IVS Intrusion area inconsistent

nelsonr

n3wb
Joined
Sep 1, 2019
Messages
6
Reaction score
3
Location
Maryland
I have a Dahua IPC-HDW2231R-ZS camera (2mp starlight varifocal). In setting up IVS intrusion I am able to set the minimum size of the object. I selected "Min Size" and "Draw Target", which resulted in the blue-ish box you see near the middle. It looks fairly square, but below it resulted in a rectangle of 236x419:

1579891135397.png

If I go to the pixel counter and enter the same size it shows up much bigger:

1579891154555.png

The pixel counter makes more sense since it's a 1080p camera (1080 pixels vertically, versus the 419 shown). I also can't enter the size values manually, which is annoying. Is there a fix for this or do I need to do trial and error until I get the pixel (but not visual) size I want? Thanks!
 

105437

BIT Beta Team
Joined
Jun 8, 2015
Messages
784
Reaction score
135
I've noticed this as well and haven't found a fix. Pretty frustrating.
 

SkyLake

Pulling my weight
Joined
Jul 30, 2016
Messages
329
Reaction score
228
I think it's because of the varifocal lens. Someone with a true fixed lens camera should test it.
 

nelsonr

n3wb
Joined
Sep 1, 2019
Messages
6
Reaction score
3
Location
Maryland
Calibrate the camera. See this post.
That's interesting, but I don't have the "Global Setup" tab with the calibration options and I don't see it mentioned in this model's manual:

1579973401267.png

Either way, if we were talking about object size in inches/feet/meters/whatever, calibration makes sense. The UI appears to only be talking about pixels, though that also seems to be the case for the post you linked to.
 

nelsonr

n3wb
Joined
Sep 1, 2019
Messages
6
Reaction score
3
Location
Maryland
I think it's because of the varifocal lens. Someone with a true fixed lens camera should test it.
You might be right, especially based on the calibration talk, though that would only make sense if the numbers in min/max size meant something other than pixels. Though come to think of it, the max size is a square 8191 "units" which if you convert proportionally to the pixels somewhat makes sense. But then in that case the pixel counter is almost meaningless if it's using some other units. Definitely confusing, though I think I'm trusting the min/max size a bit more now that I think they're not pixels.
 

nelsonr

n3wb
Joined
Sep 1, 2019
Messages
6
Reaction score
3
Location
Maryland
Here are comparisons from a fixed lens HFW4231E-SE
Thanks for checking. I really don't think there is a "fix" here like I originally thought; min/max is probably just another unit. If you can calibrate the camera then it becomes more accurate with varying distance, otherwise it's probably the same throughout the whole frame.
 

usaf_pride

Pulling my weight
Joined
Mar 10, 2017
Messages
260
Reaction score
154
@nelsonr, I just checked my 2231 and it doesn't have the calibration either (nor do my 5231's). Must be only available on newer cameras. as @tigerwillow1 shows, I'm sure this is the issue.
 

tigerwillow1

Known around here
Joined
Jul 18, 2016
Messages
1,135
Reaction score
666
Until some better theory comes along I believe that the calibration is relevant only for the new human and/or vehicle detection features. Too bad questions like this can't be resolved by reading the manual.
 

105437

BIT Beta Team
Joined
Jun 8, 2015
Messages
784
Reaction score
135
Until some better theory comes along I believe that the calibration is relevant only for the new human and/or vehicle detection features. Too bad questions like this can't be resolved by reading the manual.
I agree, drawing the max/min is really just guesswork.
 
Top