All the col­ors of the rainbow

China Daily (Canada) - - HONG KONG -

The color blind Aussie busi­ness­man was com­pletely un­pre­pared for what hap­pened when he walked into the elec­tron­ics fair and donned a pair of spe­cial glasses. For the first time in his life he could dis­tin­guish the col­ors red and green. Peter Mar­ragg has suf­fered from color blind­ness all his life.

What made the ex­pe­ri­ence even more im­por­tant to him was the knowl­edge that from now on he could see those col­ors through the glasses, while en­joy­ing a movie or a tele­vi­sion pro­gram with his fam­ily, who are not color blind.

Com­puter and en­gi­neer­ing sci­en­tists at the Chi­nese Univer­sity of Hong Kong (CUHK) made the break­through that opens up a whole new on­screen world of al­most nat­u­ral color for peo­ple like Mar­ragg.

The break­through comes from ma­nip­u­lat­ing the col­ors that of­ten be­devil color de­fi­cient peo­ple onto two sep­a­rate screens. The col­ors are re­or­ga­nized on those screens to make the color dis­tinc­tions eas­ier to rec­og­nize for peo­ple with color blind­ness. The de­vice has no ef­fect on peo­ple with nor­mal vi­sion. They see the screen as they nor­mally would.

“Red and green used to ap­pear as the same color to me,” Mar­ragg said, “but now I can eas­ily dis­tin­guish the dif­fer­ences.”

The ap­pli­ca­tion, de­vel­oped by com­puter sci­en­tist Samuel Shen Wuyao and his team, can be in­stalled on any reg­u­lar 3D dis­play de­vice. Color blind foot­ball fans now can dis­tin­guish be­tween the col­ors of play­ers’ jer­seys.

The prob­lem for color blind and color de­fi­cient peo­ple be­gins with the light re­cep­tors of the eyes — the rods and cones — which trans­mit in­for­ma­tion from the eyes to the brain.

The abil­ity to dis­tin­guish In­put color re­sides in the three dif­fer­ent types of cones in the hu­man eye. Gen­er­ally speak­ing the cones are sen­si­tive to red, blue and green, re­spec­tively.

Color blind­ness is a con­di­tion usu­ally in­her­ited through a faulty gene in the X chro­mo­some from the mother. Be­cause fe­males have two X chro­mo­somes, they usu­ally com­pen­sate for de­fi­ciency in one, thus the vast ma­jor­ity of peo­ple af­fected by color de­fi­ciency are men.

The prob­lem with color blind­ness is that the light-sen­si­tive cones of the retina func­tion at “be­low nor­mal” sen­si­tiv­ity. Those af­flicted with the de­fi­ciency are un­able to dis­crim­i­nate be­tween col­ors.

The most com­mon type of color blind­ness, for ex­am­ple, is red-green color de­fi­ciency. Some peo­ple suf­fer from blueyel­low color blind­ness. Peo­ple at the extreme end of color blind­ness can see only black and white.

The dif­fer­ent col­ors we see are distin­guished by their wave­lengths on the elec­tro­mag­netic spec­trum, of which the vis­i­ble spec­trum is but a small part. The vari­abil­ity of the wave­length de­ter­mines the col­ors peo­ple see. Peo­ple with de­fec­tive vi­sion can­not per­ceive the “just no­tice­able” dif­fer­ences by which col­ors Out­put im­age pair With­out stereo­scopic glasses With stereo­scopic glasses Nor­mal au­di­ence (wear­ing noth­ing) color de­fi­cient au­di­ence (wear­ing glasses)

The sin­gu­lar im­ages we see com­bine the im­ages picked up by the left and right eye. Seen through a pair of reg­u­lar 3D glasses, each eye of the color blind pa­tient re­ceives only one of the two re-col­ored im­ages. When the im­age is viewed as a sin­gle ob­ject by the brain, color blind peo­ple are able to dis­tin­guish the col­ors.

Shen and his team started re­search on the vis­ual tech­nol­ogy five years ago, when he learnt that color-blind­ness in Hong Kong was much more preva­lent than he be­lieved. Around the globe, it’s es­ti­mated 250 mil­lion peo­ple have color de­fi­ciency.

“A very large num­ber of peo­ple have prob­lems dis­tin­guish­ing col­ors when they do day-to-day work, us­ing com­put­ers, for ex­am­ple, which lim­its their choices of oc­cu­pa­tion,” he said.

To en­able color- blind peo­ple to dis­tin­guish col­ors, sci­en­tists had to un­der­stand how color is per­ceived in the brain and sim­u­late the process. That meant col­lat­ing in­for­ma­tion from a va­ri­ety of color blind peo­ple over a long pe­riod of time.

Shen has ex­pressed his con­fi­dence that the ap­pli­ca­tion can be used in movie the­aters, home tele­vi­sion screens, mo­bile de­vice screens, as well as wear­able equip­ment, and would benefit many in the com­mu­nity.

Many ma­jor cor­po­ra­tions, in­clud­ing Ap­ple and Sam­sung, have ex­pressed their in­ter­est in co­op­er­at­ing with the team, to make it eas­ier for color blind users to see the screen.

“We, as sci­en­tists with rich knowl­edge and ex­pe­ri­ence on color en­hance­ment, should do some­thing to help make a dif­fer­ence,” Shen said.

A very large num­ber of peo­ple have prob­lems dis­tin­guish­ing col­ors when they do day-to-day work, us­ing com­put­ers, for ex­am­ple, which lim­its their choices of oc­cu­pa­tion.”

Con­tact the writer at yinzeli@chi­nadai­


Samuel Shen Wuyao (first right) and his fel­low re­search sci­en­tists.

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