Network Camera

Network camera profile

Network camera is a kind of combining traditional camera and network technology produces a new generation of video camera, it can turn images through the network to the earth at the other end, and distal visitors, no need for any professional software, as long as the standard Internet browser (such as "Microsoft IE or Netscape) can monitor the images. Network camera embedded chip, using a built-in camera embedded real-time operating system. Video signal transmitted from digital by compressed effectively chip compression, through the network bus teleport to Web server. Internet users can use directly browsers on Web server on camera image, subscribers can also control the camera lens action or to yuntai system configuration operation.

The application of network cameras

Besides providing high-speed broadband network information network access to the outside also can replace bronze axles cable image transmission lines will monitor real-time image into broadband information network application scope, this makes the information network instead of traditional closed-circuit television become inevitable. Based on PC multimedia monitor system function stronger, but mainly small range monitoring. When transmitting distance or need on the Internet, based on PC multimedia monitor stability is not good enough, power consumption, high need someone to the openness of substation, software is bad. These problems based on the network and the network video monitor embedded technology provides the stage.

Network cameras will converted image based on TCP/IP network standard packets, which makes the pictures taken by camera RJ - 45 Ethernet interface or WIFI WLAN wireless interface transmitted directly to the Internet, through the network can distal monitor screen.

Network camera adopted the most advanced camera technology and network technology, has the formidable function. The built-in system software can achieve genuine plug-and-play, users waived the complicated network configurations. The built-in high-capacity memory storage alarm triggers the image before, The built-in I/O port and communications mouth facilitate expansion external peripheral equipment such as entrance guard system, infrared sensors, all-round haeundae, etc. Provide package (SDK) facilitate the user to fast development and application software.

Network camera are widely used in education, business, medical, utility and so on various aspects fields

Network camera composition principle

Network camera generally by lens, image sensor, voice sensor, A/D converter, images, sounds, controller network server and external alarm, control interface components.

1, the lens

As the network camera lens front parts, have fixed aperture, automatic aperture, automatic zoom, automatic variable times, and the simulation of camera species such as the same.

2, the image sensor, voice sensor

Image sensor have CMOS and CCD two patterns. Both complementary metal oxide semiconductor CMOS, CMOS basically is to use and silicon germanium these two elements made by the semiconductor CMOS negatively charged and the positively charged transistors to achieve the basic functionality. These two complementary effect produced by the current can be processing chip records and interpret images. For the main CMOS CCD advantage is very province electricity. Unlike by diodes composition of CCD and CMOS circuit almost no static electricity consumption. This makes the consistence of ordinary CCD CMOS only 1/3 of CMOS important question is, in dealing with the rapidly changing images, because the current transform too frequent and overheating. Dark current suppression is good, not a problem, if inhibition of bad very easy to appear speckles.

CCD image sensor consists in a two-dimensional monocrystalline substrate arranged photoelectric diodes and transmission circuit constitutes. Photoelectric diode light into electrical charge, then after conversion circuit transmission and output.

Usually, transmit excellent image quality equipment are adopted the CCD image sensor, and pay attention to power consumption and cost of product chooses CMOS image sensors. But new technologies are overcome each device body inherent weaknesses, simultaneously retainde the suitable for specific purposes of certain features. This part of the same and the simulation of the camera. Voice sensors pick up sound device, or is called a microphone, and traditional microphone principle as well.

3, A/D converter

A/D converter is the function of the image and sound etc analog signal converted into digital signals.

Based on the image sensor module CMOS mode have direct digital signal output interface, without A/D converter, But based on CCD model of image sensor module if have direct digital output interface, also need not A/D converter, but because this module mainly for the model design, only analog camera output port, so need to conduct A/D conversion.

4, image, sound encoder

The A/D conversion of images, sounds, digital signal, according to certain format or standard code compression. Coding compression aims to easy to realize sound/visual signals and digital multimedia signal, Facilitate the computer system, network, as well as the world wide web not distortion to transfer the signal. At present, the image coding compression technology has two kinds: one kind is hardware encoding compression coding, forthcoming compression algorithm in curing chip, Another kind is based on DSP software code compression, namely the software running on DSP on image coding compression. Similarly, voice compression can also adopts hardware encoding compression and software compression, its coding standards have MP3 format etc.

5, controller

A controller is network camera heart, it is shouldering the management and control of network cameras work. If is hardware compression coding, controller is an independent components, If is the software code compression, controller is running coding compression software DSP, namely, both as one.

6, network servers

The web server provides network camera network function, it adopted your RTP/RTCP, UDP, HTTP, TCP/IP and other related network protocol that allows users from their own PC using standard browser according to network camera IP address to network camera network cameras

A visit to watch a real-time image, and control the camera lenses and yuntai.

7 and external alarm, control interface

Network camera for engineering application provides practical external interface, such as control of 485 interface, used in yuntai warning signal input and output of I/O port. Such as infrared sensor is found to have goals to appear, hair alarm signal network camera, network cameras adjusted automatically lens direction and real-time video, On the other hand, when network cameras to detect a moving target appeared, can also go to outside the alarm-immediately.

The basic principle of network camera is: image signal after lens input and sound signal after the microphone, the image sensor input of electrical signal is transformed voice sensor, A/D converter analog signals into digital signals, repass encoder according to certain coding standard code compression, again controller under the control of by the network server according to certain network protocol on LAN or INTERNET, controller can also receive alarming signals and sent out alarming signals, and required A controlled signal.

