Ultra-high resolution Fourier domain optical coherence tomography for resolving thin layers in painted works of art

While OCT has been applied to the non-invasive examination of the stratigraphy of paint layers in recent years, it has been recognized that the resolutions of commercially available OCT cannot compete in depth resolution with conventional microscopic examination of cross-sections of paint samples. It is necessary to achieve resolutions better than 3 microns to resolve the thinnest layers of paint and varnish. In this paper, we demonstrate a Fourier domain ultrahigh resolution OCT at 810nm with depth resolution of 1.8μm in air (or 1.2μm in varnish or paint)

A novel 2D filter design methodology

Published versio

Knowledge representation on design of storm drainage system

Innovations in applied artificial intelligence : 17th International Conference on Industrial and Engineering Applications of Artificial Intelligence and Expert Systems, IEA/AIE 2004, Ottawa, Canada, May 17-20, 2004Author name used in this publication: Kwokwing Chau2003-2004 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Long wavelength optical coherence tomography for painted objects

Optical Coherence Tomography has been successfully applied to the imaging of painted objects in recent years. However, a significant limitation is the low penetration depth of OCT in paint because of the high opacity of paint due to either scattering or absorption. It has been shown that the optimum spectral window for OCT imaging of paint layers is around 2.2μm in wavelength. In this paper, we demonstrate a 1950nm OCT for imaging painted objects using a superfluorescent fiber source at low power

High resolution fourier domain optical coherence tomography at 2 microns for painted objects

Optical Coherence Tomography has been successfully applied to the non-invasive imaging of subsurface microstructure of a variety of materials from biological tissues to painted objects of art. One of the limitations of the technique is the low depth of penetration due to the strong scattering and absorption in the material. Previous studies found that for paint materials, the optimum window for large depth of penetration is around 2.2 microns. This is also true for many other materials with low water content. We have previously demonstrated OCT systems in this wavelength regime for imaging with improved depth of penetration. In this paper, we present an improved 2 micron high resolution Fourier domain OCT system using a broadband supercontinuum source. The system achieved a depth resolution of 9 microns in air (or 6 microns in paint or any polymer)

A novel 2D filter design methodology for heterogeneous devices

Published versio

Perceived oral health condition and self-satisfaction with oral health

published_or_final_versio

Chloramphenicol succinate a competitive substrate and inhibitor of succinate dehydrogenase: relation to its mechanisms of toxicity

published_or_final_versio

Severe digital ischaemia treated with phosphodiesterase inhibitors

published_or_final_versio

High resolution Fourier domain optical coherence tomography in the 2 μm wavelength range using a broadband supercontinuum source

A 220 nm bandwidth supercontinuum source in the two-micron wavelength range has been developed for use in a Fourier domain optical coherence tomography (FDOCT) system. This long wavelength source serves to enhance probing depth in highly scattering material with low water content. We present results confirming improved penetration depth in high opacity paint samples while achieving the high axial resolution needed to resolve individual paint layers. This is the first FDOCT developed in the 2 μm wavelength regime that allows fast, efficient capturing of 3D image cubes at a high axial resolution of 13 μm in air (or 9 μm in paint)