Subscriber Discussion

Camera Calculator Request - Mounting Elevation / View

SA
Simon Adcock
Apr 28, 2015

Something inexperienced designers can fail to consider when placing cameras is the blind spot underneath the camera. Your tool seems clever but needs to show an elevation view, and the size of the blind spot on plan to be realy useful. This will vary with the mounting height of the camera, the lens angle used and the vertical angle of the camera.

(1)
JH
John Honovich
Apr 28, 2015
IPVM

There's value in showing elevation and it's something we plan to add in the future.

To start though, from the usage numbers we have already gotten (since we launched 1.0 last year), there are thousands who are happy using it as is.

That said, again, I do see the value in showing elevation for some users.

(1)
EO
Eric Olson
Apr 28, 2015

First off John, great tool. We spend a lot of time helping integrators and end users understand protection coverage through camera layouts. Equipping them with tools to perform this activity on their own helps us focus on solving intrusion detection problems.

Secondly, I agree with Simon. Blind zones are still a huge issue we see during the camera layout phase, especially as high resolution cameras allow detection at greater distances. That also introduces larger blind zones.

That being said, I certainly understand scope creep. So kudos on a great tool. When you get a chance to enhance, certainly take Simon's suggestion and place camera height on the top of the list.

U
Undisclosed #1
Apr 28, 2015
IPVMU Certified

Blind zones are still a huge issue we see during the camera layout phase, especially as high resolution cameras allow detection at greater distances. That also introduces larger blind zones.

Just curious, how do higher resolution cameras create larger blind zones? I understand using higher power zoom lenses create larger blind spots, but isn't the vertical AOV determined by the focal length and the sensor height, independent of resolution? Because of HD sensor cropping, maybe?

In general, I would think that higher resolution sensors would permit a shorter focal length lens to achieve similar PPF, and therefore actually reduce blind spots.

SA
Simon Adcock
Apr 28, 2015

They don't necessarily, but the they are often used to cover larger areas and this can lead to them being mounted higher up to see over obstructions. That's what can lead to larger blind spots.

EO
Eric Olson
Apr 28, 2015

Without getting into all the nitty gritty details, given a field of view, but more pixels, means you can achieve your needed pixels on target at a greater distance from the camera. If you are setting up your cameras correctly, the tilt should be now be optimized for viewing targets at that distance (and not trying to view the sky.) So as you look to detect at greater distances, you begin to tilt your camera up and potentially narrow your lens. Both of those actions, move your minimum detection distance farther from the base of the camera. Obviously, if you are only detecting out short distances this isn’t a huge impact.

(1)
U
Undisclosed #1
May 01, 2015
IPVMU Certified

Hi Eric.

My feeling would be that whether you mount the camera high or low, tilt it up or down, to get the same PPF at the same distance to subject, an SD camera will have a larger blind spot than a MP camera, no?

On the other hand, I do agree when using wide aspect ratios, we have a tendency to forget how different the hAOV and vAOV are, which can lead ones intuition astray.

IMHO, higher MP resolutions allow shorter focal lengths at the same PPF which mean larger FOVs and which therefore result in smaller blindspots.

That's just theoretically though, and I'll entertain the notion that the MP camera's greater resolution changes their ideal placement to the degree in that negates the larger vFOV, and even ends up having larger blindspots than SD cameras would have had. But it's not obvious to me.

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