We report on a novel nondestructive and reversible method for coupling free space light to planar optical waveguides. In this method, an elastomeric grating is used to produce an effective refractive index modulation on the surface of the optical waveguide. The external elastomeric grating binds to the surface of the waveguide with van der Waals forces and makes conformal contact without any ap...

We conduct an exhaustive survey of image thresholding methods, categorize them, express their formulas under a uniform notation, and finally carry their performance comparison. The thresholding methods are categorized according to the information they are exploiting, such as histogram shape, measurement space clustering, entropy, object attributes, spatial correlation, and local gray-level surf...

Over the past decade, efforts have been made to develop nondestructive techniques for three-dimensional (3D) grain-orientation mapping in crystalline materials. 3D x-ray diffraction microscopy and differential-aperture x-ray microscopy can now be used to generate 3D orientation maps with a spatial resolution of 200 nanometers (nm). We describe here a nondestructive technique that enables 3D ori...

Microwave nondestructive testing methods become nowadays ever more exploited electromagnetic evaluation method not only dielectric but also metal materials surface and volume homogeneity. A novel microwave sensor created from open waveguide with metamaterial structure for non-destructive testing was developed in an attempt to increase the sensitivity of the microwave nondestructive evaluation m...

The properties of advanced composites rely on the quality of the fiber-matrix bonding. Service-induced damage results in deterioration of bonding quality, seriously compromising the load-bearing capacity of the structure. While traditional methods to assess bonding are destructive, herein a nondestructive methodology based on shear wave reflection is numerically investigated. Reflection relies ...

Structural Health Monitoring (SHM) is a systematic method for nondestructive evaluation of a structure’s performance by sensing, extracting and analyzing features of the structural system. Most approaches for damage recognition in SHM focus on statistical analyses. We introduce a method to improve nondestructive evaluation for damage assessment by performing damage diagnosis using fuzzy sets. W...

Nondestructive testing (NDT) of historic structures can be used for architectural archaeology, structural stability analysis, or materials characterization. Four types of physical probes are available: sound, penetrating radiation, visible light, and electromagnetism. Each of these can be utilized in several ways. Additional options involve hybrid techniques that combine probe methods. Widespre...

Radiation damage is considered to be the major problem that still prevents imaging an individual biological molecule for structural analysis. So far, all known mapping techniques using sufficient short wavelength radiation, be it x rays or high energy electrons, circumvent this problem by averaging over many molecules. Averaging, however, leaves conformational details uncovered. Even the antici...