Measurement method and measurement program

A non-transitory computer-readable recording medium that stores a measurement program for measuring a surface state of an object having a curved shape by measuring a distance from a measurement head to the object, when executed by a computer causes the computer to:

• set a measuring region of the object and a threshold value of concave and convex;
• acquire shape reference data including the curved shape of the object;
• acquire three-dimensional data of the surface of the object by measuring the distance between the object in the measuring region and the measurement head;
• acquire curve removed data by removing the shape reference data from the three-dimensional data;
• calculate a second reference data by calculating first reference data based on the curve removed data, by removing data exceeding the threshold value with respect to the first reference data, from the curve removed data, and by averaging the curve removed data from which the data exceeding the threshold value is removed;
• and
• calculate shape data of the concave and convex by extracting data exceeding the threshold value with respect to the second reference data, from the curve removed data.