Method for combining height maps and profilometer for the same

A non-transitory computer readable medium including software which, when run on a processor of a profilometer including a sensor which has pixels for measuring a first height map and a second height map of the sample surface of a sample, causes the profilometer to perform a method for measuring a first height map and a second height map of a sample surface of a sample with a profilometer and combining the first and second height maps to a composite height map, the method including:

• combining the first and second height maps to a composite height map, the method including:
• measuring the first and second height maps with a sensor of the profilometer, wherein the sensor is moved relative to the sample surface so that the first and second height maps are measured in partially overlapping fields of view of the sensor;
• combining the first and second height maps to produce the composite height map of the sample surface,
• wherein the combining of the first and second height maps includes:
• determining a first overlap region of the first and second height maps by partially overlapping the first and second height maps, in which first overlap region the first and second height maps overlap;
• determining a first similarity between the first and second height maps by determining a similarity between the heights of the first and second height maps in the first overlap region using a similarity measure;
• determining a second overlap region of the first and second height maps by shifting the first and second height maps relative to each other compared to the first overlap region;
• determining a second similarity between the first and second height maps by determining a similarity between the heights of the first and second height map in the second overlap region using the similarity measure;
• comparing the first and second similarities by normalizing the first and second similarities based on the respective surface areas of the overlap regions;
• and
• combining the first and second height maps by stitching the first and second height maps in one of the overlap regions based on the comparing of the first and second similarity measures.