NOW YOU’RE See­ing THINGS

THER­MAL IMAG­ING

Cruising World - - Front Page - BY DAVID SCH­MIDT

Early Jan­uary isn’t Puget Sound’s sweet spot, but when one is be­holden to in­vi­ta­tions to sail on other peo­ple’s boats, some­times there’s no choice but to pack a few ex­tra lay­ers, a pos­i­tive at­ti­tude, a pip­ing-hot ther­mos and maybe some­thing a lit­tle stiffer for après-sail time. So when an of­fer came to join some friends for an all-day out­ing that would in­volve a post-night­fall re­turn (read: any­time af­ter 1615 hours at 48 de­grees north) to Seat­tle’s Shils­hole Bay Ma­rina, I packed my warm­est gear and two FLIR hand­held ther­mal-imag­ing cam­eras that I was test­ing, and I did my best to hood­wink my­self into be­liev­ing it wasn’t 27 de­grees when we de­parted.

Flash-for­ward 12 frigid­but-fun hours and the sun had slipped be­low the Olympic Moun­tains as we were search­ing for a chan­nel marker. I grabbed FLIR’S Ocean Scout 640 from my sea bag and, af­ter ad­just­ing color pal­ettes, found the buoy just as things were get­ting frosty. In­stantly, the mood thawed and con­ver­sa­tion quickly piv­oted to din­ner, and a nip of Caribbean rum.

The de­sire to peer through the murk is as aged as the an­cient mariner him­self, and we mod­ern cruisers are for­tu­nate to live in times when off-the-shelf tech­nol­ogy can sig­nif­i­cantly re­duce the stress of night­time nav­i­ga­tion. While ther­mal-imag­ing cam­eras have his­tor­i­cally been ex­pen­sive, this equip­ment af­fords a huge amount of safety and sit­u­a­tional aware­ness, both dur­ing day­light hours and on the grave­yard watch.

Bet­ter still, prices are drop­ping. Here’s a look at how this tech­nol­ogy works, and some ob­ser­va­tions gath­ered while field-test­ing three cur­rent­gen­er­a­tion hand­held de­vices.

Heat of the Mo­ment Ther­mal-imag­ing cam­eras sense minute tem­per­a­ture dif­fer­ences (read: ther­mal ra­di­a­tion) be­tween ob­jects and their back­grounds that are warmer than ab­so­lute zero (a balmy mi­nus-459.67 de­grees Fahren­heit). The cam­eras’ mi­crobolome­ter sen­sors use what they cap­ture to ren­der video im­agery.

For ex­am­ple, FLIR’S ther­mal-imag­ing cam­eras use mi­crobolome­ters that are sen­si­tive to 50 mil­likelvins, or one-twentieth de­gree Cel­sius, to create real-time video im­agery, which is streamed to an in­te­grated or net­worked dis­play, re­quir­ing lit­tle user in­put. Much like dig­i­tal cam­eras, ther­mal-im­age cam­eras come with dif­fer­ent pixel den­si­ties; higher den­si­ties equate to higher-res­o­lu­tion im­agery and bet­ter dig­i­tal-zoom func­tion­al­ity (more on this later).

Most ther­mal-imag­ing cam­eras of­fer dif­fer­ent color pal­ettes (i.e., the set of colors that are used to ren­der an im­age), which al­low the users to tai­lor the imag­ing to dif­fer­ent sit­u­a­tions. When the right color pal­ette is matched with the right at­mo­spheric and view­ing con­di­tions, th­ese pal­ettes high­light ar­eas of con­trast. For ex­am­ple, FLIR’S Ocean Scout 640 hand­held cam­era comes with three pal­ettes, White Hot, Black Hot and In­stalert. “White Hot, where the hottest tem­per­a­tures are white, looks best and in­ter­prets best at night,” says Jim Mcgowan, FLIR’S Amer­i­cas mar­ket­ing man­ager. “Dur­ing the day, I like to flip to Black Hot, which is crisper when things warm up. And if you’re look­ing for crew over­board, In­stalert turns them red.”

To­day’s man­u­fac­tur­ers of­fer a wide va­ri­ety of cam­eras, start­ing with hand­held mod­els that range from $600 to $7,000, all the way up to fixed-mount de­vices that can run any­where from $2,500 to $85,000-plus.

Fixed-mount ther­mal­imag­ing cam­eras are fit­ted in­side small domes that net­work with chart plot­ters or ded­i­cated screens to dis­play their im­agery. Th­ese cam­eras are typ­i­cally weath­er­proof, re­quire lit­tle main­te­nance and

Iris In­no­va­tions’ color pal­ettes let you ad­just to con­di­tions: Black Hot’s good for day­time (top left); White Hot works well at night (above). Red Hot (top right) is use­ful in emer­gen­cies.

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