Data generation method and data generation apparatus

A data generation apparatus for selecting one of the tread surface and the side wall surface of a tire as a surface to be measured and generating shape data used to evaluate a bulge/dent and a runout formed on the surface to be measured, comprising:

• a shape sensor;
• a height data acquiring unit configured to scan the surface to be measured using the shape sensor at a predetermined sampling period and acquire height data items for one line;
• a candidate extraction unit configured to provide a candidate extraction process to retrieve, from among the height data items for one line, a given number of consecutive height data items starting from a given sample point, calculate a difference between the median of the retrieved height data items and each of the retrieved height data items, and extract, as candidates of a singular point, the sample points each having the difference that is greater than or equal to a height threshold value and perform the candidate extraction process for the entire region of the height data items for one line while shifting the starting point;
• and
• an interpolation unit configured to select, from among the candidates of a singular point, the candidates of a singular point that satisfy predetermined conditions as singular points, remove the selected singular points from the height data items, interpolate the height data items at the removed singular points using the height data items at the sample points that are neighbors of the singular point and that are not singular points, and generate the shape data,
• wherein the height threshold value is a predetermined value that is greater than or equal to the product of the largest slope of the bulge/dent calculated from pre-generated model data representing the shape of the bulge/dent and half a width corresponding to the given number.