Quantitative Error Metrics and Test Patterns for Enhanced Dielectric Resonator Imaging of Microwave Materials

A quantitative criterion based on structural similarity is proposed for the quality evaluation of permittivity images obtained by the recently proposed 2D SPDR scanning technique. The criterion is shown consistent with visual quality assessment, while opening way to rigorous optimization of parameters of post-processing methods for spatial resolution improvement below the SPDR head diameter. Two test images are also defined, providing a physical insight into the SPDR imaging method and facilitating its developments.