Axis Network video Dokumentacja Strona 1

Technical guide to network video.Technologies and factors to consider for the successful deployment of IP-based security surveillance and remote monit

10 Figure 1.2a Setting up an event trigger using a network camera’s user interface. Event management functionalities can be congured using the

100> Activate output port: The output port(s) on a network camera or video encoder can be connected to external devices such as al

101Table 11.3a Example of devices that can be connected to the input port.Table 11.3b Example of devices that can be connected to the output port.De

102Video motion detectionVideo motion detection (VMD) is a common feature in video management systems. It is a way of dening activity in a scene by a

103Software programs that help simplify the management of network cameras and video encoders in an installation often provide the following functional

10411.4 Integrated systemsWhen video is integrated with other systems such as point-of-sale and building management, information from other systems c

105Figure 11.4a An example of a PoS system integrated with video surveillance. This screenshot displays the receipts together with video clips of the

106> Intelligent video can be used to detect reverse ow of people into a building due to an open or unsecured door from events such as evacuat

107Bandwidth and storage considerationsNetwork bandwidth and storage requirements are important considerations when designing a video surve

108When implementing 10 or more cameras, the network load can be estimated using a few rules of thumb:> A camera that is congured to delive

109MPEG-4 calculation: Approx. bit rate / 8(bits in a byte) x 3600s = KB per hour / 1000 = MB per hourMB per hour x hours of operation per day / 1000

11 viewing/recording station. Separate audio cables must also be used if audio is required. Net- work video products can also be placed and network

110A helpful tool in estimating requirements for bandwidth and storage is the AXIS Design Tool, which is accessible from the following web address: ww

111Figure 12.3a Network-attached storageNAS provides a single storage device that is directly attached to a LAN and oers shared storage to all clien

11212.4 Redundant storageSAN systems build redundancy into the storage device. Redundancy in a storage system allows video, or any other data, to be

11312.5 System congurationsSmall system (1 to 30 cameras)A small system usually consists of one server running a surveillance application that recor

114Figure 12.5c A large centralized system.Large distributed system (25 to +1000 cameras)When multiple sites require surveillance with centralized m

115Tools and resourcesAxis oers a variety of tools and information resources to help design IP-Surveil-lance systems. Many are accessible from the Ax

116

117Axis Communications’ AcademyNumber one in network video knowledge.Learn more about network video technologies with Axis’ training program.> Bro

118CORPORATE HEADQUARTERS,SWEDENAxis Communications ABEmdalavägen 14SE-223 69 LundTel: +46 46 272 18 00Fax: +46 46 13 61 30ARGENTINAAxis Communication

119KOREAAxis Communications KoreaCo., Ltd.Rm 407, Life Combi B/D.61-4 Yoido-dongYeongdeungpo-Ku, SeoulTel: +82 2 780 9636Fax: +82 2 6280 9636MEXICOAXI

121.3 ApplicationsNetwork video can be used in an almost unlimited number of applications; however, most of its uses fall under security surveillance

www.axis.com33334/EN/R2/0811About Axis CommunicationsAxis is an IT company oering network video solutions for professional installations. The company

13which to base their decisions. Network video can also be used for remote learning; for example, for students who are unable to attend lectures in pe

141.3.8 Banking and nanceNetwork video is used in security applications in bank branches, headquarters and ATM (automated teller machine) l

15Network cameras There is a wide range of network cameras to meet a variety of requirements. This chapter describes what a network came

16A network camera can be congured to send video over an IP network for live viewing and/or recording either continuously, at scheduled times, on an

172.2.1 Fixed network camerasA xed network camera, which may come with a xed or varifocal lens, is a camera that has a xed eld of view (normal/t

182.2.3 PTZ cameras and PTZ dome camerasA PTZ camera or a PTZ dome camera can manually or automatically pan, tilt and zoom in and out of an area or o

19> Preset positions. Many PTZ cameras and PTZ dome cameras enable a number of preset positions, normally between 20 and 100, to b

2The move to open video systems—combined with the benets of networking, digital imaging, and camera intelligence—constitutes a far more eective mean

20Mechanical PTZ network cameras Mechanical PTZ cameras are mainly used indoors and in applications where an operator is employed. The op

21digital zoom, the zoomed-in image often loses detail and sharpness. A non-mechanical PTZ camera is ideal for discreet, wall-mounted installations. P

22Near-infrared light, which spans from 700 nanometers (nm) up to about 1000 nm, is beyond what the human eye can see, but most camera sensors can det

23Day and night cameras are useful in environments that restrict the use of articial light. They include low-light video surveillance situations, cov

242.5 Guidelines for selecting a network cameraWith the variety of network cameras available, it is useful to have some guidelines when

25> Overt or covert surveillance. This will help in selecting cameras, in addition to housing and mounts, that oer a non-discreet or discreet i

26Another important consideration, outside of the network camera itself, is the selection of the network video product vendor. Since needs grow and ch

