TVL vs. LOR

[billm 0]

I'm in the process of designing a CCTV system for my home; not sure yet if I will use a PC or standalone DVR. If PC, its either going to be the Geovision or I-View board.

 

In the meantime I'm testing cameras for the best possible picture. Can someone explain the difference between TVL and LOR. If a camara says its 570 TVL does it also mean its 570 LOR, I'm beginning to think not.

 

Thnaks

Bill

[bryan1656 0]

TVL and LOR, along with other abbreviations, all usually refer to Horizontal Lines of Resolution when refering to camera resolution/output.

 

The NTSC (color) standard for composite video is 525 horizontal lines, however, not all of these are actually viewable. Some are used for other information. IIRC, the actual *viewable* lines number around 420?? Someone correct me if I am wrong, here.

 

At any rate, the higher the horizontal resolution of a camera, the better. You may not end up with that many lines being viewable or recordable, but it gives you more to work with on the "front end".

 

Then there is the whole issue of whether or not the camera actually produces the number of lines in their spec sheet. Just because the CCD or CMOS chip is capable of that resolution, doen't mean that that is neccessarily what is coming out of the BNC in the back of the camera.

 

Hope this helps!

[kaysadeya 0]

Welcome Bill.

 

I'm still learning here, but one important point is that the "best picture" is not strictly a function of camera resolution. Lighting, lenses, camera quality, and camera settings also play a big role. Your best bet is to use the members of this forum as a sound board before investing in any camera.

 

I'm also in the process of installing a CCTV installation for my home. I spent a great deal of time researching the PC-based vs. dedicated DVR question. After a lot of research, I settled on a dedicated Kodicom DVR. You can read the other threads, but the bottom line is that my existing PC wasn't "powerful" enough to host a GeoVision card. There are also some "hidden" costs for a PC-based system, such the need for a separate card for realtime monitoring.

[Cooperman 0]

originally posted by bryan1656:-

Then there is the whole issue of whether or not the camera actually produces the number of lines in their spec sheet. Just because the CCD or CMOS chip is capable of that resolution, doen't mean that that is neccessarily what is coming out of the BNC in the back of the camera.

 

originally posted by kaysadeya:-

.... but one important point is that the "best picture" is not strictly a function of camera resolution. Lighting, lenses, camera quality, and camera settings also play a big role.

 

Ain't that the truth guys

 

Just to clarify a couple of points though. The NTSC colour system (525 lines), PAL & SECAM (625 lines), refers to the number of horizontal lines stacked one above the other, that make up the picture.

 

The horizontal resolution (H.R.) of a camera refers to (if you like) the number of points that can be resolved along a line ( a bit simplistic but I'm sure you get the drift).

 

With this in mind, the higher the horizontal resolution of the camera imager and its associated circuitry, the sharper the image will appear (if correctly set up, focussed, exposed etc. etc.).

 

Whilst CCTV cameras generally limit at or around 600 lines H.R., broadcast cameras actually go way beyond this, so although they still use the 525 or 625 line scanning systems, the horizontal resolution may be 700+ lines.

 

An example high end industrial / broadcast camera is on the following link:-

http://www.ikegami.com/br/products/sdtv/sdtv_camera_frame3.html

 

Now what could we do with a 750 line resolution colour camera?

[qman 0]

Well, when it comes to the DVR card, I cannot stress this enought. More and more people have problems with GEO cards, expecially since geo is going AGAIN to change their boards. Why going thru the trouble, which is why I only sell I-view boards now, and got rid of GEOCRAP.

 

Do a search around the forum, and see how many geo problems and how bad the lack of support on part of GEOVISION is.

 

I-View, on the other hand, I'm not going to sit here and make a sales pitch, just go also around the board, and see what members that had bought it have to say about it.

[rory 0]

 

Now what could we do with a 750 line resolution colour camera?

 

First we need a DVR that will record at that quality

i guess a simple capture board will do then write your own software...lots of hard disk drives also...?

 

how bout the 3CCD chip cams, like medical - engineering cams...Mega pixels..

[Thomas 0]

Eh, drive space is getting cheaper. Perhaps one day we'll drop the idea of compression all together. Work some magic by recording the F-stop, T factor, what the lens is set to with the data, maybe work some CSI type of magic.

[billm 0]

This board is great, ask a question and get a whole lot of good information.

 

Herminshs now has me leaning towards an I-View rather than Geo and Kaysadeya has me liking the Kodicom even more. Guess I have a whole lot of reasearch ahead of me.

 

Also, partially what got me into this was that I'm involved with upgrading my office space with a new CCTV system. I have 9 cameras now with a multiplexer and time lapse recorder, I find it useless.

 

I'll post the proposed design tomorrow in the design section and see if any one has any comments... better choice of equip, etc.

 

Thanks again everyone.