8, image coding standard

At present, the network camera image compression coding standard basically has MPEG4, h. 263, h.264, M - JPEG, etc.

MPEG4

So-called MPEG refers to the moving pictures expert group by ISO formulated series on the audio and video signal and multimedia signal compression and uncompress technology standards. So far, has formulated a complete and approval of execution are: 1991 approved MPEG1, MP3, In 1994 approved MPEG2, 1999 approved MPEG4 and MP4. In formulating standard has: MPEG7 and MEPG21.

H. 263

H. 263 itu-t is proposed as h. T 324 terminal use video decoding Suggestions, h. 263 after continuously improve and the many upgrade has mature gradually, now most instead of h. h. 263 261, and because of the low bandwidth can in the transmission of high quality video and growing popularity.

H. 263 is based on motion compensation DPCM hybrid coding, in motion compensation DPCM mixed encoding, in the sports search is conducted on the basis of motion compensation, and then use DCT transform and zigzag pattern scanning coding, thus obtains the output streaming. H. 263 in h. 261 Suggestions based on the motion vector, will increase to half a pixel search search, Increased again at the same time unlimited motion vector, based on the syntax of the arithmetic coding, senior prediction technology and PB frame coding and so on four advanced options, Thus up to further reduce the code rate and improve the quality of coding purpose.

h.264

H.264 is itu-t T VCEG and ISO/IEC MPEG video group of the joint development of a new digital video coding standard, it is both itu-t T h.264, and ISO/IEC MPEG4 tenth part.

In the same reconstructed quality, h.264 than h. 263 can save about 50% of bitrate, than current video format according to the realization of MPEG4 in performance is increased by 33% to the left.

M - JPEG

M - JPEG technology is a sport static image compression techniques, it brings the movement of the video sequence as continuous still images to handle, the compression technology way alone fully compressed each frame, the editorial process can be random storage each frame, can be precisely to frame editor. But M - only to frame the mainland JPEG compress space redundancy, right frame between the temporal redundancies compression, so the compression efficiency is not high.

Editor this segment network camera features advantages

Application advantages

Network cameras can not only be used for computer LAN based on regional monitoring, such as residential surveillance, office buildings, Banks, traditional monitoring; stores, etc. Through the INTERNET can also be used in new type to cross regional remote monitoring and online display, remote children and elderly care, unattended communication computerrooms monitoring, tourist attractions online broadcasting, product online exhibitions, etc. Still have a bit is now 3G network of ascension that allows network camera for a brighter.

Features:

The images were M - JPEG/h.264 compression coding, through network using TCP/IP protocol for transmission, Through the network cameras or lens, yuntai and other external equipment operation control, A built-in 10M / 100M Ethernet RJ45 interface, which can be realized by web remote interface; A parallel I/O mouth, can connect to the external sensor for automatic alarm, also can control or external equipment for linkage alarm functions, A RS45 serial port, can to lens, yuntai control, or link other external equipment, Embedded WEB SERVER, internal network camera provides a WEB SERVER, allowing users to use standard land from PC browsers to various interfaces, operating; With separate security mechanism and to operate this camera can land grading other users access validation, Have the centralized management and control center of monitoring network and centerless distributed monitoring network, Built-in real-time operating system, support the software to download and configuration Settings, convenient upgrades and operation management.

Choose network camera erroneous zone

Network camera (network video server, video server, network video converter, etc.) are entering in practical engineering.

Eliminate misunderstanding in understanding, recognized the characteristics of network cameras can speed up the popularization of practical application.

Question:

In selecting the simultaneous digitalization multimedia monitor product, because the subjective and objective factors produced a variety of doubts, before a few years hard to widely popularized and applied. Stepping into the 21st century, with the development of information revolution, as broadband and promote the popularization of the Internet, the consciousness of people has a corresponding change, but there are still many understanding of the error, hindered monitoring digitalized and networking development just.

1, network camera too "expensive"

In the choice to monitor products, mention network cameras, people will think network cameras to 9 million yuan one, with the flower thousand pair of dollar buys common video camera compared too expensive.

A W74GM network camera video capture card is equal to the computer + + CCD common video camera + nic + OS + software, namely in monitoring terminal, only need a network cameras can send network video. So take common video camera and network camera than price is not appropriate.

2, network cameras "technology is too demanding"

In the choice to monitor products at the same time, a mention network cameras, people will think network too complex, technical requirement is too high. Actually, this is a kind of fear of psychological counted in, the Internet is to take a family, a few children aged WanDeZhuan the network, the network of engineering contractor and users is nearly transparent, or need hardly tube he.

At present, the network basically based on TCP/IP. Although the network itself agreement, network equipment (including network cameras) itself, but due to the complex technology unification of network protocol, each of the manufacturer of the product are done just know that turns on/off the phone, protection/removal and other basic operation is ok, all other to network products to complete, true automatic fool type operation, don't need intervention too much.

3, network cameras "image quality is poor"

Based on network, network video camera simulation based on local images, video monitoring system by using optical fiber cable (few), although all is the monitoring, this is two completely different system structure.

As network camera's manufacturer, we emphasize network camera isn't everything, because the network itself is not everything. In the transmission distance not too far, decentralizing little remote transmission, again have no need of circumstances, we still recommend user using simulated image monitoring system.