Help­ing You See

How ad­vanced au­to­mo­bile light­ing and op­ti­cal tech­nol­ogy help you see what’s ahead of you.

HWM (Singapore) - - LEARN - TEXT // KENNY YEO

Driv­ers need all the help they can get when driv­ing at night, and in poor driv­ing con­di­tions such as in fog and heavy rain. Learn how ad­vances in light­ing and imag­ing tech­nol­ogy are help­ing driv­ers see far­ther, clearer and bet­ter.

1.

HALO­GEN >> XENON >> LED

A car’s head­lamps are the most ba­sic tool that it has to help you see in the dark and in poor con­di­tions such as fog or heavy rain. To­day, the most preva­lent light­ning tech­nol­ogy is the halo­gen lamp, which is es­sen­tially a long-last­ing, brighter ver­sion of the light bulb that Thomas Edi­son in­vented. It is widely used be­cause of its com­pact­ness, sim­plic­ity and long life­span - of­ten up to a thou­sand hours.

Over two decades ago, BMW was the first au­tomaker to make use of xenon or high-in­ten­sity dis­charge head­lamps. In­stead of a fil­a­ment, these head­lamps use two elec­trodes in­side a tube that is filled with xenon gas, va­por­ized mer­cury and metal halides. A spark is cre­ated upon startup and the re­ac­tion in­side cre­ates a bright white light. Xenon head­lamps are fa­vored be­cause of their longer life­span, bet­ter ef­fi­ciency and bright­ness. How­ever, they are costly to im­ple­ment and are so bright that they can some­times blind on­com­ing traf­fic.

The lat­est in head­lamp tech­nol­ogy is LED lights, which was first used on a Lexus in 2008. They are fa­vored by au­tomak­ers be­cause of their com­pact size and ex­tremely low power con­sump­tion, even if they are not as bright as xenon head­lamps. How­ever, LED-based head­lamps are costly to im­ple­ment be­cause they are sen­si­tive to high op­er­at­ing tem­per­a­tures and there­fore re­quire some kind of heatsink to help dis­si­pate heat and op­er­ate re­li­ably. Hence, they are of­ten only in a limited scope such as for turn sig­nals, brake lamps or day­time run­ning lights.

2.

ADAP­TIVE HEAD­LAMPS Adap­tive head­lamps are tech­nolo­gies that dy­nam­i­cally ad­just the car’s head­lamps to im­prove vis­i­bil­ity in poor driv­ing con­di­tions. One ex­am­ple of this are self-lev­el­ing head­lamps that keep head­lamps pointed on the road us­ing sen­sors that can tell whether the car is tilted for­ward or back. This is use­ful in sit­u­a­tions when a car drives over a large bump and causes the head­lights to point up­wards and into on­com­ing traf­fic.

A more ad­vanced form of this tech­nol­ogy can be found in BMW cars. Aptly called “Adap­tive Head­lights”, cars fit­ted with this sys­tem can cast their beams in the di­rec­tion of the curve to pro­vide bet­ter vis­i­bil­ity when driv­ing in the dark or in poor con­di­tions on wind­ing roads. This is achieved by us­ing sen­sors that mea­sure speed, steer­ing an­gle and yaw. Audi has a sim­i­lar sys­tem that uses GPS tech­nol­ogy to pre­dict and start il­lu­mi­nat­ing turns and cor­ners even be­fore the driver turns the steer­ing wheel.

3. NIGHT VI­SION AND OB­STA­CLE DE­TEC­TION One of the most re­cent in­no­va­tions to car safety are night vi­sion cam­eras, which help driv­ers see bet­ter at night, on poorly-lit roads or in ad­verse weather con­di­tions. They can even be used to spot and high­light po­ten­tial dan­gers and ob­sta­cles.

Such sys­tems come in two forms and are ei­ther ac­tive or pas­sive, us­ing ei­ther in­frared or ther­mo­graphic cam­eras. In­frared cam­eras are con­sid­ered ac­tive be­cause they illuminate the road ahead with in­frared light that is in­vis­i­ble to hu­mans. On the other hand, ther­mo­graphic cam­eras are con­sid­ered pas­sive be­cause they cap­ture ther­mal ra­di­a­tion that is emit­ted by ob­jects. The cap­tured footage is then dis­played ei­ther on the in­stru­ment clus­ter or on the wind­screen via a heads-up dis­play. It can then send both vis­ual and au­dio warn­ing cues to the driver.

Com­pared to ther­mo­graphic cam­eras, in­frared cam­eras of­fer higher res­o­lu­tion im­ages, but suf­fer from shorter range and do not work well in rain and fog. On the other hand, ther­mo­graphic cam­eras can of­fer up to 50% greater range, en­abling them to work ef­fec­tively up to 300 me­ters. They are also es­pe­cially ef­fec­tive at cap­tur­ing liv­ing ob­jects, since they emit a heat sig­na­ture. On the flip side, since they rely on de­tect­ing heat sig­na­tures, they work poorly in places with warm cli­mates. Ad­di­tion­ally, the im­ages they pro­duce are of­ten less sharp, and they re­quire a large sen­sor which makes in­stal­la­tion and im­ple­ment­ing them into de­signs tricky.

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