Color data conversion method, color data conversion apparatus, storage medium, device driver ...

38 Pages·2013·2.3 MB·English

US006611356B1
(12) United States Patent
(10) Patent N0.: US 6,611,356 B1
Shimizu et a1. (45) Date of Patent: Aug. 26, 2003
(54) COLOR DATA CONVERSION METHOD, 6,198,843 B1 * 3/2001 Nakauchi et a1. ......... .. 382/167
COLOR DATA CONVERSION APPARATUS, 6,310,696 B1 * 10/2001 Kumada ................... .. 358/1.9
STORAGE MEDIUM’ DEVICE DRIVER AND 6,323,969 B1 * 11/2001 ShimiZu et a1. ........... .. 358/523
COLOR CONVERSION TABLE
FOREIGN PATENT DOCUMENTS
Inventors: MMaasSaahyi0rS?h iM SOhFimLi ZKlal,n aKgaanwaag a(JWPa) ; sh?ji EP 0 0961488 A3 * 12/1999 .......... .. H04N/1/60
Suzuki, KanagaWa (JP); Satoshi
Semba, KanagaWa (JP) OTHER PUBLICATIONS
(73) Assigneer Fujitsu Limited, Kawasaki (JP) US. patent application Ser. No. 09/022,484, ShimiZu et al.,
_ _ _ _ _ ?led Feb. 12, 1998.
( * ) Notice: SubJect to any disclaimer, the term of this _ _ _ _
patent is extended or adjusted under 35 US. patent application Ser. No. 09/046,674, ShimiZu et al.,
U.S.C. 154(b) by 0 days. ?led Mar- 24> 1998
Jan Morovic, “To Develop a Universal Gamut Mapping
(21) App1_ N0; ()9/336,766 Algorithm” (Literature Survey), Design Research Center;
University of Derby, pp. 1—33, May 14, 1997.
(22) Filed: Jun. 21, 1999
(30) Foreign Application Priority Data (L15t Con?rmed on next page‘)
Oct. 26, 1998 (JP) ......................................... .. 10-304418 Primary Examiner_EdWard C0165
Assistant Examiner—Tia Carter
(51) Int. C1.7 .............................................. .. G06F 15/00 (74) Attorney) Agent) Or Firm_staas & Halsey LLP
(52) US. Cl. ...................... .. 358/1.9; 358/500; 358/518;
358/525; 382/162; 382/167 (57) ABSTRACT
(58) Field of Search ....................... .. 358/1.9, 500, 509, When an L*a*b* Value of a Certain Color is Outside a target
358/518’ 520’ 525; 382/166’ 167’ 162; color gamut to be converted, it isjudged Whether the L*a*b*
345/590’ 589’ 591’ 604 value is located Within the range of the color gamut set under
(56) References Cited a predetermined condition‘. This set range is a range in Which
the accuracy is degraded if colors are converted using only
US. PATENT DOCUMENTS a ?rst method, for example, a range in the neighborhood of
5,450,216 A * 9/1995 Kasson ..................... .. 358/518 the Color gamut‘ If a Color to be QOHVerted is located Within
5,583,666 A * 12/1996 Ellson et a1‘ 358518 the r*an*ge, colors are converted using a second method. If the
5,606,432 A * 2/1997 Ohtsuka et aL 358/527 L a b value of the color to be converted is outside of the
5,699,491 A * 12/1997 Barzel ___________ __ 395/109 set range, it is converted using the ?rst method until the
5,712,925 A * 1/1998 Ohga ,,,,,,,,, ,, 382/167 conversion result is contained Within the range. Then, the
5,724,442 A * 3/1998 Ogatsu et a1. 382/167 occurrence of both a problem Which the ?rst conversion
