Omega Owners Forum
Chat Area => General Discussion Area => Topic started by: Field Marshal Dr. Opti on 06 July 2010, 12:03:46
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Can anyone tell me why the images produced by CCTV on Crimewatch are all so piss poor?
Presumably... these CCTV systems cost mega bucks.... but the end result is usually some grainy blurred picture....that could be anything....Any ideas?
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Can't really reason why.....
I install HD CCTV at 620/550/480 TVL and pictures are excellant, even in poor light. Can only think that some of the systems are older type and grainy because they are poorly maintained.
None of the evidential systems I have installed give poor pictures unless the lenses are not cleaned or focussed on a regular maint schedule, and perhaps some of the "shop" pictures are the d.i.y systems you can buy in electrical wholesalers or B+Q??
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I think (often) the older CCTv. resolution is only 276 horiz. lines (or thereabouts)....thus, re-scaling for broadcast Tv. and latterly; HDTv. means, although to the CCTv. operator the images are perfectly usable, there`s a significant amount of 'expected' detail missing when broadcast on a domestic Tv.
It`s also more fun trying to identify which of the 'fuzzy', behooded-scallies was the perp.!....although generally the Met. go on the principle of: "The black one/s did it!" ::)
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I think (often) the older CCTv. resolution is only 276 horiz. lines (or thereabouts)....thus, re-scaling for broadcast Tv. and latterly; HDTv. means, although to the CCTv. operator the images are perfectly usable, there`s a significant amount of 'expected' detail missing when broadcast on a domestic Tv.
It`s also more fun trying to identify which of the 'fuzzy', behooded-scallies was the perp.!....although generally the Met. go on the principle of: "The black one/s did it!" ::)
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Debs................that can't be right..............you sure it wasn't the Pikeys???? LOL!
What you say is quite correct. The parameter for evidential quality CCTV requires at least 540 TVL and can be colour or B+W, but there are so many older systems out there in the field, that after rebroadcasting of the (usually) VHS image its grainy and poor. With todays DVR's, the digital image is transferred via memory stick or DVD, and is re-broadcastable in the same quality, therefore in a few years the overall quality will be acceptable to all. Most images I have to go to court now with are so good, the "scally" can't make out its not him/her, as the pictures can be "blown up" digitally to even show the zits on their faces!!
90% of convictions are on the premise of "yeah, its me, its a fair cop" because there is now little doubt. I look forward to the HD age of TV catching up with the CCTV world sometime soon.
Mike.
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My suspicion is that cameras are set up as a compromise between wide angle so that they catch as much as possible, and narrow angle, so that they get the detail.
When c/w or an analyst go through the footage, they blow up any area of interest to see if that improves the visibility/recognisability to the naked eye.
P.S. I'm not sure you can assume that they all cost mega-bucks :D
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No, some HD or Hi-Res cameras at 620 TVL only cost £120 trade!
But.......there are some cheap and nasty "CCTV" systems sold by B+Q et all costing £180 with 4 cameras and a B+W monitor that are totally RUBBISH, but that doesn't stop shops buying them to get CCTV on the cheap, and they produce crap pictures that don't rebroadcast very well.
Horses-Courses, pay peanuts, get monkey crap.