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Guide to Closed Circuit TV (CCTV)

So would you like to play "Spot the CCTV Camera?". Eagle eyed visitors may recognise the profusion of street furniture, surrounding a single heritage dome camera keeping watch over part  of Londons' prestigious Oxford Street shopping area.

CCTV cameras on the move


SPECIALIST PAN & TILT (PT) HEADS

There are actually quite a number of very specialised, and some might say, rather rare P/T heads which can be applied to a whole range of unusual applications. Apart from the obvious marine applications where deep sea underwater heads need to be measured in (sea) horse power, or ship based units which are manufactured from the highest quality stainless steel, there are also special considerations for coastal based locations.

With a conventional aluminium casing, the sea spray can eat them up for breakfast and then spit the bits out, in time for tea!! As well as marine use, some P/T heads used in arctic conditions need to be thermostatically heated, and manufactured with special low temperature lubricants to stop the gear boxes grinding to a halt.

Likewise, under very high temperature conditions, specialist electrical components and lubricants can be used, along with alternative colour finishes to help reflect and minimise the effects of solar radiation.

In the nuclear industry, additional precautions have to be taken in the type of materials / electronics used in the manufacturing process.

One of the more unusual P/T head designs used by Doktor Jon many years ago, was a specially engineered sealed unit custom built for use in a hospital operating theatre. Apart from having to be ‘wash down’ sterile cleaned daily, the speed of movement had to be carefully calculated and the gearboxes custom fabricated to suit the weight of the large camera / lens combination.

With a 10:1 motorised zoom lens fitted to a 3-CCD sub broadcast quality colour camera, the difficulty was trying to pan along the patient with enough control to keep all the vital bits in view, whilst the surgeons every move was relayed to a distant lecture theatre.

In fact, the eventual speed was reduced down to such a degree, that the apparent movement was barely perceptible other than on the screen image; which given the superb quality of the camera, was not something one should study too closely, particularly if taking a well earned lunch break at the time!!

Speed control is also a particular problem for very high magnification camera systems, frequently used for ‘border patrol’ and coastal 'sea lane' monitoring.

How to Select a Pan and Tilt Head>

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