Method and apparatus for expanding image data

A method for expanding original image data, in which a plurality of pixels is arranged in a matrix, so as to obtain expanded-image data partitioned into a plurality of blocks, each of which is composed of a plurality of pixels, said method comprising:

• a first step that sets a magnifying power regarding at least one of a first direction along a width and a second direction along a length in said original image data;
• a second step that arranges each pixel in said original image data at a position corresponding to a center position of each of said plurality of blocks in accordance with said magnifying power;
• a third step that inspects whether said magnifying power is odd numbered;
• a fourth step that shifts pixel generating positions relative to each corresponding pixel of said original image data by a shifting-amount corresponding to said magnifying power such that each arranged pixel of said original image data is off-center with respect to said plurality of blocks, when said magnifying power is the odd numbered;
• and
• a fifth step that generates said expanded-image data corresponding to said magnifying power by applying a fluency transform to each pixel in said original image data, each pixel in said original image data being subjected to said fluency transform at one of the position corresponding to said center position of each block and an off-center position with respect to each block.

A memory medium that stores a program for expanding original image data comprising:

• a first step that sets a magnifying power regarding at least one of a direction along a width and a direction along length in said original image data;
• a second step that arranges each pixel in said original image data at a position corresponding to a center position of each of said plurality of blocks in accordance with said magnifying power;
• a third step that inspects whether said magnifying power is odd numbered;
• a fourth step that shifts pixel generating positions relative to each corresponding pixel of said original image data by a shifting-amount corresponding to said magnifying power, such that each arranged pixel of said original image data is off-center with respect to said plurality of blocks, when said magnifying power is the odd numbered;
• and
• a fifth step that generates said expanded-image data corresponding to said magnifying power by applying a fluency transform to each pixel in said original image data, each pixel in said original image data being subjected to said fluency transform at one of the position corresponding to said center position of each block and an off-center position with respect to each block.