Technical Question About LIDAR, Headlights, and Veil

[JDS]

Technical question for the Veil Guy:

Does LIDAR reflect off of the surface of the headlights, or the reflectors inside? I assume it's the former, but I'm not sure. Or is it both?

[Veil Guy]

The headlight housings of either glass of plastic are primarily transmissive in nature.

Veil Guy

[jdong]

Technical question for the Veil Guy:

Does LIDAR reflect off of the surface of the headlights, or the reflectors inside? I assume it's the former, but I'm not sure. Or is it both?

The inner reflectors are parabolic mirrors that are great at reflecting back light. Of course, if your headlight itself is shiny and reflective (some of them are), then sure it can reflect some LIDAR too.

[insertquarter]

The headlight housings of either glass of plastic are primarily transmissive in nature.

Veil Guy

Sad That I Have 2 Ask Thiz, But in English?

[jdong]

The headlight housings of either glass of plastic are primarily transmissive in nature.

Veil Guy

Sad That I Have 2 Ask Thiz, But in English?

Transmissive: of a transmitting nature.

The clear housing of the headlight primarily lets light, including LIDAR, pass right through it. It neither reflects nor absorbs significantly.

[insertquarter]

Thank u Kind Sir...

[JDS]

Okay, this leads to my second question.

Many people on the VW forums do a "Joey Mod" on their headlights...that is, they black out all the extra shiny parts on the inside of their headlights except for the reflectors themselves. This particularly works with xenon headlights that have more wasted space within the housing, whereas the stock lights take up most of the housing with a large main parabolic reflector.

Would such a modification reduce the range at which LIDAR can get a reading? This assumes a black car with no front plate. In my case, it also assumes VEIL on the headlight housing.

[Veil Guy]

JDS,

Would you provide me with a link or two with a PIC to such a modification?

Veil Guy 8)

[TSi+WRX]

Even the relatively small reflector surfaces behind/within typical "projector" headlamp assemblies - be it HID (aka "Xenon") or traditional incandescent - will reflect visible light to a great degree.

It may not seem so to the naked eye, because of the projector lens being in the way, but a recent set of visible-spectrum pictures by a fellow Subaru owner showed rather shocking reflections from the projector housing of his '06 STI. Search around on this sub-Forum, you should be able to find his post, which also shows his excellent VEIL application technique!

One thing that helped reduce this reflection was the presence of a VEIL-treated "over-lens" that's located farther away from the projector lens. His headlight assembly, which used such a setup, was seen to be much less reflective than that of his fog-lights, for which the over-lens was essentially placed directly above the projector lens, in close proximity.

Exactly how this will translate to the all-critical IR-spectrum, I honestly do NOT know. :oops: :( Hopefully, The Veil Guy can chime-in on this one. :)

However, I view projector lenses as a liability, particularly if they're "naked."

Thus, even if such blacking-out of the surrounding un-used "cosmetic" reflector elements is accomplished (this is a very, very trendy mod in the Import Sport-Compact community now, BTW) - and even if that does help - the extent to which it helps may still be compromised due to the physical setup of the headlamps.

[holein1]

JDS,

Would you provide me with a link or two with a PIC to such a modification?

Veil Guy 8)

Did a quick google search: http://www.peterbeers.net/vw_roadtrip/GTI/GTI_Mods/E-Codes/E-Codes.htm

[Veil Guy]

Thank you holein1.

I suspect this mod would have little impact in contributing to stealth.

Veil Guy 8)

[JDS]

Yeah, that's a great set of photos for explaining the process.

Yeah, I understand that on some headlights, a "Joey" mod only covers up a little bit of chrome and leaves a very large parabolic dish (or two) to reflect laser. However, I'm considering getting lights more in this style, with one xenon housing and one small-ish parabolic dish, which leaves quite a lot of unnecessary chrome (although in this particular photo, it comes "joey modded" from the factory):

http://acekogyo.com/HL/May2007/RSD-103103B.jpg

[Oz Striker]

Or indeed like my black E46 Projectors :D

http://i128.photobucket.com/albums/p183/oz_striker/Temp%20Halo%20and%20Xenon/DSC04431.jpg

http://i128.photobucket.com/albums/p183/oz_striker/Temp%20Halo%20and%20Xenon/DSC04432.jpg


I prefer black anyway, but i also thought that they (along with my smoked indicators) would decrease the range of detection in the same way that a shiny chrome SUV or chrome grill would increase detection range.

[Veil Guy]

Oz Striker,

From one Bimmer owner to another, that is one nice looking ride. :wink:

Veil Guy 8)

[duhtroll]

Mine came smoked from the factory except for the actual HL itself. I'm thinking of VEIL on the inside of the HL cover.

http://i180.photobucket.com/albums/x249/duhtroll/car2-1.jpg

[ELVATO]

That is one shiny Mercury ornament. That could be a problem.

[JDS]

Yeah, I'd black that out if I were you. Just get some Duplicolor or something...

[duhtroll]

Actually, that emblem is long gone as the pic is a few years old. That was the day I took delivery. I have replaced the emblem with one that has a lot more black to it and is less reflective.

[ELVATO]

Good to know :)