h a l f b a k e r yWarm and Fussy
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When you're on the open highway, the need to dip your lights with persistent oncoming traffic can be hazardous where the road is unfamiliar, narrow, winding, and/or poorly lit.
With a low-brightness widescreen LCD panel mounted just above your steering wheel (fed by a good IR camera in front), and
combined with regular headlights, the full-beam infrared headlights would allow you to anticipate road hazards beyond a mere 50 feet in front of you.
The obvious problem of oncoming vehicles also fitted with IR headlamps (causing light pollution on your display) might be overcome in this way:
The IR headlamps would consist of LED arrays. These would be strobing at a certain frequency, above the level that humans generally perceive (say 75Hz).
In the event of oncoming IR headlamp traffic, the driver would press a "Change Freq" button on the display unit. Software would change the headlamp strobe frequency to a random rate in a lower range - say, 30-60Hz - only sampling input from the camera CCD when the lamps are in the "on" phase. Provided the electronics in both lamp and camera were of very low latency (is that the word?), this would reduce the amount of interference on both vehicles' displays - especially if both drivers changed to a lower strobe frequency.
The "Change Freq" button would act as a toggle to switch between the normal high freq mode (75Hz) and the random low freq mode (30-60Hz).
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Annotation:
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Another way would be to polarize the headlamps oppposite to the camera polarising filter. |
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I'm quite sure, without looking, that the technique of polarising would have been discussed here previously. |
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Hmm, the thing about polarised lamps and such - on the straights, they'd be fine; but on winding roads, approaching headlights aren't always in the opposite-side field of vision as cars come round bends ahead (but can still temporarily glare your vision). Wouldn't that defeat any filtering? |
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//Wouldn't that defeat any filtering?//
I don't think it would. If windshields and headlamps all have diagonally-oriented polarizing (say, top left to bottom right, as viewed from inside the car) you'd be able to see your own headlamp beams but not those of any approaching traffic.
Regarding this idea, I suspect that IR provides insufficient fine detail to permit safe driving decisions. Also, I wonder whether the frequency differences would cause beat-frequency effects. |
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//frequency differences possibly causing beat-frequency effects//
Probably - I had considered that, but couldn't think of another way of achieving it, not knowing enough about polarisation (obviously) :)
Thanks all for comments. |
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I've actually considered installing this, using an old IR heatlamp, an inverter, and a CMOS video camera. I think the range would likely suck though. |
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The correct arrangement of optics and IR lasers could solve both the range and dazzle problems. Say the emitter is standardized to be lower than eye level (ie at headlamp height), and spillage is minimized by the use of a laser and either lenses or mechanical scanning to produce a tightly controlled beam pattern that stays at or below horizontal. |
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If the camera is placed higher, say above the windshield, that could help too. |
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Still, I guess you could run into trouble on uneven terrain, like coming over a rise. The diagonal polarization thing should work. |
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One wonders just how powerful an IR laser one can obtain on the open market... |
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