27Camera elementsThere are a number of camera elements that have an impact on image quality and eld of view and are, therefore, important to understa

28Many manufacturers specify the minimum level of illumination needed for a network camera to produce an acceptable image. While such specications ar

29The eld of view can be classied into three types: > Normal view: oering the same eld of view as the human eye.> Telephoto: a narrower e

3Table of contentsNetwork video: overview, benets and applications 71.1 Overview of a network video system 71.2 Benets 81.3 Applications 1

30> Varifocal lens: This type of lens oers a range of focal lengths, and hence, dierent elds of view. The eld of view can be manually adjus

313.2.3 Lens mount standardsWhen changing a lens, it is also important to know what type of lens mount the network camera has. There are two main sta

32Limits to the exposure time and gain can be set in some Axis cameras. The longer the exposure time, the more light an image sensor receives. Bright

333.2.6 Depth of eldA criterion that may be important to a video surveillance application is depth of eld. Depth of eld refers to the distance in

343.3 Image sensorsAs light passes through a lens, it is focused on the camera’s image sensor. An image sensor is made up of many photosites and each

35possibilities and more functions. CMOS sensors also have a faster readout (which is advanta-geous when high-resolution images are required), lower p

36However, when interlaced video is shown on progressive scan monitors such as computer monitors, which scan lines of an image consecutive

373.5 Image processingThree features that may be supported in network cameras to improve image quality are back-light compensation, exposure zones an

383.6 Installing a network cameraOnce a network camera has been purchased, the way it is installed is just as important. Below are some recommendatio

39Camera protection and housingsSurveillance cameras are often placed in environments that are very demanding. Cameras may require protectio

4Camera protection and housings 394.1 Camera enclosures in general 394.2 Transparent covering 404.3 Positioning a xed camera in a housing 404.4

404.2 Transparent coveringThe “window” or transparent covering of an enclosure is usually made of high-quality glass or durable, polycarbonate plas

414.4 Environmental protectionThe main environmental threats to a camera—particularly one that is installed outdoors—are cold, heat, water and dust.

42ing or hitting) than more discretely designed housings or casings for a xed dome or PTZ dome camera. The smooth, rounded covering of a xed dome or

434.5.3 Camera placementCamera placement is also an important factor in deterring vandalism. By placing a camera out of reach on high walls or in the

444.6.2 Wall mountsWall mounts are often used to mount cameras inside or outside a building. The housing is connected to an arm, which

45Video encodersVideo encoders, also known as video servers, enable an existing analog CCTV video surveillance system to be integrated with a

46By using video encoders, analog video cameras of all types, such as xed, indoor/outdoor, dome, pan/tilt/zoom, and specialty cameras such as highly

47> Serial port (RS-232/422/485) often used for controlling the pan/tilt/zoom functionality of an analog PTZ camera.> Input/output connecto

48 Figure 5.2a An illustration of how a small, single-channel video encoder can be positioned next to an analog camera in a camera housi

49enable analog PTZ cameras to be controlled over long distances, even through the Internet. (In an analog CCTV system, each PTZ camera would require

58.4 Audio detection alarm 668.5 Audio compression 668.5.1 Sampling frequency 678.5.2 Bit rate 678.5.3 Audio codecs 678.6 Audio and video synchr

50Adaptive interpolation oers the best image quality. The technique involves using only one of the two consecutive elds and using interpolation to c

51ResolutionsResolution in an analog or digital world is similar, but there are some important dierences in how it is dened. In

52When shown on a computer screen, digitized analog video may show interlacing eects such as tearing and shapes may be o slightly since the pixels g

536.3 Megapixel resolutionsA network camera that oers megapixel resolution uses a megapixel sensor to deliver an image that contains one million or

54Figure 6.3a Illustration of 4:3 and 16:9 aspect ratios.6.4 High-denition television (HDTV) resolutionsHDTV provides up to ve times higher resolu

55Video compressionVideo compression technologies are about reducing and removing redundant video data so that a digital video le can be ee

56A pair of algorithms that works together is called a video codec (encoder/decoder). Video codecs of dierent standards are normally not compatible w

57Figure 7.1b With dierence coding, only the rst image (I-frame) is coded in its entirety. In the two following images (P-frames), refe

58An I-frame, or intra frame, is a self-contained frame that can be independently decoded without any reference to other images. The rst image in a v

59Besides dierence coding and motion compensation, other advanced methods can be employed to further reduce data and improve video quality. H.264, fo

611.4 Integrated systems 10411.4.1 Application programming interface 10411.4.2 Point of Sale 10411.4.3 Access control 10511.4.4 Building mana

607.2.2 MPEG-4When MPEG-4 is mentioned in video surveillance applications, it is usually referring to MPEG-4 Part 2, also known as MPEG-4 Visual. Lik

