Not so positive review

[Dashmellow]

This one apparently:

https://www.ambarella.com/wp-content/uploads/Ambarella_H22A_Product_Brief.pdf

Thanks Nigel. Here is a screen shot from that processor product brief.

 

[Agie]

It seems to be only for NT98529.

I'm confused as anything. Have the Vantrue N4 Pro and the reflections on licence plates at night are not there like they used to be on older cameras. Is that because of some new technology on the Starvis 2? (That isn't clear HDR)

 

[Nigel]

I'm confused as anything. Have the Vantrue N4 Pro and the reflections on licence plates at night are not there like they used to be on older cameras. Is that because of some new technology on the Starvis 2? (That isn't clear HDR)

I believe they are using the DOL-HDR, which was available on previous sensors, but nobody got around to supporting it on dashcams.

Previous HDR dashcams used inferior HDR that had a time gap between the two exposures which resulted in ghost images, the DOL-HDR doesn't, so there are no ghost images, and that is what makes the difference.

The Clear HDR, if I understand it correctly, does not solve the issue of motion blur at night, only the issue of dynamic range, whereas DOL-HDR does solve the issue of motion blur at night, or at least can improve things considerably. So the Clear HDR is not suitable for night time dashcam use, although it may perform a little better than DOL-HDR during daytime when motion blur is not an issue, which isn't very often when driving!

 

[Paul Iddon]

For all the issues that have been mentioned by various users - there is still no Firmware updates to fix anything - and the lack of support is surprising.

 

[Agie]

For all the issues that have been mentioned by various users - there is still no Firmware updates to fix anything - and the lack of support is surprising.

An enigma nonetheless, maybe these things take time, or it's just radio silence..

 

[Nigel]

An enigma nonetheless, maybe these things take time, or it's just radio silence..

My experience of Vantrue firmware updates in the past has been that they are infrequent and tend to break things! So this isn't too unexpected.
The hardware tends to be pretty good, but I suspect it is going to take a little bit of patience to get good firmware...

 

[LateralNW]

HDR that had a time gap between the two exposures which resulted in ghost images, the DOL-HDR doesn't, so there are no ghost images, and that is what makes the difference.

I'm not sure what's going on with the explanation with HDR and Sony sensor but what you wrote seems opposite to what Sony's blurb says.

From Sony's web site.
DOL HDR

When the digital-overlap (DOL) HDR feature is on, the image sensor captures two images in successionne with a short exposure according to the bright region and the other with a long exposure adjusted to the dark region. HDR is realized by synthesizing these two images to complement one another.

However, this method involves a slight time lapse between the two shots and this can cause some artifacts, such as a blurred outline and chromatic aberration, if the target is in fast motion.

Perhaps your information has come from Viofo who also states that Clear HDR is not ideal for night.

In theory Clear HDR should be the perfect solution. I say in theory as I don't have them to test and am relying on companies telling the truth. (That could explain part of the problem on all sides. )

 

[Dashmellow]

DOL- HDR stands for DOL (digital overlap) HDR. As @LateralNW mentioned it is achieved by combining a short exposure for the highlights and a longer exposure for the shadows superimposed over one another into one image.

This is a technique that has existed for many, many decades back to the days of film based photography. I first learned it when I was a student studying architectural photography in New York City many years ago. It is not only used for increasing dynamic range but also to adjust for complex mixed lighting. You might shoot an exposure with just the incandescent lights in a room turned on using the proper filtration. Then you might shoot an identical double exposure with only the florescent lighting in the room turned on using the appropriate filters. Finally you might shoot a third image with all the lights in the room turned off and only daylight coming in through the windows. In some complex situations like a store or a show room with display lighting and other lighting sources you might have to make additions exposures. If you've done everything correctly you end up with a properly exposed image with all the correct colors. Today, this is still done but digitally instead of on film so you make the color corrections for each exposure in camera instead of using filters and you calculate the exposure according to how many images you need to shoot.

DOL HDR is just a simplified version of this old technique which only involves two exposures, one light and one dark transferred to digital video where it doesn't work quite so well because it involves motion and the two images can be out of register.

