Is this NVR selection satisfying? (Dahua or an alternative) ?
- Thread starter loe22
- Start date
You have exactly what I want to do with having a Z4E zoomed in only on the street. I feel that would be very beneficial! You like it like that?
bigredfish
Known around here
Best thing I ever did.
The frustration for most is that you have your own property covered with good ID choke points, but MOST of the "bad" activity happens at other homes. (simple law of averages)
So having a camera zoomed into the street/sidewalk where you know they have to pass, helps give you that positive ID you cant quite get from the cameras whose primary purpose is to cover YOUR property.
This guy was picked up because of that camera. Driveway camera just wasn't good enough
Same with this guy, tattoos did it
The frustration for most is that you have your own property covered with good ID choke points, but MOST of the "bad" activity happens at other homes. (simple law of averages)
So having a camera zoomed into the street/sidewalk where you know they have to pass, helps give you that positive ID you cant quite get from the cameras whose primary purpose is to cover YOUR property.
This guy was picked up because of that camera. Driveway camera just wasn't good enough
Same with this guy, tattoos did it
For internal ones (only your cars) ivs
For external ones (lots of other cars) full VMD
That’s awesome! And you used video meta data for the captures of those two? That’s where I am, my camera’s are for my property and you have to digital zoom to try to get to street, which obviously is not great. Is the z12e just as capable as the z4e with this? I know the difference in specs just didn’t know being s2 vs s3.
bigredfish
Known around here
Yes thats using VMD on the Z4 zoomed in. That also gives me the AI search on the 5 series NVR
No the 5241-Z12 wont do quite as well as the 5442 Z4 S3
Human, Face, Vehicle, Non-vehicle
No the 5241-Z12 wont do quite as well as the 5442 Z4 S3
Human, Face, Vehicle, Non-vehicle
The Z12E does great for plates at distance, but beyond the distance range of the Z4E, the Z12E doesn't do as well for people.
So either aim for the distance capabilities of the Z4E or don't try, at least in my experiences.
Personally I like to keep the Z4E under 65 feet or so. The Z12E at 80+ struggles for me for people at night.
So either aim for the distance capabilities of the Z4E or don't try, at least in my experiences.
Personally I like to keep the Z4E under 65 feet or so. The Z12E at 80+ struggles for me for people at night.
Thanks for showing me all of this! I am definitely going to do this as I can only imagine how much I miss that’s going on and I’ve already had to give police officers footage 3 times.
So if I’m understanding you correctly, since the Z4E isn’t using OCR, it’s functionally using VMD to capture the “Vehicle” driving by and then in the snapshot (hopefully) you can see the plate (which this can also be done using the Z12). Now the kicker here is if you manipulate the night settings on Z12 to be able to see the plate only, how would the VMD be able to identify the “vehicle” since everything is blacked out but the plate?@camdensnyder
Note that @steve1225 is seeing European plates, which is like 50% cheating compared to US plates which are much harder.
The 5442 Z4E doesnt read plates with OCR so they can't be searched via a database, it simply uses VMD to captured the vehicle and if you happen to have the camera positioned well, you can see the plate and visually identify them as in Steve's example.
Many of us do the same thing with 5241 Z12's and have for years. Like many I have dedicated cameras for LPR, the Z12 mostly. And while the ability for 5 series to "see" the plate is nice, I dont rely on it.
Note about plates using VMD and a 5 series NVR
As mentioned, IF you have the proper focus you MAY be able to visually ID a lot of plates during daytime. But at night, you'll be faced with the plates being blown out due to the far different setting requirements needed to capture plates at night. If you tune your nighttime settings to be able to see the plates, you wont be able to generally see anything else as everything but the plate will be almost black.
View attachment 208469 View attachment 208470
Typical plate capture with a 5241-Z12
View attachment 208471
At day this is simple.
You enable Full VMD (AcuPick disabled) and very short exposure time - and this simply works...
Night conditions are much more complicated. There are two ways of doing thing:
- classical - strong IR + very short exposure time (1/1000 or 1/2000) + HLC + some image settings tuning.
In most cases You will capture car plate + car light, sometimes some shape of the car.
This works much better for the USA car plates (with are big mess for me as person from EU), but due fact camera almost don't see a car VMD or IVS will not work here very well...
- Full double/triple shot WDR (>= 50) + strong IR and longer exposure time (1/200)..
This is used by me.. Full double/triple shot WDR works similar to HDR in other cameras (mobiles, sport cameras, drones). For each frame of video camera is doing two or three shots at different exposure times to capture elements at different brightness and them WDR/HDR algorithm combine them.
if you main/first short is 1/200 (where camera see car details, road, people etc - can be little blurry if they move fast but this is ok) then the second is like 8x faster - so 1/1600 - at this setting camera sees mostly IR reflection from car plates and lights.. Second exposure is fast (1/1600) so the plate is sharp / not blurred.
This technique works very well in EU, where we have unified high contrast stamped and painted using special paint (plate background is reflective, text font is not).
if you see examples below, there is white border around plate (left/down side if we see back of the car, right/top side if we see front of the car). This is results that there are two different shots, one longer before and one shorter after combined in one photo. Between the shots car moves a little, so car plate is always moved one way or another to the car (car position difference between shots).
This is some kind of visual aberration which I see very often on speedy tickets done at night here in EU. We receive BW pictures of full car, plate numbers (with this chroma aberration) and usually even people inside the car.
Chroma aberration around car plate is defect from how WDR works - so this WDR technique is used here in EU frequently. There only one difference is that I use simple IR reflection, street radars are using full spectrum white flash reflection.
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