Determining a dimension of a regular pattern of elements

A method for determining a dimension of a regular pattern of elements, wherein the elements in the regular pattern are arranged along an arrangement direction in accordance with a first spatial frequency, the method comprising:

• providing a sensor for sampling the regular pattern;
• operating the sensor to provide a first plurality of data samples while sampling over a portion of the regular pattern;
• providing a plurality of data sample sets, wherein each data sample set consists of a different number of data samples and each data sample set comprises data samples selected from the first plurality of data samples;
• analyzing each of the data sample sets in a frequency domain to determine a corresponding spatial frequency value representative of the first spatial frequency;
• determining a plurality of quantified values, wherein each quantified values is associated with one of the spatial frequency values;
• selecting a first quantified value from the plurality of quantified values;
• and
• determining the dimension based at least on the spatial frequency value associated with the selected first quantified value.