Nigel: HDR that had a time gap between the two exposures which resulted in ghost images, the DOL-HDR doesn't, so there are no ghost images, and that is what makes the difference.

So, no Nigel, as @LateralNW says, DOL- HDR is the opposite of that.

DOL - HDR from SONY

 

[viofo]

I'm not sure what's going on with the explanation with HDR and Sony sensor but what you wrote seems opposite to what Sony's blurb says.

From Sony's web site.
DOL HDR

When the digital-overlap (DOL) HDR feature is on, the image sensor captures two images in successionne with a short exposure according to the bright region and the other with a long exposure adjusted to the dark region. HDR is realized by synthesizing these two images to complement one another.

However, this method involves a slight time lapse between the two shots and this can cause some artifacts, such as a blurred outline and chromatic aberration, if the target is in fast motion.

Perhaps your information has come from Viofo who also states that Clear HDR is not ideal for night.

In theory Clear HDR should be the perfect solution. I say in theory as I don't have them to test and am relying on companies telling the truth. (That could explain part of the problem on all sides. )

Because we really did the testing and comparison, so we can make this conclusion.
You can ask Vantrue if they have done any testing with CLEAR HDR.

 

[Nigel]

I'm not sure what's going on with the explanation with HDR and Sony sensor but what you wrote seems opposite to what Sony's blurb says.

From Sony's web site.
DOL HDR

When the digital-overlap (DOL) HDR feature is on, the image sensor captures two images in successionne with a short exposure according to the bright region and the other with a long exposure adjusted to the dark region. HDR is realized by synthesizing these two images to complement one another.

However, this method involves a slight time lapse between the two shots and this can cause some artifacts, such as a blurred outline and chromatic aberration, if the target is in fast motion.

Perhaps your information has come from Viofo who also states that Clear HDR is not ideal for night.

In theory Clear HDR should be the perfect solution. I say in theory as I don't have them to test and am relying on companies telling the truth. (That could explain part of the problem on all sides. )

DOL-HDR does not involve a time lapse between the exposures, the 'O' is for Overlapped, which means the exposures are simultaneous, at least during part of the exposure. One exposure is fast with no motion blur but only able to see the bright areas, the other is slow with motion blur but able to see the dark areas.

Clear HDR has motion blur on both exposures, it can see both bright and dark, but both have full motion blur and thus are no good for reading license plates.
Clear HDR does avoid all the artefacts, except for motion blur.

 

[LateralNW]

Because we really did the testing and comparison, so we can make this conclusion.
You can ask Vantrue if they have done any testing with CLEAR HDR.

Thank you for entering into this discussion.
It was not my intention to attack Viofo but rather suggest another forum user may have misunderstood what Viofo wrote.

I had high expectations of clear hdr thinking it was the solution for Dashcams.

The way i wrote the above was not meant to attack Viofo.

The explanation Sony writes on their web site seems to contradict what another forum user suggests.
So
I contacted Sony recently and am hoping they will reply as I suggested they might be exaggerating what clear hdr does.

I'm happy to ask @Jeff_Vantrue whether Vantrue has done extensive testing on clear hdr.

Just to be perfectly clear I have no gripe with Viofo.

Please pm me if I haven't made it clear.

Cheers

 

[LateralNW]

Clear HDR has motion blur on both exposures, it can see both bright and dark, but both have full motion blur and thus are no good for reading license plates.
Clear HDR does avoid all the artefacts, except for motion blur.

If exposure and shutter speed is poor I'd expect blurring with any camera.
I haven't been wanting license plate reading as a priority.
I just want still images without blurring.

If you're correct then it is disappointing that Sony's clear hdr doesn't work.

I find it interesting Sony says it's suitable for Dashcams.

 

[Nigel]

If you're correct then it is disappointing that Sony's clear hdr doesn't work.

It does work, it is great for movies, but it doesn't do what we want for dashcams.

I find it interesting Sony says it's suitable for Dashcams.

