Dainippon Screen Mfg. Co., Ltd.

Souichi Kimura

Shigeaki Shimazu

Tetsuo Asano

Interpolation of gradation levels of an image without degradation of the quality of the image is disclosed. The image is searched in the vertical direction from an objective pixel (Pt) to be subjected to the gradation level interpolation for a high-level pixel (Pvh) located closest to the objective pixel (Pt), and then searched in the horizontal direction from the objective pixel (Pt) for a high-level pixel (Phh) located closest to the objective pixel (Pt). A comparison is made between the high-level pixels (Pvh, Phh) to determine the distance from the objective pixel (Pt) to one of the high-level pixels which is closer to the objective pixel (Pt) as a high-level distance (D ). Similar operation is performed to extract low-level pixels (Pvl, Phl), and a comparison is made therebetween to determine a low-level distance (D ). The gradation level of the objective pixel (Pt) is determined based on the high-level distance (D ) and low-level distance (D ).

Method of and apparatus for interpolating gradation levels of image

A mask area is specified as a target area of modification in a multi-tone image. The multi-tone image is converted to a plurality of binary images with a plurality of threshold values. A plurality of density-contours corresponding to the plurality of binary images are extracted. Without implementing any contraction or expansion, a portion overlapping the contour of the mask area is deleted from each extracted density-contour. A plurality of modified density-contours which do not include the portions overlapping the contour of the mask area are converted back to a modified multi-tone image.

Method and apparatus for modifying multi-tone image

The multi-tone image data is converted to a plural sets of binary image data with a plurality of density levels as threshold values. Contraction and expansion are sequentially executed on the plural sets of binary image data to correct a contour of each binary image. The plural sets of the processed binary image data are re-converted to multi-tone image data which represents a multi-tone image having a corrected contour.

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Kyoto, Japan

Souichi Kimura