Reviewing footage on pc

[Nigel]

Sometimes headlights appear more like in gse's image when HDR is enabled.

Gse’s image is clearly using HDR because it has a readable front panel on the box. Your images don’t have that front panel, so it appears to me that yours did not use HDR for some reason.

 

[Dashmellow]

Gse’s image is clearly using HDR because it has a readable front panel on the box. Your images don’t have that front panel, so it appears to me that yours did not use HDR for some reason.

What I am saying is the HDR has not performed the same way for me, but yes, HDR is indeed enabled in the second image I posted above. As I mentioned earlier in this thread, I've had mixed results with the modified software, some very good and some not so good at all. I've not experienced low light plate capture anywhere near what I've seen posted on the forum.

Just flashed V2.6T today and will see what results I get.

 

[Dashmellow]

OK, here are my first results from V.2.6T. Not so good compared to what has been posted by others. HDR enabled - exposure -1/3 .

As I also mentioned earlier, the size and colors of American and Canadian license plates may make a big difference here.

My windshield is spotlessly clean as is the lens.

There is a lot of blooming and noise on reflections and bright lights. I will explore further and post results as time permits.

This was the best frame.

 

[Kremmen]

Very useful info.

So what is the best FW, stock 1.03, vvs mod or the latest 2.06.

Very difficult to know without this sort of testing.

What I do know from my earlier testing, with my settings, is that HDR 'On' does produce more motion blur on mine. Also, scrutinising my footage, EV -1/3, in daytime, turns darker areas like roadside tree hedges into very dark areas. EV 0 and you can see far more detail. EV - 1/3 seems like dropping a slightly tinted lens across.

 

[HonestReview]

Agree with this, no dashcam would catch that plate without using HDR and there is no evidence of HDR being used in that video.

I think the speed was probably too high anyway for any current dashcam, but there are improved HDR versions coming.

This dashcam probably needs a firmware update to enable the HDR, probably worthwhile with winter approaching in the UK.

So should HDR always be enabled on a Dash Cam??? How does HDR work exactly and will it affect image quality (for the worst)?

 

[Kremmen]

Isn't it odd that in my testing HDR made it worse by introducing more motion blur !

 

[Dashmellow]

Here are several new screen shots from last nights initial test with V.2.6T.

Plates are captured with HDR enabled but not readable and there is severe blooming, noise and haze around each vehicle. There is even a halo around one vehicle's headlights. I will double check to make sure there is no issue with a smudged lens or dirty windshield. These were captured on a pitch dark rural road with no other lighting than the car headlights.

So far, V.2.6T compares unfavorably to the other mods I've tried but none have been able to adequately capture plate numbers at night.

I'll will disable HDR on V.2.6T and see what happens going forward.







As a control, here is a screen grab at the well illuminated gas station/convenience store I stopped at before heading home when the above images were captured.

 

[Kremmen]

On that last shot you have tested a partially lit rear plate but someone put a post in the way

 

[Dashmellow]

On that last shot you have tested a partially lit rear plate but someone put a post in the way

I wasn't thinking about the plate number when I posted that particular image. It was merely to demonstrate a clear image from the same footage with no blooming, noise or haze when under bright illumination.

 

[Nigel]

So should HDR always be enabled on a Dash Cam??? How does HDR work exactly and will it affect image quality (for the worst)?

With the current HDR, some people like it, others don't, and it seems the results vary quite a bit between different people.
No dashcams so far seem to have got a good HDR working in all situations, and in any case it is never going to produce perfect results because of the way it works.

So try it and see if it works for you, if it does, use it, if it doesn't, that is unfortunate, simply turn it off again.

It does seem to be more use in dark conditions, especially if you have bright headlights and your plates use reflective backgrounds, which is why I said "probably worthwhile with winter approaching in the UK."

How does it work? well there are multiple designs that don't all work the same way, but basically every frame is a result of two exposures, a short one that has correct exposure for reflective number plates and a long one that has correct exposure for the shadows, the two frames are then combined by some algorithm that tries to use the short exposure for areas that where very bright and the long exposure for areas that were in the shadows, so the result should be good exposure everywhere across the image. It is not actually that easy though, and you get problems such as when plates are non-reflective they are not bright enough to trigger using the short exposure, and so they become unreadable due to the long exposure time used for that part of the image, which could be the problem Dashmellow is having, I don't think that description is very accurate for the A119 V3 HDR, but that is a good way to think about it, and some cameras use several exposures per frame.

