Method for fitting third-degree Bezier curves to series of data points

摘要

In curve fitting with respect to a series of data points representing a figure, control points Q1, Q2 are set for a parameter tx in accordance with a start point Q0, an end point Q3, and a passing point X, and gradients ϑ0, ϑ3, ϑx of the respective points. A gradient ϑ(tx) of a Bezier curve specified on the basis of the start and end points Q0, Q3 and the control points Q1, Q2 is obtained for the parameter tx. If the gradient ϑ(tx), the gradient ϑx and a predeter­mined reference gradient ϑref satisfy a relation of |ϑ(tx)-ϑx| ϑref, the curve specified by the start and end points Q0, Q3 and the control points Q1, Q2 for the parameter tx is determined to be a Bezier curve passing the passing point X.