COLOUR COR­REC­TION

See­ing in colour is not a black-and-white busi­ness, ad­vises Derek Pow­ell, dis­cov­er­ing how Sam­sung is help­ing peo­ple with colour blind­ness to see true blue (as well as true reds and greens).

Sound+Image - - Contents - Derek Pow­ell

Some lev­els of colour blind­ness can now be fixed by your tele­vi­sion.

Colour blind­ness is the um­brella name for a range of con­di­tions that af­fect a sur­pris­ing num­ber of peo­ple. Many in­di­vid­u­als with mod­er­ate forms of this con­di­tion re­main un­di­ag­nosed, and there is cur­rently no treat­ment for in­her­ited colour blind­ness. But two re­cent tech­nolo­gies are of­fer­ing fresh and sur­pris­ing pos­si­bil­i­ties — a new win­dow on the world for those with this con­di­tion.

In Aus­tralia, around one in 12 men and one in 20 women will have some im­pair­ment in their abil­ity to dis­tin­guish the full range of colours. World­wide, it is es­ti­mated that around 300 mil­lion peo­ple may have colour vi­sion de­fi­ciency (CVD). CVD can pre­vent peo­ple from en­ter­ing cer­tain pro­fes­sions — pi­lots and com­mer­cial driv­ers, for ex­am­ple, need to be able to in­ter­pret colour cor­rectly to re­act to ev­ery­thing from traf­fic lights to cock­pit warn­ing in­di­ca­tors; they com­monly have to pass a colour blind­ness test be­fore re­ceiv­ing a li­cence. Elec­tri­cians also need to be able to ac­cu­rately dis­cern ac­tive, neu­tral and earth wires based on colour alone, and there are a num­ber of other roles in the armed forces where lives can be in dan­ger if peo­ple can­not cor­rectly recog­nise ob­jects or in­di­ca­tors based on colour alone.

Our modern re­liance on screens in ev­ery­thing from phones and com­put­ers to mul­ti­func­tion dis­plays in ve­hi­cles has broad­ened the range of sit­u­a­tions in which colour per­cep­tion dif­fi­cul­ties can cause prob­lems. The in­abil­ity to ac­cu­rately per­ceive hues can make it hard or im­pos­si­ble to dis­cern some shades of text over coloured back­grounds on screen. Sim­i­larly, in­ter­pret­ing coloured graph­ics and nav­i­gat­ing var­i­ous user in­ter­faces can be quite dif­fi­cult.

For­tu­nately, some of these same screens, on smart­phones and TVs, are now able to make life a lit­tle eas­ier for those with colour vi­sion de­fi­cien­cies. Colour con­ing This is achiev­able be­cause the way our eyes per­ceive light has many sim­i­lar­i­ties to the way that colour dis­plays work. In the eye, there are two types of sen­sors that re­act to light. Rod cells are quite sen­si­tive, and re­act like

black-and-white film, see­ing the world in shades of grey. Cone cells are our eye’s colour sen­sors and are of three types, sen­si­tive to red, green or blue light re­spec­tively. Our brain uses the sig­nals sent by the dif­fer­ent cone cells to dis­tin­guish the colour of ob­jects. A red ob­ject will pri­mar­ily stim­u­late the red­sen­si­tive cones; a yel­low ob­ject will pro­duce a nearly equal stim­u­lus in both the red and green cones, and so on. The eyes have it Nor­mal colour vi­sion is called trichro­macy, where the three types of cones op­er­ate cor­rectly to ac­cu­rately dis­tin­guish the range of hues from reds through greens to blues.

Anoma­lous trichro­macy oc­curs when one type of cone has a re­duced sen­si­tiv­ity. A re­duced sen­si­tiv­ity to green light (known as

deuter­a­nomaly) is the most com­mon form of colour blind­ness; with re­duced sen­si­tiv­ity to red ( protanomaly) the next most com­mon.

