Guest Suzanne Posted February 16, 2005 Posted February 16, 2005 HI Question on CCTV resolution. I have a monitor with 800*600 resolution which I want to split into four pictures does anyone know whether it will be possible to distinguish clearly the outline of a person on one of these images? Also I was wondering what the effect of cold would be on the clarity of the picture? I have heard that cold slows down the picture refresh. Thanks Suzanne
Brian c Posted February 16, 2005 Posted February 16, 2005 Suzanne, a lot depends on the euipment being used to record and split the cameras. In my opinion, the higher the resolution of the screen, equals a better quality of image. I do know that LCD and Plasma monitor screens are nowhere near as good quality as standard high res cctv monitors. Wether you will get a clear outline of a person, again depends on your dvr or multiplexer. The image file size and resolution of your dvr/multiplexer recordings and your camera's resolution, will determine the maximum resolution that can be displayed on a capable monitor. Cold affecting refresh rate. I've never heard of that before and again that would be down to the dvr/multiplexer as well as the monitor. I would've thought however, that refresh rates would be controlled by a processor chip and that extreme cold could cause problems. Although a constant cooling should improve it. If you don't know......ask.
Guest Suzanne Posted February 16, 2005 Posted February 16, 2005 Thanks Brian I guess I have a few more items to consider Suzanne
Brian c Posted February 16, 2005 Posted February 16, 2005 No problem. Check back later. I'm sure others will have more to add. If you don't know......ask.
Rich Posted February 16, 2005 Posted February 16, 2005 Hi Suzanne How cold are you talking about? What type of monitor do you have, Tubed Monitors (CRT) have refresh rates but unless your using it in an extra cold controlled area I doubt you would have a problem. Also monitors generate heat so it would have to be very cold. TFT Monitors do not use refresh rate in the same way, they use pixel response times and possibly could suffer slightly more from the cold, but I wouldn't think so much as you would notice. Splitting a screen of 800 x 600 will give you 400 by 300 pixels per camera, they will generally look sharper on a CRT monitor on split screen, but as Brian says It greatly depends on the resolutions of the camera, and the resolution of the through signal of the DVR, Recorded images may be of lower resolution depending on the DVR settings. If you are using a VCR and CRT monitor you wont really have to worry as much about matching resolutions. You say you want quality on a split screen, but what really counts generally is the quality of the individual recordings of each camera. Just because you view 4 cameras at once live, doesn't have to mean you have to settle for a lower resolution images at the recording end of the system. A little more information about the environment of your system would be helpful.
Rich Posted February 16, 2005 Posted February 16, 2005 Sorry, just read your topic title. I would think that looking at cameras on an 800x 600 split screen monitor, you will notice a depreciation in picture quuality. What is it you are monitoring, Is live view more important than recorded full screen images? How much detail do you require, what lenses do you have on the cameras?
Guest Suzanne Posted February 16, 2005 Posted February 16, 2005 Richard Thank you for your reply. The live feed is the most important aspect. It is a safety system in which people are monitored on screen to check they have not wandered into an unsafe area. It is important that the operator could spot a 2 year old walking across the screen, however he/she will not need to recall features. It is possible that there would be a large number of people to be watched. At the moment I do not have information on the rest of the equipment that will make up the system as the focus has been on the monitor capabilities at this stage. Thanks Suzanne Sorry, just read your topic title.I would think that looking at cameras on an 800x 600 split screen monitor, you will notice a depreciation in picture quuality. What is it you are monitoring, Is live view more important than recorded full screen images? How much detail do you require, what lenses do you have on the cameras? 40667[/snapback]
Guest PaulR Posted February 16, 2005 Posted February 16, 2005 The more traditional Cathode Ray Tube monitor will give a better image quality, plus will tend to give you a better colour balance. You could do with a good PTZ camera (or four ) if you have a guard controlled camera, who could zoom in etc to get a clearer image.
secboy Posted February 16, 2005 Posted February 16, 2005 Hi Suzanne a little bit of info which may help you is that it is recommended that the target height when viewed on a main monitor should be no less than 10% of the height of the viewable screen any less and the target will probably be missed by any viewer and of course the larger the target the better the chance of being noticed. If you are looking to upgrade the cameras as well some of the other guys are more clued on the gear available but just to mention in laymans terms the use of external detectors triggering an external dome camera and even giving an audible warning while moving the camera to a preset position and zooming to a preset level is posible with todays technology and may be suitable if like you say they are to monitor specific hazardous areas with a low people thru rate,hope that has helped,Paul(Essex) Have reread and realise that if you have a high thru rate the detector solution may not be any good for you but at least you know its an option!!!.
Rich Posted February 16, 2005 Posted February 16, 2005 A Large Hi resolution CRT monitor would probably be most suitable, with Hi res PTZ cameras with zoom capabilities, or correctly specified fixed camera/lens combinations Who is designing your system? The monitor is the least of your worries (and probably the cheapest) if you haven't taken into account cameras and lenses etc. If you are using moving cameras with zoom lenses, and you want the best picture possible while the camera is moving then in my oppinion forget about digital monitors and stick with a CRT monitor. (Quality:Price) The ability to have a motion detection option on the quad setting off alarms and ptz preset positions sounds like it could be usefull to you also. And at least I would suggest you use this thread you have started to refer to for the rest of the system. In reality if your worried about 2 year olds being in the area you are monitoring then I am worried as to why you are asking questions openly about important aspects of your system. If the monitoring is for safety reasons then I am even more worried. You should have a professional design your system for you, either get some companies in to put together a quote and do a survey or pay for a consultant to pay you a visit. If you are wanting some sound advice to refer the quotes you do get against then the more information you supply the more help you will get. Things taken into consideration when designing a CCTV system are, What are you doing with the camera images, How much detail you need to see, The area you want to view, the light levels of the area you want to view, is it internal or external. Is the camera location viable for installation.... The list goes on.
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