617.3 Variable and constant bit rates With MPEG-4 and H.264, users can allow an encoded video stream to have a variable or a constant bit ra

62Figure 7.4a Axis’ H.264 encoder generated up to 50% fewer bits per second for a sample video sequence than an MPEG-4 encoder with motion compensati

63AudioWhile the use of audio in video surveillance systems is still not widespread, having audio can enhance a system’s ability to detect and interpr

648.2 Audio support and equipmentAudio support can be more easily implemented in a network video system than in an analog CCTV system. In an analog s

65Many Axis network video products do not come with a built-in speaker. An active speaker— a speaker with a built-in amplier—can be connected directl

668.3.2 Half duplexFigure 8.3c In half-duplex mode, audio is sent in both directions, but only one party at a time can send. This is similar to a w

678.5.1 Sampling frequencyThere are many dierent audio codecs supporting dierent sampling frequencies and levels of compression. Sampling frequen

68

69Network technologiesDierent network technologies are used to support and provide the many benets of a network video system. This chapter begins wi

7NETWORK VIDEO: OVERVIEW, BENEFITS AND APPLICATIONS - CHAPTER 1Network video: overview, benets and applications Network video, like many other kinds

70type of ber. Depending on the type of twisted pair or ber optic cables used, data rates today can range from 100 Mbit/s to 10,000 Mbit/s.Figure 9.

71categories are recommended for network video systems. Most interfaces are backwards compat-ible with 10 and 100 Mbit/s Ethernet and are commonly cal

72Switches typically indicate their performance in per port rates and in backplane or internal rates (both in bit rates and in packets per second). Th

739.1.3 Power over EthernetPower over Ethernet (PoE) provides the option of supplying devices connected to an Ethernet network with power using the s

74According to IEEE 802.3af, a PSE provides a voltage of 48 V DC with a maximum power of 15.4 W per port. Considering that power loss takes pl

75Figure 9.1d An existing system can be upgraded with PoE functionality using a midspan and splitter.The midspan, which adds power to an Ethernet cab

76another based on IP addresses. It forwards only data packages that are to be sent to another network. A router is most commonly used for connecting

77PortsA port number denes a particular service or application so that the receiving server (e.g., net-work camera) will know how to process the inco

78NAT (Network address translation)When a network device with a private IP address wants to send information via the Internet, it must do so using a r

79Port forwarding is traditionally done by rst conguring the router. Dierent routers have dierent ways of doing port forwarding and th

8Figure 1.1a A network video system comprises many dierent components, such as network cameras, video encoders and video management

809.2.1.2 IPv6 addressesAn IPv6 address is written in hexadecimal notation with colons subdividing the address into eight blocks of 16 bits each; fo

81Table 9.2a Common TCP/IP protocols and ports used for network video.ProtocolTransport protocol Port Common usage Network video usageFTP(File Transf

829.3 VLANsWhen a network video system is designed, there is often a desire to keep the network separate from other networks, both for security as we

83The term, Quality of Service, refers to a number of technologies such as Dierentiated Service Codepoint (DSCP), which can identify the type of data

849.5 Network SecurityThere are dierent levels of security when it comes to securing information being sent over IP networks. The rst is authentica

85server instructs the switch or access point to open the port to allow data from the network camera to pass through the switch and be sent over the n

86Figure 9.5b The dierence between HTTPS (SSL/TLS) and VPN is that in HTTPS only the actual data of a packet is encrypted. With VPN, the entire packe

87Wireless technologiesFor video surveillance applications, wireless technology oers a exible, cost-ecient and quick way to deploy cameras, particu

8810.1 802.11 WLAN standardsThe most common wireless standard for wireless local area networks (WLAN) is the 802.11 standard by IEEE. Wh

8910.2.1 WEP (Wired Equivalent Privacy)WEP prevents people without the correct key from accessing the network. There are, however, weaknesses in WEP.

9 location to view and manage video, and o-site video access would not be possible without such equipment as a video encoder or a network digital

90

91Video management systemsAn important aspect of a video surveillance system is managing video for live viewing, recording, playback and storage. If t

92other systems such as access control, building management, and industrial control. This allows users to manage video and other building controls thr

93systems where the number of cameras stays within the limits of an NVR’s designed capacity. An NVR is normally easier to install than a system based

94With a Windows client-based program, the video management software must rst be installed on the recording server. Then a viewing client software pr

9511.3.1 ViewingA key function of a video management system is enabling live and recorded video to be viewed in ecient and user-friendly ways.

96Figure 11.3b Multiple, individually congurable video streams enable dierent frame rate video and resolution to be sent to dierent recipients.11.

97Once the type of recording method is selected, the quality of the recordings can be determined by selecting the video format (e.g., H.264, MPEG-4, M

98network video product and agged to the management software program for further actions to be taken. This process oers a number of benets:> It

99> Video motion detection: When a camera detects certain movement in a camera’s motion detection window, an event can be triggered. For more o