Can someone explain anti-dither and Record Delay settings?

[sumguy]

The camera is a HDW2431T-AS-S2. I have some video detection zones set up, and had recently set the detection period to all day, every day (instead of just the evening / overnight). The camera overlooks a parking lot, and it does capture when some external IR cameras turn on and off.

In the motion detection settings, I have anti-dither set to 2 (it cam be 0 to 100 seconds) and I have record delay set to 10 (it can be 10 to 300 seconds, so I have it set to the minimum).

I was snow blowing the parking lot today, and halfway through I remembered that I had set the detection to 24 hours, so I was anticipating a ton of useless in-camera recordings and emails.

Instead, it just captured me walking once along part of the scene, but none of the snow blowing. So I'm glad I didn't have a lot of useless captures and emails, but I'm pissed that I don't seem to have the detection control over this camera that I thought I did.

Last night we had "thunder snow" - about 6 lightning flashes, and each one was captured as a short video clip and I got an email (but the email did not contain the image with the actual flash). I have an older Dahua in another location and it does send 1 and sometimes several images per detection event (sends them as email - it has no internal SD card) and it always captures lightning flash images.

So in this 2431 I have "red" and "yellow" detection zones with slightly different thresholds. But like I said, it did not detect anything in the "yellow" zone where there should have been lots of motion.

I'd like to know more about anti-dither and record delay and if they played a role here.

Also - what is the "smart plan" setting? It's a light bulb icon that you seem to be able to turn on and off, but no actual settings to fiddle with. I think it was (is) on currently.

 

[wittaj]

Smart Plan is which of the AI rules do you want to use instead of motion detection - it could be people counting, IVS, heat map, etc. So you select Smart Plan and then pick the item you are interested in and set it up.

From the Dahua wiki:

Anti-dither (AKA Cool Down Time between the next event): Here you can set anti-dither time. The value ranges from 5 to 600s. The anti-dither time refers to the alarm signal lasts time. It can be seem as the alarm signal activation stays such as the buzzer, tour, PTZ activation, snapshot, channel record. The stay time here does not include the latch time. During the alarm process, the alarm signal can begin an anti-dither time if system detects the local alarm again. The screen prompt, alarm upload, email and etc will not be activated. For example, if you set the anti-dither time as 10 second, you can see the each activation may last 10s if the local alarm is activated. During the process, if system detects another local alarm signal at the fifth second, the buzzer, tour, PTZ　activation, snapshot, record channel will begin another 10s while the screen prompt, alarm upload, email will not be activated again. After 10s, if system detects another alarm signal, it can generate an alarm since the anti-dither time is out.

Record Delay: System can delay the record for specified time after alarm ended. The value ranges from 10s to 300s

 

[sumguy]

I have no rules set up in the IVS menu.

How can you turn "Smart Plan" on if there are no IVS rules? Or does Smart Plan NOT pertain to IVS rules (and if it doesn't, then what does it pertain to ?)

 

[looktall]

You have to enable the smart plan and then you can create the rules.

 

[wittaj]

If you do not have Smart Plan turned on, then the IVS rules do not work.

You need to enable Smart Plan then set up IVS rules.

That is a budget cam, so you might only have IVS rules available for smart plan.

 

[sumguy]

I see that if I move the mouse over the Smart-plan lightbulb icon, the word "IVS" appears in a box under the lightbulb icon, to tell me (I guess) that Smart Plan must be controlling (enabling?) IVS rules. If I click the light-bulb, I can make it turn orange, or grey. I guess orange is for On? So I can turn it on, even if I have no IVS rules defined? So the "smart plan" being on or off IS ACTUALLY TELLING ME IF MY IVS RULES ARE ACTIVE OR DISABLED?

But I have no IVS rules, so they are not conflicting with my video detection settings. Video detection did not work today, I was snow blowing the parking lot for an hour and it detected nothing. Pisses me off.

 

[wittaj]

You will hate to hear this LOL, but 99.9% of the time it is user error.

Yes, if you are not using IVS rules (tripwire intrusion box, etc.) then whether you have Smart Plan enabled or not is irrelevant. And since that is a budget cam, you would not want it turned on if you are not using IVS rules.

It sounds like you are using simple motion detection.

Are you recording to an NVR or BI or some other VMS or just relying on the camera?

Do you have an SD card in the camera and can see it did or did not trigger?

Did you have MD setup and was the entire field of view boxes indicated and was a schedule set by accident that missed the event.

Are you on default/auto settings or did you dial the camera in to your field of view? Auto/default can struggle in certain fields of view and an all white snow field of view with everything at default 50 can be problematic.

The only way to know for sure if it is user error or a defect in the camera is to post screenshots of every setting in the camera. Otherwise we are just guessing at the issue.

 

[sumguy]

No NVR. Camera has SD card. Simple zone-based video detection only. Camera will send me email and will record to SD card when video detection is triggered.

When I had the camera's IR light on at night, the camera records way way way too many little zippy things, rain, snow, etc. I now have remote-mounted IR light, do not use the camera's IR light. IR light comes on and off based on sunset / sunrise. Camera does detect the IR light coming on and off and does record the event for a few seconds to the SD card and sends email.