 

[Dashmellow]

It is not actually that easy though, and you get problems such as when plates are non-reflective they are not bright enough to trigger using the short exposure, and so they become unreadable due to the long exposure time used for that part of the image, which could be the problem Dashmellow is having.

Vermont license plates are green with reflective white letters and numbers which one might think should be ideal for night time HDR plate capture but so far, not so much. I happen to live adjacent to two other states, New Hampshire, that has reflective white plates with green lettering and Massachusetts that has reflective white plates with blue lettering and we see a quite a few cars from there as well here (including in the above images - bottom image is a VT plate) but capturing their plates seems not much different with this particular firmware so far.

 

[Kremmen]

That comment about HDR producing a double exposure is where I think my daylight motion blur came from.

As I've posted before, I often use dashcam freeze frame to post new types of UK speedcams I spot as part of my volunteer verifier on PocketGPSWorld.

New speedcam types aren't that frequent and I was quite happy driving round using firmware 2.00 @ 60fps because the video was smoother, in my eyes, than 30fps........until........I tried a screen grab and it was hopeless.

I pass the new camera weekly so, after reading tips here, I tried HDR @ 30fps and that was no better. I then tried HDR off @ 30fps and that was better but not perfect.

I was then contacted by those kind people at Viofo who must have been watching my postings and they sent me 1.03, with an explanation. Installing 1.03 @ 30fps and the freeze frame was almost pin sharp.

Just out of curiosity I installed vvs based on 2.05 and that also produces good daytime freeze frame, HDR off @ 30fps but with better colour so I've stuck with that.

Now that my weekly journeys start in darkness I really must install 1.03 again and see how that compares under LED headlights in the dark.

 

[Nigel]

Massachusetts that has reflective white plates with blue lettering and we see a quite a few cars from there as well here (including in the above images - bottom image is a VT plate) but capturing their plates seems not much different with this particular firmware so far.

I would expect that to work fine, my comment was based on the plates in your images all being too dim to be considered highlights. Possibly your reflective plates reflect a lot less light than european ones, but that seems unlikely, presumably they are all retro-reflective plastic and not pressed metal plates with reflective paint?

There does seem to be an exposure issue in your images too, the dark areas in your last set of images are a long way from black and seem very noisy compared to those from other cameras, but not many people are posting images that don't have streetlights, and your very last image which does have some lighting looks fine. I doubt that is affecting the performance of the HDR though, just looks like Viofo haven't calibrated this firmware for use in full darkness with no streetlights, not easy for them as they live in a brightly lit city, you could point that out to them and maybe they will give you a better calibrated firmware to test out in your lighting conditions.

 

[Kremmen]

I remember watching a documentary program about Police tactics. One of the programs showed a speedcam shot where the owner had installed these anti-flash plates that are normally impossible for speedcams to read, especially at night, so they fit them and speed through cameras.

The operator then just flipped the image into negative mode and there was the number, plain as day - gotcha

 

[Nigel]

The operator then just flipped the image into negative mode and there was the number, plain as day - gotcha

If only it was as easy in real life as in reality show fiction!

 

[Kremmen]

No, this wasn't a reality show as such.

It was a factual program inside one of the police check rooms where operators check the 2 photos before sending out the NIP. I seem to recall in one instance they showed officers attending the registered keepers address and confiscating the plates which added to the speeding offence.

 

[Dalevw]

Morning all. I've just took some images from the settings on my partners dash cam . Please view and advise thanks

Sent from my SM-G991B using Tapatalk

 

[Kremmen]

Glad you installed 1.03 OK

All I've got different is bitrate on high.

Other than that - spot on

 

[Dalevw]

That's how it came. I've not done anything to it

Sent from my SM-G991B using Tapatalk

 

[Dalevw]

Glad you installed 1.03 OK

All I've got different is bitrate on high.

Other than that - spot on

That's how it came. I've not done anything to it

Sent from my SM-G991B using Tapatalk

I've also tipped the cam down one click. I'll review footage from the same road , same conditions in a few days

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