Shape analysis method and shape analysis program

A shape analysis method for analyzing shape data acquired by measuring a contour shape of a workpiece to be measured, in a case of obtaining a peak point or a bottom point within an evaluation range, comprising:

• deciding one data point to be included in the evaluation range;
• calculating a differential coefficient at each point for an interval including the one data point;
• searching an interval sandwiched between inflection points while changing a width of the interval;
• pinpointing two boundary points between which the interval found by the search is sandwiched;
• obtaining two edge points at which the two boundary points are respectively shifted by preset shift amounts;
• setting a range sandwiched between the edge points in the evaluation range;
• and
• targeting the shape data within the evaluation range and calculating the peak point or the bottom point.

A recording medium for storing a shape analysis program for analyzing shape data acquired by measuring a contour shape of a workpiece to be measured, the shape analysis program causing a computer to execute the steps of:

• deciding a geometric element used in shape analysis;
• deciding one data point to be included in an evaluation range;
• applying the geometric element to an interval including the one data point;
• searching the widest interval for satisfying a threshold condition of a preset shape tolerance while changing a width of the interval;
• pinpointing two boundary points between which the interval found by the search is sandwiched;
• obtaining two edge points at which the two boundary points are respectively shifted by preset shift amounts;
• setting a range sandwiched between the edge points in the evaluation range;
• and
• targeting the shape data within the evaluation range for calculation of geometric properties.

A recording medium for storing a shape analysis program for analyzing shape data acquired by measuring a contour shape of a workpiece to be measured, in a case of obtaining a peak point or a bottom point within an evaluation range, the shape analysis program causing a computer to execute the steps of:

• deciding one data point to be included in the evaluation range;
• calculating a differential coefficient at each point for an interval including the one data point;
• searching an interval sandwiched between inflection points while changing a width of the interval;
• pinpointing two boundary points between which the interval found by the search is sandwiched;
• obtaining two edge points at which the two boundary points are respectively shifted by preset shift amounts;
• setting a range sandwiched between the edge points in the evaluation range;
• and
• targeting the shape data within the evaluation range and calculating the peak point or the bottom point.