Dashcam | Application | Sony Semiconductor Solutions Group

Sony Semiconductor Solutions Group develops device business which includes Micro display, LSIs, and Semiconductor Laser, in focusing on Image Sensor.

www.sony-semicon.com

They say that this is the result of DOL-HDR, which is what the A229 Pro and A139 Pro are using, but I have never seen these purple/magenta motion artefacts on any Viofo dashcam:

and they say this is the result of Clear HDR, which does look possible, but The A139/A229 Pro give far sharper plate reading using DOL-HDR:

For some reason, they didn't take this image from a dashcam in another car, it is taken from the footpath!

Of course in reality those two images are the same photograph, probably from a tripod mounted DSLR, that has been manipulated into fake images, so you can't trust what they show!

"In general, HDR is realized by capturing a bright and dark image in succession and superimposing one over the other (known as DOL HDR). This method involves a slight time lapse between the two shots, and this can cause some artifacts, such as contour blur and chromatic aberration, if the target is in fast motion (See the image ‘DOL HDR’ below)

This problem is solved by Clear HDR. It can produce both bright and dark images in one shot, and this eliminates artifacts from targets in motion, resulting in a clear HDR image. This is an ideal feature for capturing images of vehicles in motion."

The claim of chromatic aberration on DOL-HDR makes no sense to me, for a colour image sensor, chromatic aberration is purely a lens issue, it has nothing to do with the sensor. The description of DOL-HDR is actually a description of old, pre DOL HDR. The description of Clear HDR is OK, unless you want to read the plates at higher speeds.

If you click on Clear HDR in the quote then the explanation there is OK for Clear HDR, but the explanation of DOL-HDR is still incorrect.

This is a reasonable explanation of DOL-HDR, I think written by Sony when DOL-HDR was new:

Rolling Shutter Image Sensors | FRAMOS

Find an overview of our Rolling Shutter Image Sensors for your vision applications ►FSI CMOS sensors ✓ BSI sensors ✓ STARVIS Technology ✓ Learn more!

www.framos.com

 

[LateralNW]

It does work, it is great for movies, but it doesn't do what we want for dashcams.

Dashcam | Application | Sony Semiconductor Solutions Group

Sony Semiconductor Solutions Group develops device business which includes Micro display, LSIs, and Semiconductor Laser, in focusing on Image Sensor.

www.sony-semicon.com

They say that this is the result of DOL-HDR, which is what the A229 Pro and A139 Pro are using, but I have never seen these purple/magenta motion artefacts on any Viofo dashcam:

and they say this is the result of Clear HDR, which does look possible, but The A139/A229 Pro give far sharper plate reading using DOL-HDR:

For some reason, they didn't take this image from a dashcam in another car, it is taken from the footpath!

Of course in reality those two images are the same photograph, probably from a tripod mounted DSLR, that has been manipulated into fake images, so you can't trust what they show!



The claim of chromatic aberration on DOL-HDR makes no sense to me, for a colour image sensor, chromatic aberration is purely a lens issue, it has nothing to do with the sensor. The description of DOL-HDR is actually a description of old, pre DOL HDR. The description of Clear HDR is OK, unless you want to read the plates at higher speeds.

If you click on Clear HDR in the quote then the explanation there is OK for Clear HDR, but the explanation of DOL-HDR is still incorrect.

This is a reasonable explanation of DOL-HDR, I think written by Sony when DOL-HDR was new:

Rolling Shutter Image Sensors | FRAMOS

Find an overview of our Rolling Shutter Image Sensors for your vision applications ►FSI CMOS sensors ✓ BSI sensors ✓ STARVIS Technology ✓ Learn more!

www.framos.com

I stumbled across this video from Joseph from Blackboxmycar who explains the differences the same way I understand how Clear HDR should work.
Here is the review about Sony Starvis 2 starting where he mentions the HDR abilities.

@BlackboxMyCar

 

[Nigel]

I stumbled across this video from Joseph from Blackboxmycar who explains the differences the same way I understand how Clear HDR should work.
Here is the review about Sony Starvis 2 starting where he mentions the HDR abilities.

