Surface anomaly detecting device, system, method, and non-transitory computer-readable medium

A method comprising:

• dividing a structure into a plurality of clusters based on position information of a plurality of points on a surface of the structure;
• creating a cluster group by coupling together two or more of the clusters;
• determining a reflection luminance normal value of the cluster group based on a distribution of reflection luminance values at a plurality of points on a surface of the cluster group;
• and
• identifying an anomalous portion on the surface of the cluster group based on a difference between the reflection luminance normal value and the reflection luminance value at each of the plurality of points on the surface of the cluster group.

A program that causes a computer to execute:

• dividing a structure into a plurality of clusters based on position information of a plurality of points on a surface of the structure;
• creating a cluster group by coupling together two or more of the clusters;
• determining a reflection luminance normal value of the cluster group based on a distribution of reflection luminance values at a plurality of points on a surface of the cluster group;
• and
• identifying an anomalous portion on the surface of the cluster group based on a difference between the reflection luminance normal value and the reflection luminance value at each of the plurality of points on the surface of the cluster group.