US 7,397,972 B2Granted

Image transform method for obtaining expanded image data, image processing apparatus and image display device therefor

AssigneeInternational Business Machines Corporation

InventorsJunya Shimizu, Kazuo Sekiya

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Abstract

It is an object of the present invention to output a clear, expanded image wherein step-shapes or chain-shapes of oblique lines are reduced, distortion is eliminated and no constituent lines of fonts or graphics are missing. An image transform method, for transforming original input image data into image data expanded by a ratio represented by a rational number or an integer, comprises: a vertical and horizontal interpolation unit, for reducing correlation in the vertical and horizontal directions of interpolated image data linearly expanded from an original image data input unit, and for generating first expanded image data; an oblique interpolation unit, for performing linear interpolation, based on correlation with a target pixel constituting the original image data and neighboring pixels arranged in oblique directions, using the neighboring pixels to generate second expanded image data; and a final result generator for employing the first expanded image data and the second expanded image data to generate a final image.

Claims11

Dependent claims

An image transform method, for transforming original input image data into image data expanded by a ratio represented by a rational number or an integer, comprising the steps of:

reducing correlation in the vertical and horizontal directions of an image that is linearly expanded in the vertical and horizontal directions to generate first expanded image data by a rank order processing in a window having a predetermined size wherein a target pixel and its neighboring pixels in the linearly expanded image data are included;
performing linear interpolation, based on correlation with a target pixel constituting said original image data and neighboring pixels arranged in oblique directions, using said neighboring pixels to generate second expanded image data by determining an interpolation direction, wherein the neighboring pixels comprise a first neighboring pixel and a second neighboring pixel, and wherein determining an interpolation direction comprises:
calculating a left oblique difference using the target pixel and the first neighboring pixel;
calculating a right oblique difference using the target pixel and the second neighboring pixel;
determining the left oblique direction to be the interpolation direction when the left oblique difference is smaller than a threshold value and when the right oblique difference is greater than a threshold value;
and
determining the right oblique direction to be the interpolation direction when the left oblique difference is greater than a threshold value and when the right oblique difference is smaller than a threshold value;
and
employing said first expanded image data and said second expanded image data in an arithmetic combination to generate a final image.

6 more elements

An image processing apparatus comprising:

input means for entering original image data to be expanded;
vertical and horizontal directional interpolation means for interpolating said original image data in the vertical and horizontal directions;
vertical and horizontal directional correlation reduction means for reducing correlation of the obtained image in the vertical and horizontal directions;
oblique direction detection means for detecting an oblique direction having a strong correlation with a target pixel and neighboring pixels in said original image data, wherein the neighboring pixels comprise a first neighboring pixel and a second neighboring pixel, and wherein detecting an oblique direction comprises:
calculating a left oblique difference using the target pixel and the first neighboring pixel;
calculating a right oblique difference using the target pixel and the second neighboring pixel;
detecting the left oblique direction to be the oblique direction when the left oblique difference is smaller than a threshold value and when the right oblique difference is greater than a threshold value;
and
detecting the right oblique direction to be the oblique direction when the left oblique difference is greater than a threshold value and when the right oblique difference is smaller than a threshold value;
and
directional interpolation means for employing said neighboring pixels in said detected oblique direction to perform interpolation in said oblique direction.

8 more elements

An image processing apparatus for transforming original input image data into expanded image data comprising:

an interpolation direction determination unit for reading a target pixel and neighboring pixels in original image data, and for determining an interpolation direction, wherein the neighboring pixels comprise a first neighboring pixel and a second neighboring pixel, and wherein determining an interpolation direction comprises:
calculating a left oblique difference using the target pixel and the first neighboring pixel;
calculating a right oblique difference using the target pixel and the second neighboring pixel;
detecting the left oblique direction to be the interpolation direction when the left oblique difference is smaller than a threshold value and when the right oblique difference is greater than a threshold value;
and
detecting the right oblique direction to be the interpolation direction when the left oblique difference is greater than a threshold value and when the right oblique difference is smaller than a threshold value;
and
an oblique directional linear interpolation unit for performing linear interpolation for said target pixel by using said neighboring pixels arranged in said determined interpolation direction.

5 more elements

Dependencies are inferred from the claim text.