Subscriber Discussion

Per Design Tool, 3 Cameras Would Be Enough To Cover The Entire Hallway, But Something Feels Wrong

DM
David Matyas
Feb 25, 2015

According to IP video design tool, I should be able to get great view over the lenght of a 250ft hallway (besides one sorta blind spot by one camera), using only 3 cameras. However, something feels wrong to me.

I have attached a screenshot of layout as well as the camera settings.

Thank you

Layout

specs

JH
John Honovich
Feb 25, 2015
IPVM

Look at it one camera at a time. If you have a 3MP camera, 1/3" imager and 8mm focal length, that's ~33° AoV. At 85 feet, you get 40ppf, like so:

This is 4:3 but rotating it 90° still gives the same ppf at the same distance but just with less dead spot close to the camera.

So 85 x 3 = 255 feet.

Yes, on a pure PPF basis, if you are going for 40ppf, that will do it.

DM
David Matyas
Feb 26, 2015

I guess the numbers are correct. Im surprised but cant argue with the numbers

You mentioned on a pure PPF basis it would be good. What else should I take into consideration?

If the camera is mounted on a 8ft ceiling, how big of a blind spot would you say there was? The software claims about 9 feet.

Thank you

JH
John Honovich
Feb 26, 2015
IPVM

The narrower the angle, the more likely the image does not look good, because of lensing imperfections, etc. Also, 40ppf may not look 'good' to some. It does not to me, but that's personal preference.

I am not sure about the blindspot length, but using a corridor orientation that sounds about right.

UI
Undisclosed Integrator #1
Feb 26, 2015

The main purpose here is just to monitor the hallway and see who goes into which room. So I guess it would be good enough.

Besides adding additional cameras, is there any way of addressing your concerns?

Thank you

JH
John Honovich
Feb 26, 2015
IPVM

Yes, I think it should be good enough.

U
Undisclosed #2
Feb 26, 2015
IPVMU Certified

Is there any way to estimate what the depth of focus would be on something focussed 85' out? As you have mentioned before you can't count on the nearest shots being in focus when your tele'd significantly beyond that.

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