Zone Crossing

Neil Sidhu

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Anyone have any suggestions on how to correct a zone Crossing that are triggered with shadows? I have a line in my driveway with A>B and in the evening when some is walking on the sidewalk (which I don't want an alert for) their shadow will cross my zone lines and send me an alert. Anyway I can correct this? Also at night when a car on the street drives by, sometimes their light will cross my zone and cause an alert.
 

Vini

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You'd probably get a better response with screenshots & sensitivity settings, I suspect the answer lies within.
 

Tro

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This is something i struggled with for some time
I even created different profiles for mornings and evenings to avoid shadows from my trees - which i didn't keep (I do have a windy profile however)

you could try different angles with your zone lines/areas - but as the sun goes down - those shadows get longer...

I now simply record more and alert less - more meaningful alerts... just 2 - 3 seconds later than before...

Tro
 

IAmATeaf

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I’ve also not found a way to stop shadows or headlights from triggering. In the early days I tried all sorts of zones and crossings but gave up, now only have a single zone with movement and just fine tuned it as much as I could.

What you really need is a how fast the movement is option as a shadow being cast or headlight would be fast moving.
 

Neil Sidhu

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i have also tried the new AI tool that has been mentioned in this forum but i am getting false alerts in that as well as it analysis the entire picture when the person walking on the sidewalk sets off the trigger; it will detect that person as a human and send me the alert.. Which is not what i want. Sure it can filter out cars..

No matter how to draw these lines, that shadow will cross it!
 

Taigar

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Can you post a screenshot of someone walking with the shadow? And another one with the zones you created?
 

DsineR

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That's a tough one for zone crossing!
May be better off setting a single zone just past the sidewalk, and switching to Edge Vector. Tweak as best as possible.
Continuous recording for final option.
 

TheDank

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Hey Neil, I've been playing with zones lately and here's some stuff that I hope might help.

You could try zones like this and see how it works. Let B and C be your zones that detect someone coming from the street/sidewalk toward your porch. Separate them by some space, they don't actually have to be touching. Separate them by more more distance in the area of the frame that is close to the camera and they can be closer together in the area of the frame farther from the camera.

Be sure to have Zone A be the entire scene. Or some other zone, it doesn't matter which one as long as there is a zone that covers everything. I like to have Zone A cover everything and have B and C be my crossing zones.

Your rule will be "B>C" if you only want to detect objects moving toward your porch. If you want it to detect both directions, your rule can be "B-C".

You can also uncheck the "Object Travels (pixels)" checkbox, because you use the distance between the zones for that purpose. That is, an object must travel all the way from the B zone to the C zone to trigger. The cool thing about using zones for this purpose is that you can have different distances in different parts of the scene, just draw your zones so that the distance between them is appropriate for that part of the scene.

Another thing to keep in mind that actually makes things a little harder IMO, is that the zone motion detector uses the center of each object as the thing that must pass from one zone to another. It's not just that an object touches one zone and then touches another. The reason that makes it a bit more difficult is that the objects change size very quickly, especially shadows, and so the centers move around in somewhat unexpected ways.

Here's an example of B and C zones that could work (very quickly scribbled, you can make them better, like your originals). Notice they're far apart on the left part of the scene which is close to the camera and closer together on the right where the scene is farther away from the camera. HOPEfully this wouldn't trigger for people walking up and down the sidewalk, but would trigger for someone coming up to your porch or driveway. If necessary, you can move C farther away from B to prevent people's shadows from crossing over.

Oh, and another tip I mentioned in another thread is that in the zone editor when you're editing B or C it's hard to see B relative to C (or vice versa) because the one you're not currently editing is the same "dimly shaded" color as A which covers the whole scene. What I like to do before I start editing is first clear A. Then when you edit B or C you can see the other in the dimly shaded color. Then remember before saving to go back to A and click Invert to fill it all back in again. Kind of a lot of steps to go through, but you get used to it.

zones.jpg
 

Neil Sidhu

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Hey Neil, I've been playing with zones lately and here's some stuff that I hope might help.

You could try zones like this and see how it works. Let B and C be your zones that detect someone coming from the street/sidewalk toward your porch. Separate them by some space, they don't actually have to be touching. Separate them by more more distance in the area of the frame that is close to the camera and they can be closer together in the area of the frame farther from the camera.

Be sure to have Zone A be the entire scene. Or some other zone, it doesn't matter which one as long as there is a zone that covers everything. I like to have Zone A cover everything and have B and C be my crossing zones.

Your rule will be "B>C" if you only want to detect objects moving toward your porch. If you want it to detect both directions, your rule can be "B-C".

You can also uncheck the "Object Travels (pixels)" checkbox, because you use the distance between the zones for that purpose. That is, an object must travel all the way from the B zone to the C zone to trigger. The cool thing about using zones for this purpose is that you can have different distances in different parts of the scene, just draw your zones so that the distance between them is appropriate for that part of the scene.

Another thing to keep in mind that actually makes things a little harder IMO, is that the zone motion detector uses the center of each object as the thing that must pass from one zone to another. It's not just that an object touches one zone and then touches another. The reason that makes it a bit more difficult is that the objects change size very quickly, especially shadows, and so the centers move around in somewhat unexpected ways.

Here's an example of B and C zones that could work (very quickly scribbled, you can make them better, like your originals). Notice they're far apart on the left part of the scene which is close to the camera and closer together on the right where the scene is farther away from the camera. HOPEfully this wouldn't trigger for people walking up and down the sidewalk, but would trigger for someone coming up to your porch or driveway. If necessary, you can move C farther away from B to prevent people's shadows from crossing over.

Oh, and another tip I mentioned in another thread is that in the zone editor when you're editing B or C it's hard to see B relative to C (or vice versa) because the one you're not currently editing is the same "dimly shaded" color as A which covers the whole scene. What I like to do before I start editing is first clear A. Then when you edit B or C you can see the other in the dimly shaded color. Then remember before saving to go back to A and click Invert to fill it all back in again. Kind of a lot of steps to go through, but you get used to it.

View attachment 63021
Thanks very much on the write up! Question; what if someone comes up from the side on the lawn and then up to my porch. They would not start from the sidewalk up - this may get missed then.
 

TheDank

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Yah, you could curve the left side of B down a bit. If that gets too close to C, then you could curve C down also like you did in your original.

And... now that you mention it, someone walking into the scene from the left might not trigger at all, depending on where they go. If you think of a person walking, the center of the object they create will be fairly high in the scene. If they walk all the way up your porch, their center might never cross into C. That's the thing I was talking about when I said that the centers of the objects don't always go where you want them to go, and might not trigger. One of the things I did when I was trying to get a difficult set of zones to work is just watch the object rectangles in slo-mo over and over and over, it helps you get the feel for how objects behave. We tend to think about real-world patterns as opposed to how the motion-detection objects behave. This is evident in how we tend to draw our zones. E.g. I drew the B zone kind of along the sidewalk because I think, "someone will be walking down the sidewalk". But the center of the object will actually be higher in the scene. You should probably expand the B zone up higher. Even more so on the left. So it's really tricky, you have to spend a lot of time in "Test run through motion detector" mode, getting a feel for how the objects in your scene behave.

Anyways, yah... it might be back to the drawing board for this one. :-} But at least this is a good starting point. Do stick with it, there's that "Ahhhhhh" feeling when you finally get the zones to do your bidding.
 

devastator

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In the AI tool you can mask part of the image. I think this would solve your problem ...
 
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