Tri­tanomaly, re­duced sen­si­tiv­ity to blue light, is the third form, and is com­par­a­tively quite rare. The amount of re­duced sen­si­tiv­ity can

vary quite a lot, rang­ing from al­most nor­mal colour vi­sion to cases where the per­son can­not at all per­ceive light in the red or green or blue parts of the spec­trum. Like the eye, a colour video cam­era has red, green and blue sen­sors, with the whole range of colours re­pro­duced on screen by emit­ting more or less light from red, green and blue pix­els, nor­mally balanced to pro­vide proper colour re­pro­duc­tion. To a cer­tain ex­tent you can sim­u­late the ef­fects of protanomaly, deuter­a­nomaly and tri­tanomaly by go­ing into the menu of a com­puter mon­i­tor and turn­ing down re­spec­tively the red, green and blue chan­nels. Pre­sum­ing you have nor­mal colour vi­sion, if you turn down the red, the re­sult­ing pic­ture will look some­thing like the world view of some­one with protanomaly. Turn­ing the red right off would some­what sim­u­late the con­di­tion of protanopia, the con­di­tion where the per­son’s red cones are ab­sent al­to­gether (the re­sult­ing spec­trum cor­re­sponds to the colours in the largest cir­cle above left). I don’t want to push this anal­ogy too far, since colour vi­sion de­fi­ciency can be much more com­pli­cated, but it is use­ful to un­der­stand the pos­si­bil­i­ties that tech­nol­ogy can now bring. Most peo­ple are able to func­tion re­ally well with mild or mod­er­ate colour blind­ness, and many re­main un­aware of the lim­i­ta­tions in their own vi­sion. Proper di­ag­no­sis in­volves a va­ri­ety of tests, of­ten in­clud­ing the Ishi­hara Plate test. This test uses spe­cially printed graph­ics with a back­ground of coloured dots that con­tain num­bers picked out in dif­fer­ent hues (right). Peo­ple with var­i­ous types of colour vi­sion de­fi­ciency will be un­able to make out cer­tain of the coloured num­bers against par­tic­u­lar back­grounds.

Vi­sion of the fu­ture

To be use­ful, the printed graph­ics must have ex­tremely ac­cu­rate colour print­ing. Gen­er­ally, un­cal­i­brated colour mon­i­tors couldn’t be guar­an­teed to re­pro­duce these graph­ics with suf­fi­cient ac­cu­racy for a re­li­able test. But the new­est tech­nol­ogy smart­phone screens can be man­u­fac­tured to such pre­cise tol­er­ances that they can re­pro­duce Ishi­hara-style graph­ics closely enough to pro­vide a use­ful (though not fully di­ag­nos­tic) test for colour vi­sion de­fi­ciency. A cou­ple of apps have been de­vel­oped to help ad­dress CVD for phone and com­puter users (in­clud­ing the use­ful Color Blind Pal for An­droid, iOS and Mac). Then late last year Sam­sung an­nounced that it has gone even fur­ther, bring­ing this tech­nol­ogy to a much larger can­vas.

Sam­sung has taken a very sci­en­tific ap­proach here, work­ing with Pro­fes­sor Klara Wen­zel from the Depart­ment of Mecha­tron­ics, Op­tics and Me­chan­i­cal En­gi­neer­ing In­for­mat­ics at the Bu­dapest Univer­sity of Tech­nol­ogy and Eco­nomics. Pro­fes­sor Wen­zel leads a team that de­vel­oped Colourlite Test to ac­cu­rately di­ag­nose the kind and de­gree of CVD.