He is pretty much reading the Sony explanation, complete with inaccuracies. Doing a really nice job of "reading" it, not his fault it is wrong!

Maybe the biggest error is for DOL-HDR: "This method involves a slight time lapse between the two shots", which is not the case, if you look at the A139 Pro night time images, there is no visible motion gap between the two exposures so clearly no time gap either. It is called Digital Overlap HDR for a reason - the exposures overlap with no time gap.

The other thing to note is that Joseph says that in Clear HDR, the two exposures are simultaneous, he does not say that there is one short one and one long one like in DOL-HDR, in Clear HDR both exposures have the same motion blur, so no sharp images of bright reflective plates like we get with the DOL-HDR, the bright plates have the same motion blur as the darker areas.

 

[viofo]

Thank you for entering into this discussion.
It was not my intention to attack Viofo but rather suggest another forum user may have misunderstood what Viofo wrote.

I had high expectations of clear hdr thinking it was the solution for Dashcams.

The way i wrote the above was not meant to attack Viofo.

The explanation Sony writes on their web site seems to contradict what another forum user suggests.
So
I contacted Sony recently and am hoping they will reply as I suggested they might be exaggerating what clear hdr does.

I'm happy to ask @Jeff_Vantrue whether Vantrue has done extensive testing on clear hdr.

Just to be perfectly clear I have no gripe with Viofo.

Please pm me if I haven't made it clear.

Cheers

I understood that it was not an attack. Maybe I need to explain more in detail.

The clear HDR can help to solve the ghost image that the Sony website mentioned, it is good to use for daytime.
But for night recording, it adds extra noise and is not helpful to get a clearer license plate number.

Some weeks ago, I asked another chipset vendor, they used the STARVIS 2 sensor with their new chipset and implemented the CLEAR HDR.
They told me the night video quality is also not good, too much noise.

There are other solutions for supporting good HDR, maybe in the near future, we can see better HDR performance compared to the STARVIS 2 sensor.

 

[Nigel]

There are other solutions for supporting good HDR, maybe in the near future, we can see better HDR performance compared to the STARVIS 2 sensor.

The DOL-HDR does what we need, it will be very hard to improve.

3 exposure DOL-HDR can probably be an improvement to the image quality, and maybe for plate reading on rainy days and at low speed under bright street lights.

 

[Dex_]

Thanks for explanation. But may be we may use CLEAR HDR for daytime and DOL HDR for nighttime according to HDR timer settings? Because HDR in daytime also useful when moving from dark to bright zones and vice versa but DOL HDR makes ghosts artefacts like in sshot

Spoiler: ghosts in daylight HDR

.

 

[Nigel]

Thanks for explanation. But may be we may use CLEAR HDR for daytime and DOL HDR for nighttime according to HDR timer settings? Because HDR in daytime also useful when moving from dark to bright zones and vice versa but DOL HDR makes ghosts artefacts like in sshot

I think if it is bright enough for Clear HDR to provide no motion blur then it is also bright enough for DOL HDR to provide no motion blur and no ghosts. The clear HDR probably combines the two exposures a little better, but I am not seeing problems with DOL HDR during daylight. I am not convinced that DOL-HDR needs to be turned off during daylight, I have been leaving it on. There may be some differences if you run two cameras side by side with one HDR On and the other HDR Off, but I think those are just exposure differences due to different firmware choices and could probably be fixed.

In your image there is motion blur on the tree, with Clear HDR there would still be the same amount of motion blur on the tree, the motion blur would probably look a little better, but it would still be motion blurred.

 

[Dex_]

I wanna use HDR always ON too. It is not comfortable - manual switch it ON of OFF or customize HDR Timer according to daylight. Now time then daylight rapildy decrease and change HDR Timer setting every week is not comfortable.
But HDR = ON cause blur and not only on trees but on cars too. Now some dashcams have lightsensor for internal cam IR light. May be we also can use it for turn on/off HDR too. Or use Clear HDR if it better for daylight conditions. I just try to find a way use HDR always on and minimize blur.

Spoiler: Full size image from Vantrue N4Pro HDR=ON