The diffraction tomography theorem is adapted to one-dimensional length measurement. The resulting spectral interferometry technique is described and the first length measurements using this technique on a model eye and on a human eye in vivo are presented.

Measurement of intraocular distances by backscattering spectral interferometry

Improved fracture toughness and integrated damage sensing capability by spray coated CNTs on carbon fibre prepreg Part A Applied science and manufacturing

This paper presents a fully-automated algorithm to segment fluid-associated (fluid-filled) and cyst regions in optical coherence tomography (OCT) retina images of subjects with diabetic macular edema (DME).

/pdf/fully-automated-segmentation-of-fluid-cyst-regions-in-1f93nw173j.pdf

Fully-Automated Segmentation of Fluid/Cyst Regions in Optical Coherence Tomography Images with Diabetic Macular Edema using Neutrosophic Sets and Graph Algorithms

The application of fiber-reinforced polymer (FRP) composites is continuously increasing due to their superior mechanical properties and the associated weight advantage. However, they are susceptible to more complex types of damage, and advanced damage characterization systems are required to prevent catastrophic failures. Various non-destructive testing and evaluation (NDT&E) and in-situ structural health monitoring (SHM) techniques have been applied for damage detection in FRP composites. These techniques have been continuously developed to achieve reliable inspections, especially for safety-critical applications such as the aerospace industry. This review presents recent advances in NDT&E techniques and SHM techniques, particularly for damage diagnosis in FRP composites. For selecting the most suitable NDT technique based on specific criteria, the analytical hierarchy process is applied as a decision-making tool to evaluate and rank the NDT techniques. The size of the specimen is found to be the most important criterion that significantly affects technique selection. Finally, the importance of developing in-situ SHM systems is outlined, and different in-situ SHM systems are then reviewed and discussed. This review provides progress of the recent damage characterization techniques and enables researchers to devise selection criteria to select the most appropriate technique for their own work.

Advancements in fiber-reinforced polymer composite materials damage detection methods: Towards achieving energy-efficient SHM systems

Inspection of concrete structures externally reinforced with FRP composites using active infrared thermography: A review

Advances, limitations and prospects of nondestructive testing and evaluation of thick composites and sandwich structures: A state-of-the-art review

Critical insights into the state-of-the-art NDE data fusion techniques for the inspection of structural systems

We proposed a high-performance optical coherence velocimeter (OCV) based on broadband optical interference which achieves spatial resolution from interference cancellation or enhancement of different components of the broadband light. There is a challengeable issue for OCV that the interference fringes become blurred when the velocity of detected object is relatively large, hindering the pace of OCV application in high-velocity field. To resolve this, the relationship between blurry coefficient and OCV system parameters (e.g., exposure time, central wavelength, bandwidth of source) was derived. It was found that blurry coefficient changed with oscillatory decay form and reached the minimum at each order blurry velocity. It showed that maximum measurable velocity of OCV systems could reach 10th order blurry velocity. The measurement of vibration of the loudspeaker driven by a function signal generator was employed to experimentally verify the velocity measurement performance of the system. The experiment demonstrated that the developed OCV can provide large velocity measurement ranges from static to 25.2 mm/s with nanometer-level precision and maximum measurable vibration frequency of up to 50 kHz. However, in theory, the theoretical maximum measurable velocity can be up to 1.06 m/s for current OCV configuration. The OCV has high precision, large dynamic range, and high-velocity measurement capability, making it attractive for applications in mechanical structure vibration monitoring and acoustic measurement.

High-performance optical coherence velocimeter: theory and applications.

Full-range Fourier-domain optical coherence tomography based on Mach–Zehnder interferometer

An acoustic-excitation optical coherence vibrometer (AE-OCV) is proposed for noncontact microstructure vibration measurement and modal analysis. The vibration dynamic parameters of the microstructure can be captured with a subnanometer displacement resolution by the proposed AE-OCV using spectral wavelength calibration algorithm and spectral center correction method. The natural frequency of the microstructure could also be obtained by the developed noncontact AE-OCV system using the swept-frequency acoustic excitation method. Furthermore, a home-made spectrometer based on a high-speed linear camera could provide the system with a frequency measurement range of 0–50 kHz. The developed AE-OCV has an excellent performance in microstructures vibration measurement and modal analysis, especially for high-frequency and nanoscale vibration measurements. It is of great significance to the design of the microelectromechanical system (MEMS), such as the noncontact dynamic measurement of cantilevered beams in atomic force microscopy.

Jiewen Lin

Papers

Advances, limitations and prospects of nondestructive testing and evaluation of thick composites and sandwich structures: A state-of-the-art review

Critical insights into the state-of-the-art NDE data fusion techniques for the inspection of structural systems

High-performance optical coherence velocimeter: theory and applications.

Full-range Fourier-domain optical coherence tomography based on Mach–Zehnder interferometer

Acoustic-Excitation Optical Coherence Vibrometer for Real-Time Microstructure Vibration Measurement and Modal Analysis