All the col­ors of the rain­bow

A break­through by a re­search team in Hong Kong is set to al­low color-blind peo­ple to view al­most nat­u­ral col­ors on screens. Li Yinze re­ports.

China Daily (Hong Kong) - - FOCUS -

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. In­put

The abil­ity to dis­tin­guish 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.

Telling red from green

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 Out­put im­age pair With­out stereo­scopic glasses With stereo­scopic glasses Nor­mal au­di­ence (wear­ing noth­ing) color de­fi­cient au­di­ence (wear­ing glasses) the col­ors peo­ple see. Peo­ple with de­fec­tive vision can­not per­ceive the “just no­tice­able” dif­fer­ences by which col­ors nor­mally are per­ceived.

Al­though there is cur­rently no cure for color blind­ness, the CUHK ap­pli­ca­tion pro­vides color en­hance­ment. The CUHK team de­vel­oped an ap­pli­ca­tion that pro­duces a pair of vir­tu­ally iden­ti­cal images and dis­plays them on the view­ing de­vice. The sep­a­rate images are re-col­ored to em­pha­size the dif­fer­ences.

Ac­cord­ing to the type and sever­ity of the pa­tient’s color blind­ness, each im­age can be re-col­ored into hues and color

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.” Sa­muel Shen Wuyao, com­puter sci­en­tist and mem­ber of a Chi­nese Univer­sity of Hong Kong team who cre­ated an ap­pli­ca­tion that can be in­stalled on reg­u­lar 3D dis­play de­vices to help color blind peo­ple dis­tin­guish col­ors


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

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