SHAPE PARAMETER CALCULATING METHOD AND DEVICE FOR EXECUTING THE SAME

PROBLEM TO BE SOLVED: To provide a shape parameter calculating method for accurately calculating the shape parameters of a primitive by a conventional and simple calculation, using a measuring point on the outer surface of a shape. SOLUTION: By setting the number of shape parameters for describing the shape of a primitive to be larger than an irreducibly minimum number and describing the shape and the evaluation function of the primitive by using a vector formula, the shape and the evaluation function of the primitive at an optional position and optional inclination can be expressed simply. Then, by using an analytical method for obtaining the minimum solution of the evaluation function by the method of least squares, restriction on the position of a measuring point is eliminated and influence due to a specific measuring point having a large error can be suppressed. Thus, it is possible to provide the calculating method of the shape parameters of the primitive which is for general-purpose and high in calculation accuracy.