Subscriber Discussion

Looking For Information On Geovision 120-FER12203-000

UI
Undisclosed Integrator #1
Jun 13, 2016

Looking for information and quality on Geovision 12mp fisheye. Also do you know if the zoom capability is good at 200 feet?

JH
John Honovich
Jun 13, 2016
IPVM

We have not tested that Geovision fisheye.

However, at 200 feet, no 360 fisheye is going to provide much details. Its a fundamental constrain of FoV vs PPF, demonstrated here:

Notice, that at 200 feet, pixel density is a pitiful 3.2ppf.

I also included two smaller circles showing 100 and 50 feet distances, and that's not much better at a respective 6.4 and 12.8ppf.

Fisheyes are just not designed to see details at long ranges.

(1)
U
Undisclosed #2
Jun 13, 2016
IPVMU Certified

At 200ft, no 360 fisheye is going to provide much details.

If you care enough, it can apparently capture crossed insect antennae at 20ft... (When used with optional VMS magnifying glass.)

(2)
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UI
Undisclosed Integrator #3
Jun 13, 2016

While it is an impressive resolution for a panoramic camera, as others have said there is no way you will get much more than a few pixels at 200' and compression is sure to turn it into one blurry artifact. We have used the Panasonic 12MP panoramic WV-SFV481 which is very similiar in specification. While phenomenal for a panoramic camera do not expect much. If a Hikvision 6MP Panoramic provides decent enough detail at ~20' then expect this to provide the same at roughly 40'.

U
Undisclosed #2
Jun 13, 2016
IPVMU Certified

...if a Hikvision 6MP Panoramic provides decent enough detail at ~20' then expect this to provide the same at roughly 40'.

I'm not sure I can agree with that since the reason we're in this situation is because of the way things get worse quickly, in a non-linear manner.

I would agree that, all others things being equal, a 12MP camera would provide 2x the details as a 6MP camera at 20 ft.

I could be wrong on either count though, I'd have to study it more. What do you think?

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UI
Undisclosed Integrator #3
Jun 14, 2016

You are correct. There are many, many variables. For a simplistic equation to show how far off-base a 200' viewing distance is I think it illustrated the point though.

U
Undisclosed #2
Jun 14, 2016
IPVMU Certified

There are many, many variables...

Agreed.

For instance, whether the object that is 200ft away is dead center of the FOV or on the periphery is equally important.

A dead center object can easily have 2x the ppf of an equally distant outer object.

JH
John Honovich
Jun 14, 2016
IPVM

What is dead center on a 360 fisheye? An object 200' directly below the camera?

When we test panoramics, we always test on the periphery since that is the most common use case when you mount a camera facing downward / parallel to the ground and looking at a target away from the camera on the ground.

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U
Undisclosed #2
Jun 14, 2016
IPVMU Certified

What is dead center on a 360 fisheye? An object 200' directly below the camera?

Yes.

When we test panoramics, we always test on the periphery since that is the most common use case when you mount a camera facing downward / parallel to the ground and looking at a target away from the camera on the ground.

Of course. My point was that U3's double the sensor resolution at double the distance only would hold for things directly beneath the lens. The more peripheral things are, the more non-linear degradation occurs.

This happens to a slight degree in all lenses, but is extremely noticeable in fisheyes.

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