5,724,443 A * 3/1998 Nishikawa ------ - 382/167 method has for colors in the neighborhood of the color
57317818 A * 3/1998 Wan ct a1~ 345/590 gamut When colors are converted and a problem Which the
2 Z: 83:: """" " second method has in the conversion of a color far from the
5,933,253 A * 8/1999 110 618.1. 358/500 Color gamut can be Suppressed‘
6,104,829 A * 8/2000 Nakajima 382/167
6,130,675 A * 10/2000 Murai et a1. .............. .. 345/600 25 Claims, 19 Drawing Sheets
SECOND COLOR GAMUT J FIRST COLOR GAMUT
CONVERSION METHOD CONVERSION METHOD
1 1 86
s 4 /
OUTPUTS AN L * a" b * 3 mm COLOR GAMUT
VALUE AFTER coNvERsloN CONVERSION METHOD
1
OUTPUTS AN 1. * a * b *
VALUE AFTER CONVERSION
US 6,611,356 B1
Page 2
OTHER PUBLICATIONS R. S. Gentile et al., A Comparison of Techniques for Color
Garnut Misrnatch Cornpensation, Oct. 16, 1990, pp.
Jan Morovic, “To Develop a Universal Garnut Mapping
Algorithm” (literature Survey), Design Research Center, 176—181, Journal of Imaging Technology, Soc. for Imaging
University of Derby, pp. 1—33, May 14, 1997.* Science and Technology, Spring?eld, VA, US vol. 16, No. 5.
RS. Gentile et al. , A Comparison of Techniques for Color
J an Morovic et al., AUniversal Algorithm for Colour Garnut
Garnut Mismatch Cornpression, Oct. 16, 1990, pp. 176—181,
Journal of Imaging technology, Soc. for Imaging Science Mapping, Mar. 27, 1998, Colour Imaging in Multimedia
and Technology, Spring?eld, VA, US vol. 16, No. 5*.* Conference, Derby UK.
Jan Morovic et al., AUniversal Algorithm for Colour Garnut
European Patent Office, European Search Report, May 31,
Mapping, Mar. 27, 1998, Colour Imaging in Multimedia
Conference, derby UK.* 2002, pp. 1—3.
European Patent Of?ce, European search report, May 31,
2002, pp. 1—3.* * cited by eXarniner
U.S. Patent Aug. 26, 2003 Sheet 1 0f 19 US 6,611,356 B1
mmAm u
mmNJ
U.S. Patent Aug. 26, 2003 Sheet 2 0f 19 US 6,611,356 B1
EmZOEOJ_OmOmnUmm>.ZmO 0
ZWZOOE_JmLOmwQL>QZ?O 0
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U.S. Patent Aug. 26, 2003 Sheet 5 0f 19 US 6,611,356 B1
INPUTS AN L * a * b * VALUE OUTSIDE
COLOR GAMUT
WITHIN SET RANGE?
8 5
/
S 3
SECOND COLOR GAMUT FIRST COLOR GAMUT
CONVERSION METHOD CONVERSION METHOD
8 6
/
S 4
OUTPUTS AN |_* a* b * SECOND COLOR GAMUT
VALUE AFTER CONVERSION CONVERSION METHOD
S 7
Z
OUTPUTS AN |_*a* b*
VALUE AFTER CONVERSION
FIG. 5

U.S. Patent Aug. 26, 2003 Sheet 7 0f 19 US 6,611,356 B1
L=0, a=0, b=0 J 510
L255=LX16(PROVIDED. HOWEVER,L255=255 WHEN |_=1s),
L0=L255/2.55
a255=aX16(PROVIDED, HOWEVER, a255=255 WHEN a=16), J 81 1
a0=a255—128
b255=b><16(PROVlDED, HOWEVER, b255=255 WHEN b=I6),
b0=b255—128
s 1 2
CONVERTS USING Chord S 1 4
N0 CI inning
N0 COLOR (CONVERSION RESULT: L j
CONVERSION co' “0' “0)
I \l/
CALCULATES AMOUNT OF CONVERSION
C=sqrt(LO—Lc0)z+(a0—ac0)2+(b0—bc0)2)
S 1 6
S 1 7
J
S19L
CONVERTS T0 NEARES T
POINT
H520
CALCULATES A CMY VALUE CORRESPONDING T0
L‘a‘b‘ VALUE OBTAINED BY PROCESS
S21
REGISTERS AS
GEL] [a] [b] , MEL] [a] [b] . YEL] [a] [b]