Emulation of X-ray Light-Field Cameras.

X-ray plenoptic cameras acquire multi-view X-ray transmission images in a single exposure (light-field). Their development is challenging: designs have appeared only recently, and they are still affected by important limitations. Concurrently, the lack of available real X-ray light-field data hinders dedicated algorithmic development.

3D Spatial Distribution of Nanoparticles in Mice Brain Metastases by X-ray Phase-Contrast Tomography.

Characterizing nanoparticles (NPs) distribution in multiple and complex metastases is of fundamental relevance for the development of radiological protocols based on NPs administration. In the literature, there have been advances in monitoring NPs in tissues. However, the lack of 3D information is still an issue.

EUV and Hard X-ray Hartmann Wavefront Sensing for Optical Metrology, Alignment and Phase Imaging.

For more than 15 years, Imagine Optic have developed Extreme Ultra Violet (EUV) and X-ray Hartmann wavefront sensors for metrology and imaging applications. These sensors are compatible with a wide range of X-ray sources: from synchrotrons, Free Electron Lasers, laser-driven betatron and plasma-based EUV lasers to High Harmonic Generation. In this paper, we first describe the principle of a Hartmann sensor and give some key parameters to design a high-performance sensor.

Simulation of Fresnel Zone Plate Imaging Performance with Number of Zones.

In recent years, integral imaging, a promising three-dimensional imaging technology, has attracted more and more attention for its broad applications in robotics, computational vision, and medical diagnostics. In the visible spectrum, an integral imaging system can be easily implemented by inserting a micro-lens array between a image formation optic and a pixelated detector. By using a micro-Fresnel Zone Plate (FZP) array instead of the refractive lens array, the integral imaging system can be applied in X-ray.

Modelling of Phase Contrast Imaging with X-ray Wavefront Sensor and Partial Coherence Beams.

The Hartmann wavefront sensor is able to measure, separately and in absolute, the real δ and imaginary part β of the X-ray refractive index. While combined with tomographic setup, the Hartman sensor opens many interesting opportunities behind the direct measurement of the material density. In order to handle the different ways of using an X-ray wavefront sensor in imaging, we developed a 3D wave propagation model based on Fresnel propagator.

High numerical aperture Hartmann wave front sensor for extreme ultraviolet spectral range.

We present a novel, to the best of our knowledge, Hartmann wave front sensor for extreme ultraviolet (EUV) spectral range with a numerical aperture (NA) of 0.15. The sensor has been calibrated using an EUV radiation source based on gas high harmonic generation.

Study of contrast variations with depth in focused plenoptic cameras.

A focused plenoptic camera has the ability to record and separate spatial and directional information of the incoming light. Combined with the appropriate algorithm, a 3D scene could be reconstructed from a single acquisition, over a depth range called plenoptic depth-of-field. In this Letter, we study the contrast variations with depth as a way to assess plenoptic depth-of-field.

Advanced light-field refocusing through tomographic modeling of the photographed scene.

Recently we have shown that light-field photography images can be interpreted as limited-angle cone-beam tomography acquisitions. Here, we use this property to develop a direct-space tomographic refocusing formulation that allows one to refocus both unfocused and focused light-field images. We express the reconstruction as a convex optimization problem, thus enabling the use of various regularization terms to help suppress artifacts, and a wide class of existing advanced tomographic algorithms.

Elemental and optical imaging evaluation of zwitterionic gold nanoclusters in glioblastoma mouse models.

We report in this study the in vivo biodistribution of ultra-small luminescent gold (Au) particles (∼1.5 nm core size; 17 kDa), so-called nanoclusters (NCs), stabilized by bidentate zwitterionic molecules in subcutaneous (s.c.

Tomographic approach for the quantitative scene reconstruction from light field images.

Current computational methods for light field photography model the ray-tracing geometry inside the plenoptic camera. This representation of the problem, and some common approximations, can lead to errors in the estimation of object sizes and positions. We propose a representation that leads to the correct reconstruction of object sizes and distances to the camera, by showing that light field images can be interpreted as limited angle cone-beam tomography acquisitions.

Ossicular motion related to middle ear transmission delay in gerbil.

The middle ear transmits sound efficiently from the air in the ear canal (EC) to the fluid filled cochlea. In gerbil, middle ear transmission produces a constant pressure gain between the EC and the cochlea of ∼25 dB from 2 to 40 kHz, and a delay-like phase corresponding to a ∼25-30 μs delay. The mechanisms by which the air-born signal is collected and delivered to the cochlea are not thoroughly understood, and the source of the delay is controversial.

A sum of simple and complex motions on the eardrum and manubrium in gerbil.

Based on comparisons of ear canal and scala vestibuli pressures the gerbil middle ear transmits sound with a gain of approximately 25 dB that is almost flat from 2 to 40 kHz, and with a delay-like phase corresponding to a 25-30 micros delay. How the middle ear is able to transmit sound with such high temporal and amplitude fidelity is not known, and is particularly mysterious given the complex motion the ossicles and tympanic membrane (TM) are known to undergo. To explore this question, we looked at the velocities of the manubrium and along a line on the TM.

The role of organ of Corti mass in passive cochlear tuning.

The mechanism for passive cochlear tuning remains unsettled. Early models considered the organ of Corti complex (OCC) as a succession of spring-mass resonators. Later, traveling wave models showed that passive tuning could arise through the interaction of cochlear fluid mass and OCC stiffness without local resonators.

Recording depth and signal competition in heterodyne interferometry.

A common way to measure submicroscopic motion of the organ of Corti is heterodyne interferometry. The depth over which vibration can be accurately measured with heterodyne interferometry is determined by both the optics, which controls to what extent light from nonfocal planes reaches the photodetectors, and demodulation electronics, which determines to what extent signal generated by out-of-focal-plane light influences the measurements. The influence of a second reflecting surface is investigated theoretically and experimentally.