| 摘要 |
PROBLEM TO BE SOLVED: To compress gradation digital picture data before compression with a high compression rate by a triangular plane patch. SOLUTION: The gradation digital picture data where two-dimensional position coordinates in the directions of X and Y axes and a luminance value in the direction of Z axis can be recognized by each pixel are compressed by developing the data into a three-dimensional space consisting of the X, Y and Z axes to generate the three-dimensional luminance curved surface 400 which is quadrilateral in the directions of the X and Y axes, drawing a single diagonal line 500 over the curved surface 400 to generate two triangular three-dimensional luminance planes 510 and 520 and approximating the curved surface 400 based on the X, Y and Z coordinates of the three vertexes of the respective planes 510 and 520 to compress the gradation digital picture data. |
