发明名称 Image processing apparatus and method for reproducing high quality image in low-density portion
摘要 When an image is adjusted to compensate for individual differences among image forming units, there are cases where a phenomenon occurs in which a contour that is originally non-existent appears in a low-density portion, namely an area other than that where the output density characteristic is linear. In such instances image quality deteriorates markedly when importance is placed upon tonality. To solve this problem, a printer is caused to print an image diagnostic pattern, the image diagnostic pattern that has been printed is read by a reader and the linear portion of the output density characteristic of a design center value and the linear portion of the read output density characteristic are approximated by straight lines. Both of the output density characteristics are compared and image adjustment coefficients A, B are compared. The coefficients A, B thus obtained are set in a primary converter and gamma tables in a gamma converter are changed over in conformity with the values of the coefficients A, B.
申请公布号 US6226108(B1) 申请公布日期 2001.05.01
申请号 US19960745935 申请日期 1996.11.08
申请人 CANON KABUSHIKI KAISHA 发明人 TOYOHARA YUICHIRO;KUNISHI TSUYOSHI;WATANABE YUKIO
分类号 G06T5/00;H04N1/407;(IPC1-7):G03F3/08;H04N1/46 主分类号 G06T5/00
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