A major source of artifacts in diffusion-weighted imaging is subject motion. Slow bulk subject motion causes misalignment of data when more than one average or diffusion gradient direction is acquired. Fast bulk subject motion can cause signal dropout artifacts in diffusion-weighted images and results in erroneous derived maps, e.g., fractional anisotropy maps. To address both types of artifact...

In this chapter we introduce our task: communicating a digital message without error (or with as few errors as possible) despite an imperfect communications medium. Figure 1.1 shows a typical communications system. In this text we will assume that our source is producing binary data, but it could equally be an analog source followed by analog-to-digital conversion. Through the early 1940s, engi...

This paper describes how geometric distortion correction and image processing operation can be performed in realtime on an IVIP system. The IVIP is a modified version of RVIP RVIP is currently being manufactured and it is going to be used for radar signal processing. The IVP is targeted to perform the time consuming first stages of image processing. This includes geometric distortion correction...

Spatio-temporal pattern formation in contra-directional two-wave mixing in photorefractive crystals is investigated both numerically and analytically, taking high-modulation-depth effects into account. We use a modified two-wavemixing model that includes a correction function f ðmÞ, which is introduced as a phenomenological modification. Transverse instabilities arise only if the modulation dep...

In this paper, a beamforming correction for identifying dipole sources by means of phased microphone array measurements is presented and implemented numerically and experimentally. Conventional beamforming techniques, which are developed for monopole sources, can lead to significant errors when applied to reconstruct dipole sources. A previous correction technique to microphone signals is exten...

INTRODUCTION Artifacts caused by motion during the image acquisition are a well known problem at 1.5T and 3T. In high field systems such as 7T the available signal to noise ratio leads to potentially higher resolution than in systems with lower field. Unfortunately higher resolution requires longer acquisition times without patient motion. Therefore an increased need for motion correction exist...

PURPOSE Analyze the characteristics of TLD LiF-100 powder between multiple LiF crystal batches. METHODS The RPC used TLD LiF-100 encapsulated powder to verify the output for photon and electron beams for 4 to 23 MV X-ray beams and 6 to 23 MeV electron beams, respectively, from the past 15 years. During that time period, the RPC commissioned more than 15 batches of TLD powder. Commissioning of...

This discussion paper is/has been under review for the journal Earth System Dynamics (ESD). Please refer to the corresponding final paper in ESD if available. Abstract Statistical bias correction is commonly applied within climate impact modeling to correct climate model data for systematic deviations of the simulated historical data from observations. Methods are based on transfer functions ge...

We present a method for the numerical correction of optical aberrations based on indirect sensing of the scattered wavefront from point-like scatterers ("guide stars") within a three-dimensional broadband interferometric tomogram. This method enables the correction of high-order monochromatic and chromatic aberrations utilizing guide stars that are revealed after numerical compensation of defoc...

Numerical simulations of atmospheric turbulence and adaptive optics (AO) wavefront correction are performed to investigate the time scale for fringe motion in optical interferometers with spatial filters. These simulations focus especially on partial AO correction, where only a finite number of Zernike modes are compensated. The fringe motion is found to depend strongly on both the aperture dia...