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

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.

1 - 4 . (canceled) 
     
     
         5 . 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:
 forming an image by linearly expanding original image data in the vertical and horizontal directions; and   reducing the vertical and horizontal directional correlation of said image through a rank order processing to generate a final expanded image, wherein the rank order processing includes:   raster-scanning a window enclosing a target pixel and one or more of its neighboring pixels; and   computing an output value of the target pixel by performing an averaging operation on pixels enclosed within the window.   
     
     
         6 . The image transform method according to  claim 5 , further comprising the steps of:
 determining, for said expanded image, whether the contrast in said original image data can be maintained at a predetermined level; and   extracting a high frequency component from said expanded image, when said contrast can not be maintained at said predetermined level, and adding said frequency component multiplied by a constant to said expanded image, or subtracting said frequency component multiplied by a constant from said expanded image.   
     
     
         7 - 14 . (canceled) 
     
     
         15 . An image processing apparatus for transforming original input image data into expanded image data comprising:
 a vertical and horizontal directional linear interpolation unit for forming an image by linearly expanding original image data in the vertical and horizontal directions; and   a vertical and horizontal directional correlation reduction processing unit for reducing, for said image, a vertical and horizontal directional correlation using a rank order processing to generate a final expanded image, operating in combination for transforming the original input image data into expanded image data, wherein the rank order processing includes:
 raster-scanning a window enclosing a target pixel and one or more of its neighboring pixels; and 
 computing an output value of the target pixel by performing an averaging operation on pixels enclosed within the window. 
   
     
     
         16 . 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;   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   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, operating in combination for transforming the original input image data into expanded image data.   
     
     
         17 . The image processing apparatus according to  claim 16 , wherein said interpolation direction determination unit reads peripheral pixels arranged within a predetermined mask range adjacent to said target pixel and/or said neighbor pixels and adds together the differences between said peripheral pixels and said target pixel and said neighbor pixels, and determines said interpolation direction based on the cumulative value of said differences. 
     
     
         18 - 20 . (canceled) 
     
     
         21 . An article of manufacture comprising a computer usable medium having computer readable program code means embodied therein for causing image transformation, the computer readable program code means in said article of manufacture comprising computer readable program code means for causing a computer to effect the steps of  claim 5 . 
     
     
         22 - 24 . (canceled) 
     
     
         25 . A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for image transformation, said method steps comprising the steps of  claim 5 . 
     
     
         26 - 28 . (canceled) 
     
     
         29 . A computer program product comprising a computer usable medium having computer readable program code means embedded therein for causing image processing, the computer readable program code means in said computer program product comprising computer readable program code means for causing a computer to effect the steps of  claim 15 . 
     
     
         30 . A computer program product comprising a computer usable medium having computer readable program code means embedded therein for causing image processing, the computer readable program code means in said computer program product comprising computer readable program code means for causing a computer to effect the steps of  claim 16 . 
     
     
         31 . (canceled)