Photonic Crystal - Size Measurement

Measure sizes of circular/triangular holes of photonic crystal structures

This MATLAB designer app is used to measure the diameter and period of periodic holes of photonic crystal structures.

• The image is binarized and filtered small objects (noise)
• If the air hole is circular, the function imfindcircles is used to detect circles. Center and radius are also calculated.
• If the air hole is triangular, the areas of objects are measured. Then, the effective length(l) is calculated based on the area (S), l = sqrt(4*S/sqrt(3)).
• The period is determined by measuring statistics of distances between two closet air holes on horizontal lines.

Note: The number of horizontal lines are calculated automatically using kmeans algorithm.

The reference is USAF 1951 Test Target.