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Comments on Development & Trends of High Speed Dome Cameras
Jul 25,2012   
Referring to high speed dome, there are many misunderstandings among most people who simply think “high speed” as the key figure for evaluating high speed dome. However in fact, high speed dome camera often tracks objects with “low speed”, for low speed helping manager capturing any motion details. As the important concerns to value performance of high speed dome, “quick locking target” and “stable slow” requires strict quality for inner circuit & algorithm. It is gratifying that “high speed” and “low speed” have been beginning to deeply develop based on driver & microprocessor tech achievement.
With uprising of market demand,high speed dome has been showing multiple developments and application, especially the digitalization, intelligent and web tech development fast promotes new functions of high speed dome spring up like mushrooms.
IP High speed dome Camera

IP high speed dome camera is the important subdivision from IP camera and the well combination between traditional analog high speed dome and web skill. Adding video & audio module and networking module can easily form a basic IP camera system through which audio-visual & control data can be transmitted.
IP high speed dome meets a main developing difficulty: how to smoothly transmit data in finite bandwidth resource? H 264 standard has become as a mainstream, which supports high quality transmission with good compression. In equal picture quality condition, H 264 is 1.5 times than MPEG-4 in data compression ratio.
Besides, dual-stream appearance overcomes bottleneck of net transmission and decoding resources. For adopting two encoding formats, dual stream requires more with hardware (chip, etc) & software system. Dual stream includes two solutions: first, adopting higher GHz chip to encode and compress with reduced cost, usually up to 500M at least; second, adopting two chips, each one affords on one stream, which is up to better stability. Traditional dual stream means that one high rate is for local storing (e.g. D1 encoding) and the other low rate is for network transmission (e.g. CIF encoding), moreover managing local & remote transmission. At present, the expanded application with dual stream realizes that encoding can adopt any stream rather than defined ones. It makes real-time selecting & encoding data stream, which not only realizes dual stream transmission & storing but also realizes real-time compression & coexistence in any data stream. Dual stream skill makes it true to separate encode & storing. According to network bandwidth, dual stream selects variable data stream amount, realizing local high definition storage and low data stream transmission. With the restraint of bandwidth and the demand of market, dual stream skill will keep existence and improving.
Night vision high speed dome

Evening crime great increasing promotes development of night vision high speed dome which consists of infrared skill and high speed dome. Infrared skill supports night vision dome greatly. Generally speaking, there are two ways to realize infrared effect: the positive and the negative. The positive IR means that IR illuminator sends out light to object, receives and images IR light ray coming back from sensed objects; the negative means that dome does not send out IR light but receives IR wave and images “hot picture” which is caused by IR radiation of object.
The positive IR night vision high speed dome, consisting of IR LED and high speed dome, overcomes the disadvantages of IR lamp not rotating and of common high speed domes fail to send out IR wave, even such dome faces difficulty in development 
·                           Picture quality: night vision picture appears flashlight effect, i.e. center bright but around dark, and there are vast beam and halo that will disturb picture.
·                           Effective distance of IR beam: due to scattering beam, object can only be seen within certain distance.
·                           IR LED lifespan
·                           Energy-saving & cooling: due to heavy consumption and high heat from IR LED, a bit fault may trouble whole system
·                           Positive IR “reflection limit”: nothing but within effective distance and without light sucking substance, object will send back IR light, thus monitoring is disturbed by “reflection limit”
In light of the above disadvantages, negative IR, not positive IR, has been accepted by high speed domes. It overcomes the positive IR shortcomings that negative IR skill integrates with high speed dome so as to 0Lux monitoring.
Picture quality: IR light detects all-direction arrays energy and converts them into electrical signal, creates heat pictures on screen with showing temperature.
Detecting distance: max.distance is up to 2km(effective rate of IR illuminator is only 25%).
Energy-saving & cooling: IR imager on high speed dome consumes only less than 2w (IR illuminator consumes 30w/100m or even much bigger consumption); besides IR imager circuits with non-uniform compensation need not thermoelectricity cooler
Lux sensing: beyond “reflection limit”, the reason lies in that all above -273 substances will radiate IR ray.
Poor condition monitoring: wavelength 8-14 micrometer IR ray can penetrate fog, haze and vague air, smoke, snow, etc, so as to realize normal monitoring in poor environment.
It can found that negative IR overcomes all disadvantages of positive IR, however, there have no perfect thing, i.e. the integration of negative IR and high speed dome still faces restraint. As IR wave lies in spectrum section of wavelength 0.78~1000 micrometers, 2.0~1000 micrometers being called thermal IR ray, in order to suit material’s penetration ability, we can only adopt some infrared stuff (e.g. single crystal germanium) dome shell rather than the Polycarbonate stuff. More than this, germanium-made IR material is expensive than what is made by silicon, but which has less penetrating ability than germanium. All the relevant factors limit the improvement of outdoor high speed dome.
Intelligent tracking, motion analyzing

It is always seen an important mark for high speed dome intellectualization to automatically track and alarm relying on motion analyzing, which is the combination of high sped dome and video processing skill (algorithm). Early auto tracking & motion analyzing is based on PC to read and process video data. But with DSP processing tech developing, there already have some dome manufacturers plant related module into inner high speed dome.
Wireless transmission

High speed dome integrating with wireless skill can be applied for emergency command in sudden incidents. Sudden incidents can not be foreseen in some areas such as ice-disaster in Southern China, earthquake in Sichuan province and some happened in particular work spots: Coal Mountain, offshore operation, scenic spots, etc. Once happens the above situations, the spots monitoring devices do not work well or even have no at all. At such time, it is emergently necessary to set up commanding platform and wireless high speed dome is created under such backgrounds.
Others

The mentioned high speed domes during digitalization, intellectualization and webifying integrates with other elements and into “multi-element” developed high speed dome, playing important role in subdivisions market. More than this, high speed dome itself also strengthens day by day, which is meeting market demands with oriented on privacy mask and concealing (miniaturization). The year 2008 Beijing Olympics Game calls for “Green Olympics, High-tech Olympics, and People’s Olympics” which concept can also be used to predict high speed dome tendency. It is undoubted chance and challenge for global CCTV market that “Green---more energy-saving, High-tech----more intelligent skills, Humanistic---much closer to customer or market demanding”. Facing severe development, we still stick to the Olympic-like slogan: “faster---more speed up, higher----more reliable, stronger---more functional”
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