedinTVmonitorswithalowerrefreshrate,whichcausesthescreentoickereasily.
Interlacedscancanreduceickersbecausetheeldrefreshrateofthe interlacedscanseemstwotimesfaster
than the original frame rate.
Somemonitorssolvejaggededgesbydroppingoddeldandreplicatetheeveneldastheoddeld.However,the
vertical resolution will be cut by half.
Progressive Scan
Progressive scan renders the entire scene by displaying the even and odd lines of the frame sequentially instead of
byeld.Sincethereisnotimeintervalbetweeneachdisplay,theproblemofjaggededgeswhendisplayingmoving
objects is eliminated.
Progressive ScanInterlaced Scan
Progressive Scan
Interlaced Scan
Capture Display
Odd Field Even Field 1 Frame
1 Frame
Figure 2.12 Progressive scan eliminates jagged edge artifacts of interlaced scan

Chap.2 Lens and Image Sensor Technology
14
With the refresh rate of a LCD monitors and a LCD TV enhancing to the same level of human eyes, there is no
needtouseinterlacedscantoreducescreenickers.Progressivescanisthusreplacinginterlacedscanandwill
become the mainstream scan technology.
2.2.4 Wide Dynamic Range
Whenshootinginhighcontrast,backlight,glareandlightreectionenvironmentssuchastheentrance,ATMorthe
window side, the object will appear dark and unrecognizable. WDR (Wide Dynamic Range) technology can ensure
anidentiableimageofallobjectsundersuchconditionsbyappropriatelyexposingtheentirescene,boththe
darkest and brightest parts. VIVOTEK’s award-winning IP7142 and FD7141 support WDR, enabling the camera to
cope with challenging light conditions.
Figure 2.13 Image quality (a) without WDR and (b) with WDR
(a) (b)
2.3 Lens and Image Sensor Considerations
2.3.1 Lens Form Factors for Image Sensor
Sensorsizesarespeciedbythediagonalandmainlyinclude1/4",1/3”,and1/2".Alenscantinwithasmaller
sensor.Whenusingwithalarger-sizedsensor,forexample,a1/4”lenswitha 1/3”sensor,thesituationofdark
corners in the image will be caused.
6.4 mm
4.8 mm
1/2”
1/3”
4.8 mm
3.6 mm
1/4”
3.6 mm
2.7 mm
1/3” lens
1/3”
1/3” Sensor
1/3”
1/4” lens
1/3”
1/2” lens
1/3”
Figure 2.14 Sensor size and comparative lens size

Chap.2 Lens and Image Sensor Technology
15
2.3.2 View Angle
View angle is determined by the focal length of the lens and the sensor size. The shorter the focal length (Figure 2.15)
and the larger the sensor size (Table 2.2), the wider the view angle.
f= 8
f=4
Focal length
Horizontal view angle
Vertical view angle
Diagonal view angle
4 mm 6 mm 8 mm 12 mm
61
∘
48 ∘
73 ∘
43 ∘
33 ∘
53 ∘
33 ∘
25 ∘
41 ∘
22 ∘
17 ∘
28 ∘
Focal length
Vertical view angle
Horizontal view angle
Diagonal view angle
4 mm 6 mm 8 mm 12 mm
48∘
37∘
58∘
33∘
25∘
41∘
25∘
19∘
31∘
17∘
12∘
21∘
(a)
(b)
Figure 2.15 View angle for different focal length with same sensor size
Table 2.2 View angle for different focal length with (a) 1/4” and (b) 1/3” sensors
2.3.3 Day and Night
Infrared light has a different wavelength from visible light, leading to jagged and blurred images. The day and night
functionalitycanreducetheinuenceofinfraredlightonimagequalityandcanbeachievedbyusinganIR-cutlter
removableandIR-correctedlens.Duringthedaytimewithsufcientillumination,infraredlightisblockedtoavoid
color shift. During the night, infrared light can be utilized to enhance cameras’ night vision so as to maintain good
image quality.