An image processing device capable of processing images containing poorly contrasted letters and/or bold letters in addition to well contrasted letters and pictures such that both resolutions of letters and tones of pictures can be preserved. The device may includes a circuit to distinguish two level images from non two level images according to image concentration related quantity, and a circuit to distinguish picture images out of non two level images according to another image concentration related quantity. The device may include a circuit to distinguish letters from pictures according to the maximum and the minimum values of the image concentration related quantity. The device may includes a circuit to distinguish letters from pictures according to the maximum and the minimum values of changes in the image concentration related quantity. The device may include a circuit to distinguish letters from pictures according to the square sum average of differences in the image concentration related quantity between neighboring picture elements.
申请公布号
US5001767(A)
申请公布日期
1991.03.19
申请号
US19880277605
申请日期
1988.11.29
申请人
KABUSHIKI KAISHA TOSHIBA
发明人
YONEDA, HITOSHI;MACHIDA, HIRONOBU;KANNO, HIROKI;IZAWA, KOJI