How to test a camera's true Resolution

[kandcorp 0]

How would one test a camera's lines of resolution. What kind of equipment is needed and who has has experience in this field.

 

The reason I am asking this is because I have recently found out of a company who has been selling a camera for years stating it is 480 TV Lines of resolution. To my surprise I have found out the camera is actually a 420 TVL. Also, they lied about the image sensor too. Stating Super Sony HAD when in fact it was only a regular Sony, but thats another thread.

[rory 0]

a good eye

 

actually, i'll wait to hear on that also. As for Sony Super HAD its not much different than Sony normal .. so harder to tell, if they claimed Sony Exview then you would know the difference easily, there are ways to check that.

 

I got a bullet from Provideo that claimed Exview, and used to be Exview, but I got a bunch of them that were not, even still said it on the box. Even the ones I got claimed Day Night when clearly Exview Color is not Day Night, though it does switch to a monochrome mode these days, it still stays the same lux and res, and IR cut filter stays on. Anyway, even their tech told me they are not exview anymore, just Super Had which is not low lux like Exview, so I stopped buying Provideo from there on.

[kandcorp 0]

Yea thats another thing....see it all the time.

 

Everyone is claiming TRUE day/night cameras but there not.

[Thomas 0]

To test a cameras resolution (and remember I'm doing this from memory so my numbers may be a little off) you need a testing chart, tripod, and fixed focus lens as well as a monitor (can't do this on a DVR). Aim camera at the line test. Move camera till testing chart fills the screen. Look at the lines and see where they blur together. That is your resolution. AGC should be off. Use a good lens (10 to 13 mm I think).

[kandcorp 0]

I would be interested in a LINK if anyone has one on an exact method of testing.

 

Hey Tom, Do you guys eat DELL boxes for lunch

[rory 0]

dont know, ill do a search if someone doesnt come up with anything, but this is a good link for general CCTV tools:

http://www.ltctrainingcntr.com/11_Tools_Page.htm

[Thomas 0]

I can do you one better then a link.

 

http://www.amazon.com/exec/obidos/tg/detail/-/0750678003/qid=1130884284/sr=8-1/ref=pd_bbs_1/002-7213212-4186467?v=glance&s=books&n=507846

 

The previous verison had a testing chart on the back and the instructions.

[rory 0]

These books are good, dont know if they have testing charts or not, I never read the whole thing much ..

 

http://www.ltctrainingcntr.com/02_Installation_Field.htm

 

http://www.ltctrainingcntr.com/02_Manuals_HomePg.htm

[SeanMort 0]

For a test chart got to http://www.cctv-focus.com/

 

I don't think the new LTC books have a chart in them but the training material is excellent. Thomas is right about the method, but for it to be "true" it has to be measured at the centre of the monitor CRT as the monitor also has a resolution factor that fades on the peripherary of the tube. We used to get super resolution (around 700TVL) with the old tube cams but the CCD's seem to be catching up !!

Interesting enough, a couple of years ago the British Home Office's Police Scientific Development Branch researched and developed a performance test target called Rotakin for CCTV systems. One of the important things that came out of their research is that there is a factor called "static resolution" and "spatial resolution" (the resolution of a moving target). The target rotates at 25RPM and is calibrated with B&W bars and the like. The target is intended to allow installers to set up cameras for optimal use viewing moving objects. You had to invariably use the shutter settings with varying results (how many people really use this feature ??). It was just so expensive that it ended up being used by manufacturers, trainers and those with a few $$. I now have one gathering dust in my store (any offers ?).