a metric to evaluate the closeness of the two colours · colours that give the similar impression....

Ametrictoevaluatetheclosenessofthetwocolours

YasukiYamauchiYamagataUniversity

Referencecolourb*

a*

Selectedcolours

Task:"Findtheclosestcolouronaline(e.g.equalsaturaDon)"

Selectedcoloursarenotalwaysthecoloursofmin.ΔE

Coloursofmin.ΔE

CPRC1

CPRC7

ThesizeoftheColorGamutsaredifferent

CPRC1

CPRC7

Whenwewouldliketomapasourcecolortoacolorinagivengamut,weneedtofindthe"corresponding"color(=perceptuallyequal).

Sourcecolor

Closestcolors

AQercollecDngseveralclosestcoloursofdifferentgamuts:

Referencecolour

Trendofthecoloursselectedas"closest"tothereference

b*

a*ConsistentColors

Coloursthatgivethesimilarimpression

EvaluaDonofatestcolour:"howclosetothereferencecolour"

Referencecolourb*

a*

Hypothesis:Wedon'tcalculatethecolourdifferencedirectlybetweenatestandthereferenceEvaluatewiththedifferencefromthetrendoftheconsistentcolour?

Ametrictoevaluatehowcloseagivencolourtothereferencecolour

Referencecolourb*

a*

Findthecorrespondingtrendcolourandcalculateitsdifference(closeness)

Conceptofthecolordifferencebasedonconsistentcolorlocus

Step1:Findthetrendlines (consistentcolorloci)

Step2:Findthe"distance"ofatestcolor fromatrendline

Experiment

Gamutsusedintheexperiment

12targetcolors(references)

ConfiguraDonofthesDmulusTestcolorchangedalongthesurfaceofagivengamut

Consistentcolorloci (forCRPC7,CRPC5,andCRPC3)

b*

a*

Testcolor Referencecolor

1:Findthecorresponding"consistentcolor"

EvaluaDonofthecolor(1)

CRPC5CRPC3 CRPC7

SDmulusconfiguraDon

EvaluaDonofthecolor(2)

Howfaristhetestcolorsfromatrend-line