I have several zones set up, relatively low threshold. Today it detected me walking in one of the zones (red zone) but did not detect me snowblowing in the other zones (yellow zones). I will have to have someone walking around in the various areas tommorrow in the bright sunlight so I can watch the real-time video detection setting screen and see if the detection spikes cross the threashold line.

I'm not sure what you mean by default / auto settings. I have adjusted the day and night video settings for what (to me) are the best settings (best clarity, contrast, intensity, etc).

 

[wittaj]

Yeah the built-in IR can suck with rain, snow, bugs, etc,. especially on non-AI cameras.

Most of us have found the MD in the cameras to be problematic, so it is why most of us go with cameras with AI and then use IVS rules to knock out those false triggers. Mine didn't trigger during a blizzard except for when a person was in the field of view.

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

It has come to my attention that certain Dahua cameras come with built in AI that distinguishes between human & cars. I was unaware of this. Well, always saw the AI word used in the reviews but never really thought about it because I thought it was a Dahua NVR integration only. I am currently...

ipcamtalk.com

 

[sumguy]

Here's what it did capture today:



But it did not capture when I was using the snow blower (in the central area of the image, the parking lot). Here is the zone detection pattern:



The red zone detection threashold is set a little bit more sensitive than the yellow zone.

Red zone sensitivity is 74, threshold is 16. For yellow zone the numbers are 67 / 31.

 

[bigredfish]

I havent used MD or SMD in many years. (Except for nighttime LPR where the scene is completely black to pick up car head/tail lights)
AI/IVS is so much better its the difference between a 1970's calculator and a modern laptop.

MD works by sensing the change in pixels. Too much or little contrast and it fails. Sensitvity would probably need to be higher in the 85-90 range to pick up a difference in that very bright white FOV. Of course then you'll also get more false alerts.

IMHO you should dump MD and start learning about IVS

 

[tigerwillow1]

Pulling from memory (i.e. not guaranteed correct), record delay is how long the recording will run after an event trigger. Doesn't matter much if you're doing 24x7 recording. Anti-dither is a lockout period after an event trigger, where another trigger will be ignored. The purpose is to avoid multiple, closely spaced event triggers. Stated in chinglish:
System only memorizes one event during the anti-dither period. The value ranges from 0s to 100s.

 

[zexoni70]

In the motion detection settings, I have anti-dither set to 2 (it cam be 0 to 100 seconds) and I have record delay set to 10 (it can be 10 to 300 seconds, so I have it set to the minimum).

Here you have everything nicely explained about (Anti-Dither, Pre-Record, Record Delay, Pack Duration...) settings!

Recording Variables (Anti-Dither, Pre-Record, Pack Duration etc) - Providing A Rundown of What They & Others Do & How They Work

All, i’ve been asked by many recently to help explain the various recording related verbiage / variables featured in cams and specifically the Dahua NVRs. I’ve also received and seen a lot of questions / posts about Motion Detection, specifically ‘why is Motion Detection performance poor, why am...

ipcamtalk.com

 

[sumguy]

I'm just going to keep trying the basic video detection. What I've discovered is that I seem to have to set the sensitivity to 100% and the threshold to 10% to capture someone walking in the red zone. The camera is about 15 feet from ground level, and the distance involved in the path beside the building is like 75 ft, so detection ability changes quite a bit from far to near. This would explain why there was no detection in the yellow zone - I'd have to set that also to 100% and drop the threshold way down.

This is I think a wide angle lens, and the total area I'd like to cover could be 100 ft from the camera. A car, especially at night with lights, will be easy, but a person at anything more than 50 ft at night, probably not. Anyone here think that IVS can do it? If so, what sort of detection rule?

 

[wittaj]

IVS could do it, but at the same time you have to be careful of trying to do too much with one field of view.

Try IVS rule with an intrusion box and then with a zigzag tripwire and see which one performs better.

100 feet for a 2.8mm fixed lens is difficult, especially at night and even more so for a 4MP on a 1/3" sensor that was designed for 720P - the sensor just cannot get enough light at night.

Here is the Detect, Observe, Recognize, and Identify number for the camera:



This is best case, ideal situations.

Most of us will say you have to probably cut those numbers in half for realistic numbers during the day, and then take that number cut in half and cut in half again for night time.

 

[Flintstone61]

These cam menus that only have an option for recording delay seem goofy to my mind,,,,i would think you'd want to set Pre-event record in seconds so you can see the things leading up to the trigger. I've never understood the choice of record delay....

 

[sumguy]

My camera (2431T-AS-S2 ) has anti-dither and recording delay - no other time-related settings for video detection. Anti-dither is set to 2, recording delay is the minumum (10). Looking at some recent lightning detections, all recordings are about 15 or 16 seconds in length, with 3 seconds of recording before the lightning.

The email with image that is sent does not seem to be the actual frame that triggered the detection, perhaps it's the first frame in the sequence (about 3 seconds before the lightning?).

 

[looney2ns]

As others have stated, if you stop using motion detection, and use IVS instead, you will get MUCH better results, with very few false triggers.