Discrete Cosine Transform Technique for Measuring Domain Widths in Magneto-Optic Garnet Films

One use of engineered magneto-optic garnet thin films is to visualize magnetic patterns with high spatial resolution. Of these engineered films, films with out-of-plane anisotropy exhibiting a stripe domain pattern are found to work well for resolving patterns in digital storage magnetic media. The width of the stripe domains in garnet films has become a performance metric for the films' ability to visualize high spatial-frequency magnetic patterns. Current manual image-based methods for measuring stripe domain width are tedious, complicated, and susceptible to bias and human error. In this paper, an improved measurement method with repeatable precision utilizing the discrete cosine transform is presented and compared with the manual measurement of the same sample image. The measurements were in agreement.