Point spread function based image reconstruction in optical projection tomography

As a result of the shallow depth of focus of the optical imaging system, the use of standard filtered back projection in optical projection tomography causes space-variant tangential blurring that increases with the distance to the rotation axis. We present a novel optical tomographic image reconstruction technique that incorporates the point...

New method for probe position correction for Ptychography

For high resolution imaging, X-rays and electron beams are being used. However, for such a short wavelength, imaging with lenses becomes difficult as lenses absorb a part of radiation and lenses with very low aberrations must be used. Ptychography is a lens-less imaging technique which uses intensity information of the multiple diffraction...

Workshop on reconstruction schemes for magnetic resonance data: Summary of findings and recommendations

The high-fidelity reconstruction of compressed and lowresolution magnetic resonance (MR) data is essential for simultaneously improving patient care, accuracy in diagnosis and quality in clinical research. Sponsored by the Royal Society through the Newton Mobility Grant Scheme, we held a halfday workshop on reconstruction schemes for MR data...

Image Reconstuction in MRI: The Possibilities of Portable Low-cost MRI Scanners

Hydrocephalus is one of the most common abnormalities affecting the nervous system of children around the globe. Especially in developing countries hydrocephalus is a large problem. It is often left untreated resulting in suffering, brain damage, developmental delays and ultimately death. This makes an early detection more opportune than ever....

Optimizing modelling in iterative image reconstruction for preclinical pinhole PET

The recently developed versatile emission computed tomography (VECTor) technology enables high-energy SPECT and simultaneous SPECT and PET of small animals at sub-mm resolutions. VECTor uses dedicated clustered pinhole collimators mounted in a scanner with three stationary large-area NaI(Tl) gamma detectors. Here, we develop and validate...

Comparing different ultrasound imaging methods for breast cancer detection

Ultrasound is frequently used to evaluate suspicious masses in breasts. These evaluations could be improved by taking advantage of advanced imaging algorithms, which become feasible for low frequencies if accurate knowledge about the phase and amplitude of the wave field illuminating the volume of interest is available. In this study, we compare...

Gas Jets in Granular Matter: Observed by a High Speed X-ray Tomography System

High speed X-ray tomography is a promising tool to visualize the time-resolved gas distribution for fluidized beds. The tomography unit at Delft University of Technology is composed of three X-ray tubes and three double-layer detector arrays. The X-ray tubes are places at 120? around the fluidized bed. The detector arrays are placed opposite to...

Image acquisition and reconstruction in multi-pinhole emission tomography

Nowadays, tomographic imaging techniques are inseparable from modern medical practice as they allow non-invasive 3-dimensional visualization of the interior of a patient in order to e.g. establish a medical diagnosis, or to monitor disease progression and the effects of disease treatment. Next to clinical use, tomographic imaging techniques are...

Effect of temperature and fixation on the optical properties of atherosclerotic tissue: A validation study of an ex-vivo whole heart cadaveric model

Atherosclerotic plaque composition can be imaged using the optical attenuation coefficient derived from intravascular optical coherence tomography (OCT) data. The relation between optical properties and tissue type has been established on autopsy tissues. In this study, we validate an ex-vivo model for the effect of temperature and tissue...

Joint optimization of phase diversity and adaptive optics: Demonstration of potential

We study different possibilities to use adaptive optics (AO) and phase diversity (PD) together in a jointly optimized system. The potential of the joint system is demonstrated through numerical simulations. We find that the most significant benefits are obtained from the improved deconvolution of AO-corrected wavefronts and the additional...

Image processing of optical coherence tomography for image guided dental drilling

In the past two decades, dental implants have been an essential component of the public health. However, lack of a reliable and safe dental surgery imaging modality remains a major problem. Optical coherence tomography (OCT) is an interferometic optical imaging modality that is somewhat similar to B-mode ultrasound but utilizes infrared light...

3D near-infrared imaging based on a single-photon avalanche diode array sensor

An imager for optical tomography was designed based on a detector with 128x128 single-photon pixels that included a bank of 32 time-to-digital converters. Due to the high spatial resolution and the possibility of performing time resolved measurements, a new contact-less setup has been conceived in which scanning of the object is not necessary....

Towards an algebraic multigrid method for tomographic image reconstruction -- improving convergence of ART

In this paper we introduce a multigrid method for sparse, possibly rank-deficient and inconsistent least squares problems arising in the context of tomographic image reconstruction. The key idea is to construct a suitable AMG method using the Kaczmarz algorithm as smoother. We first present some theoretical results about the correction step and...

Dynamic MR-Imaging with Radial Scanning, a Post-Acquisition Keyhole Approach

A new method for 2D/3D dynamic MR-Imaging with radial scanning is proposed. It exploits the inherent strong oversampling in the centre of k-space, which holds crucial temporal information of the contrast evolution. It is based on (1) a rearrangement of (novel 3D) isotropic distributions of trajectories during the scan according to the desired...

Measuring & modeling of concentrated settling suspensions using electrical impedance tomography

Image reconstruction from biplane angiographic projections, Beeldreconstructie vanuit tweevlaks angiografische projecties

CADISS: a multi-processor system for image compression/decompression on board scientific satellites

Project CADISS has produced an elegant breadboard of a system for compression (and -if required- decompression) of signals generated by imaging sensors on-board scientific satellites. The performance, specifications and physical characteristics of CADISS are the result of trade-offs on function (algorithms), technology, through-put speed and...