IVS Motion Detection or BI?

[adventuredphoto]

What do you guys use to trigger motion for LPR cameras?

I noticed that ONVIF IVS Intrusion works good for day time detection however it's useless at night. \
At the same time the in camera motion detection is too sensitive for night time.
Better to use BI motion detection or something else?

 

[wittaj]

Most here use IVS.

Post screenshots of your field of view and camera settings.


So if you have cameras with AI and all you care about is human and vehicle detection, the AI from the cameras may be all you need.

You may find that the camera AI has got so good that doing camera AI and then BI AI is kinda overkill and adds more complexity, time delay, and potential for issues.

Whether you use the camera AI or BI motion and then send to BI AI, there are scenarios in each situation that could cause the BI AI to miss it, in particular if the camera AI was slow to react, by the time BI AI gets a snapshot, the object may be out of view. People still have plenty of BI AI that shows up as nothing detected.

Whether to use camera AI or BI AI is obviously up to you, but of course, the AI in the camera may be more than sufficient for your needs without needing BI AI. Do you need the orange box around every object? Do you want to identify animals or logos? Or is just human or vehicle sufficient.

The camera AI is useful to many people, but BI has way more motion setting granularity than the cameras, and some people need that additional detail, especially if wanting AI for more than a car or person. For folks that want AI and alerts on animals or specifically a UPS truck then they need the additional AI.

There isn't really a best practice because every field of view is different and use case and needs are different.

To many here, BI motion without AI is more than adequate for what they do.

To many here, camera AI is more than adequate for what they do.

To many here, using the BI AI adds additional functionality that the above alone can not do.

It comes down to testing with each field of view and which one gives you the most consistent results.


While some of that third party stuff is cool like tagging was it a dog or a bear, I don't need all that fancy stuff. If my camera triggers BI to tag an alert for human or vehicle and BI can accomplish what I need by way of a text or email or push or whatever, that is sufficient for my needs. I just want to be alerted if a person or vehicle is on my property and the camera AI does a fine job with that.

However, I do run BI AI on a few cameras so that it knocks out headlight shine so that the alert image includes the vehicle. The camera AI will trigger for a car, but the alert image was always just the headlights. I also run the ANPR AI module.


The true test....I have found the AI of the cameras to work even in a freakin blizzard....imagine how much a camera or BI using only motion detection would be triggering! My non-AI cams in BI were triggering all night. This picture was ran through AI (without the IVS or red lines on it) and it failed to recognize a person in the picture, but the camera AI did. This pic says it all and the video had the red box over it even in complete white out on the screen:



See this thread on how using just Dahua AI may be sufficient for your needs (and other cameras with AI would perform similar):

Who uses Dahua AI capable cameras? Reliable AI for triggering events? Pro's/con's?

 

[Arjun]

Both.

 

[Vettester]

I prefer to use just the BI option.

 

[adventuredphoto]

@wittaj Not sure how you are getting IVS to work at night. For example here it is during the day versus at night when the headlights would trigger it

 

[bigredfish]

I dont use BI I use a Dahua NVR but for me, at night I draw a small line using regular MD, IVS frequently can't see anything at 1/1000 or faster

I leave the IVS line in place but supplement it with a MD line

The downside is limited to close in bugs but I really dont see many false alerts.


Here's two examples from last night:

First one both IVS and MD pick it up (Notice both yellow and red markers)

View attachment Recording 2026-01-27 122057.mp4



On the next one IVS misses it but I got the yellow hash on the timeline from MD

View attachment Recording 2026-01-27 122229.mp4

 

[wittaj]

@wittaj Not sure how you are getting IVS to work at night. For example here it is during the day versus at night when the headlights would trigger it

OK - that is an unique field of view that is not the usual and would have been helpful in the initial post.

IVS will not work at night for LPR purposes due to the speed of the shutter that is being used and how the AI is trained.

In order for IVS to work properly, the camera needs to see the object and run it thru the algorithm. At the tight field of view and all the camera really sees is the plate and head and tail lights, it will fail to trigger because the AI was designed around being able to see the whole vehicle and not just plates.

As @bigredfish shows, for LPR, you need to use MD at night. Since the image is mainly black, it will have a lot less triggers than a bright image for MD. As he points out, you may get the occasional bug or snow flake that triggers it, but under normal conditions all I get are the plates and not anything else.

Since you are using BI, you could run this then through AI to detect if it sees a plate and then only show or alert/trigger on plates.