METHOD AND DEVICE FOR COMPRESSING SHAPE DATA AND METHOD AND DEVICE FOR EXPANDING SHAPE DATA

摘要

PROBLEM TO BE SOLVED: To provide a method and device for compressing shape data by which the shape data of such a living being as the human being, animals, etc., and such an artificial object as the automobile, airplane, etc., having various curved surfaces can be compressed effectively. SOLUTION: The sequences of points of three-dimensional coordinates or two-dimensional coordinates indicating the shape of an object are converted into sequences of points in a one-dimensional normal space (processes 1 to 4) and the one-dimensional normal space is divided into partial spaces (small sections) (process 5). Then the distribution of the converted sequences of points in each section is checked (process 6) and the dividing width of each section is appropriately changed (process 8). Thereafter, the average value of the coordinate values of the sequences of points in each section when the dividing width is a decided one is coded (processes 9 and 10) and each converted sequence of points is converted into a code based on the coded average value (process 11).