Work­ing with Sam­sung, the Color­lite team adapted the test* to be­come an app that can be used on any Sam­sung Gal­axy Note 6 (or later) mo­bile phone. It is called the ‘SeeColors’ app, and it is able to di­ag­noses de­fi­cien­cies in colour vi­sion on-screen. The app was first re­leased some time ago to Hun­garia, Ro­ma­nia and Bul­garia but is now avail­able more widely, in­clud­ing via down­load through Sam­sung’s ded­i­cated App Store, thereby open­ing up a new and amaz­ing pos­si­bil­ity for those with CVD to ex­pe­ri­ence true colour vi­sion for the first time — on their tele­vi­sion. Here’s how it works. First, the user runs the app on-screen and takes the test, re­spond­ing to each of the graph­ics that ap­pear. Once com­plete, the app pro­duces a per­son­alised re­sult that records the type of de­fi­ciency (such as deuter­a­nomaly, protanomaly or tri­tanomaly) and, cru­cially, gives a num­ber which sig­ni­fies the de­gree of im­pair­ment. In the next step, the user can in­struct their Sam­sung TV to re­cal­i­brate the screen, ad­just­ing the colour bal­ance to pre­cisely coun­ter­act the de­fi­ciency re­vealed by the test. If the test in­di­cates a re­duced sen­si­tiv­ity to red, *You can try out a sim­pli­fied form of this test on­line via www.avhub.com.au/color­lite for ex­am­ple, the screen will boost the red hues to pre­cisely com­pen­sate for the lack of sen­si­tiv­ity in the per­son’s red cones, re­veal­ing a range of hues that they just couldn’t dis­cern oth­er­wise.

It is a lit­tle more com­plex that my de­scrip­tion would sug­gest, but still, the idea is so sim­ple that you might well ask why has no-one thought to do this be­fore. There’s a very good rea­son. Turn­ing up the red chan­nel of an or­di­nary TV or com­puter mon­i­tor will sim­ply sat­u­rate that chan­nel, crush­ing the con­trast with­out mak­ing colours brighter. With con­ven­tional screens, the RGB chan­nels nor­mally work near their max­i­mums. While the colour chan­nels can eas­ily be turned down, they sim­ply don’t have the dy­namic range to be made sig­nif­i­cantly brighter. But the higher ‘nit’ lev­els of to­day’s high dy­namic range (HDR)-ca­pa­ble TVs, such as Sam­sung’s QLED range, do have the bright­ness in re­serve on each colour to be turned up far enough to make a dif­fer­ence.

But does it work? I can’t eas­ily tell, as I have nor­mal colour vi­sion, so I called a con­tact at Sam­sung Aus­tralia. We were told that the app had caused some ex­cite­ment in their of­fice, with a pair of brothers who suf­fered from the com­mon red-green colour vi­sion de­fi­ciency vol­un­teer­ing to try it out. They both re­ported ex­cit­ing re­sults, com­ment­ing that the cor­rec­tion made a great dif­fer­ence to their view­ing ex­pe­ri­ence, even mak­ing faces clearer due to the im­proved skin tones.

There are a cou­ple of lim­i­ta­tions, of course. The app needs an HDR TV with QLED tech­nol­ogy to op­er­ate, and it won’t help some­one who has a com­plete ab­sence of red, green or blue cones — though thank­fully that is a rel­a­tively small pro­por­tion of those with CVD. Also, the re­cal­i­bra­tion is, of course, re­ally only use­ful for solo view­ing. Once ad­justed for some­one with sig­nif­i­cant CVD, the pic­ture will look ap­palling and un-nat­u­ral to some­one with nor­mal vi­sion.

De­spite these nig­gles, here’s a re­ally good story of how modern dis­play tech­nol­ogy, de­signed to make things a lit­tle more real for ev­ery­one, can open a truly amaz­ing win­dow on re­al­ity for mil­lions of peo­ple with CVD.

TRUE COLOURS: the cir­cles rep­re­sents the colour spec­tra per­ceived by peo­ple with nor­mal vi­sion (le), protanopia (large cir­cle), and tri­tanopia (bot­tom). RIGHT: Sam­sung’s ‘SeeColor’ app.

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.