Using Optical Coherence Tomography to Reveal the Hidden History of The Landsdowne Virgin of the Yarnwinder by Leonardo da Vinci and Studio.

Optical coherence tomography (OCT) was used for non-invasive examination of a well-known, yet complex, painting from the studio of Leonardo da Vinci in combination with routine imaging in various bands of electromagnetic radiation. In contrast with these techniques, OCT provides depth-resolved information. Three post-processing modalities were explored: cross-sectional views, maps of scattering from given depths, and their 3D models.

Application of 3D digital image correlation to track displacements and strains of canvas paintings exposed to relative humidity changes.

This paper introduces a methodology for tracking displacements in canvas paintings exposed to relative humidity changes. Displacements are measured by means of the 3D digital image correlation method that is followed by a postprocessing of displacement data, which allows the separation of local displacements from global displacement maps. The applicability of this methodology is tested on measurements of a model painting on canvas with introduced defects causing local inhomogeneity.

Depth-resolved multilayer pigment identification in paintings: combined use of laser-induced breakdown spectroscopy (LIBS) and optical coherence tomography (OCT).

A detailed feasibility study on the combined use of laser-induced breakdown spectroscopy with optical coherence tomography (LIBS/OCT), aiming at a realistic depth-resolved elemental analysis of multilayer stratigraphies in paintings, is presented. Merging a high spectral resolution LIBS system with a high spatial resolution spectral OCT instrument significantly enhances the quality and accuracy of stratigraphic analysis. First, OCT mapping is employed prior to LIBS analysis in order to assist the selection of specific areas of interest on the painting surface to be examined in detail.

Four-dimensional structural and Doppler optical coherence tomography imaging on graphics processing units.

The authors present the application of graphics processing unit (GPU) programming for real-time three-dimensional (3-D) Fourier domain optical coherence tomography (FdOCT) imaging with implementation of flow visualization algorithms. One of the limitations of FdOCT is data processing time, which is generally longer than data acquisition time. Utilizing additional algorithms, such as Doppler analysis, further increases computation time.

Structural examination of easel paintings with optical coherence tomography.

Identification of the order, thickness, composition, and possibly the origin of the paint layers forming the structure of a painting, that is, its stratigraphy, is important in confirming its attribution and history as well as planning conservation treatments. The most common method of examination is analysis of a sample collected from the art object, both visually with a microscope and instrumentally through a variety of sophisticated, modern analytical tools. Because of its invasiveness, however, sampling is less than ideally compatible with conservation ethics; it is severely restricted with respect to the amount of material extirpated from the artwork.

Characterization of Laser Cleaning of Artworks.

The main tasks of conservators of artworks and monuments are the estimation and analysis of damages (present condition), object conservation (cleaning process), and the protection of an object against further degradation. One of the physical methods that is becoming more and more popular for dirt removal is the laser cleaning method. This method is non-contact, selective, local, controlled, self-limiting, gives immediate feedback and preserves even the gentlest of relief - the trace of a paintbrush.

Spectral optical coherence tomography: a novel technique for cornea imaging.

Purpose: Spectral optical coherence tomography (SOCT) is a new, noninvasive, noncontact, high-resolution technique that provides cross-sectional images of the objects that weakly absorb and scatter light. SOCT, because of very short acquisition time and high sensitivity, is capable of providing tomograms of substantially better quality than the conventional OCT. The aim of this paper is to show the application of the SOCT to cross-sectional imaging of the cornea and its pathologies.

Spectral optical coherence tomography: a new imaging technique in contact lens practice.

Purpose: Spectral optical coherence tomography (SOCT) is a new non-invasive, non-contact, high-resolution technique, which provides cross-sectional images of objects that weakly absorb and scatter light. The aim of this article is to demonstrate the application of SOCT to imaging of eyes fitted with contact lenses.

Methods: Nine eyes of six different subjects fitted with various contact lenses have been examined with a slit-lamp and a prototype SOCT instrument.

Ophthalmic imaging by spectral optical coherence tomography.

Purpose: To demonstrate two novel ophthalmic imaging techniques based on fast Spectral Optical Coherence Tomography (SOCT).

Design: Prospective observation case report.

Setting: Research laboratory.

Fluorescence polarization studies of B-phycoerythrin oriented in polymer film.

Polarized steady-state fluorescence and fluorescence excitation spectra as well as time-resolved fluorescence for B-phycoerythrin (B-PE) from red algae, Porphyridium cruentum, embedded in polyvinyl stretched films were measured. The lifetimes of polarized fluorescence were analyzed using exponential components and fractal models. The interactions between various chromophores of the pigment-protein complexes investigated were discussed.

Real-time in vivo imaging by high-speed spectral optical coherence tomography.

An improved spectral optical coherence tomography technique is used to obtain cross-sectional ophthalmic images at an exposure time of 64 micros per A-scan. This method allows real-time images as well as static tomograms to be recorded in vivo.