Claims
- 1. A color image processing apparatus for performing undercolor removal, comprising:
- inputting means for inputting a color image signal;
- first generating means for generating a grayness signal from the color image signal;
- second generating means for generating a darkness signal from the color image signal;
- undercolor removal means for performing undercolor removal based on the grayness signal, the darkness signal, and a black signal corresponding to the color image signal; and
- control means for controlling an amount of undercolor removal performed on the color image signal so that a gradient of an amount of undercolor removal performed on the color image signal relative to the grayness signal at a first darkness signal level is lower than a gradient of an amount of undercolor removal performed on the color image signal relative to the grayness signal at a second darkness signal level, wherein the second darkness signal level is lower than the first darkness signal level.
- 2. The apparatus according to claim 1, wherein the black signal, which is varied based upon Y (yellow), M (magenta) and C (cyan) signals of the color image signal is adopted as an input signal of masking processing.
- 3. The apparatus according to claim 2, wherein the undercolor removal means performs undercolor removal based upon the Y, M and C signals and the amount of undercolor removal controlled by the control means.
- 4. The apparatus according to claim 1, wherein the grayness signal becomes larger as the color image signal approaches achromaticity, and the darkness signal becomes larger as a density of the color image signal increases.
- 5. A color image processing method for performing undercolor removal, comprising the steps of:
- inputting a color image signal;
- generating a grayness signal from the color image signal;
- generating a darkness signal from the color image signal;
- performing undercolor removal based on the grayness signal, the darkness signal, and a black signal corresponding to the color image signal; and
- controlling an amount of undercolor removal performed on the color image signal so that a gradient of an amount of undercolor removal performed on the color image signal relative to the grayness signal at a first darkness signal level is lower than a gradient of an amount of undercolor removal performed on the color image signal relative to the grayness signal at a second darkness signal level, wherein the second darkness signal level is lower than the first darkness signal level.
- 6. The method according to claim 5, wherein the black signal, which is varied based upon Y (yellow), M (magenta) and C (cyan) signals of the color image signal is adopted as an input signal of masking processing.
- 7. The method according to claim 6, wherein the undercolor removal is performed based upon the Y, M and C signals and the amount of undercolor removal controlled in the controlling step.
- 8. The method according to claim 5, wherein the grayness signal becomes larger as the color image signal approaches achromaticity, and the darkness signal becomes larger as a density of the color image signal increases.
Priority Claims (2)
Number |
Date |
Country |
Kind |
4-226856 |
Aug 1992 |
JPX |
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5-001685 |
Jan 1993 |
JPX |
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Parent Case Info
This application is a division of application Ser. No. 08/550,520, filed Oct. 30, 1995, now U.S. Pat. No. 5,673,335, which is a continuation of application Ser. No. 08/111,403, filed Aug. 25, 1993, now abandoned.
US Referenced Citations (17)
Foreign Referenced Citations (3)
Number |
Date |
Country |
56-135842 |
Oct 1981 |
JPX |
56-140350 |
Nov 1981 |
JPX |
63-183459 |
Jul 1988 |
JPX |
Non-Patent Literature Citations (1)
Entry |
Shimizu, Toshihiro, Undercolor Removal Method and Device, PTO 98-2718 (translation), Japanese Kokai Patent Application No. Sho 56[1981]-135842, 1981, pp. 1-19. |
Divisions (1)
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Number |
Date |
Country |
Parent |
550520 |
Oct 1995 |
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Continuations (1)
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Number |
Date |
Country |
Parent |
111403 |
Aug 1993 |
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