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作者： Kline, Timothy Lee University of Minnesota

学位级别：Ph.D.

Microvascular branching geometries determine the efficacy of the transport of nutrients and metabolic products to and from tissues in large-bodied organisms. The general 'plan' is that an artery supplies oxygen, nutrients, and hormones to the tissue and a vein removes metabolic products from that tissue. The blood flow to the organ is controlled by the metabolic demand of the organ by a feedback mechanism controlling the arterial lumen diameter. The liver differs from other organs by having two vascular systems delivering its blood - the hepatic artery and the portal vein. The hepatic artery supplies the oxygen needed by liver cells, and the portal vein delivers the molecules absorbed by the gut which need to be processed by the liver tissue for use by other organs in the body. However, how the hepatic artery and portal vein interact is not fully understood in terms of how their relative flows are adjusted, either passively and/or actively, to meet the needs of the liver tissue. This dissertation explores the hypothesis that the hepatic artery's blood mixes with the portal vein's proximal to the hepatic sinusoids (where their mixing is traditionally thought to occur). This is performed utilizing micro-CT to image rat liver lobes injected with a contrast polymer. During the process of exploring this hypothesis, a number of image analysis tools needed to be developed. For one, understanding the level of accuracy by which geometrical measurements can be made by micro-CT is very important because vascular resistance to flow is proportional to the interbranch segment length, as well as inversely proportional to the fourth power of the lumen diameter. Moreover, a single vessel tree contained in a micro-CT image has hundreds, if not thousands of individual interbranch segments and knowledge of the interconnectivity relationship between the segments is important for modeling such properties as pressure distributions and relative blood flow rates. For these reasons, the deve

关键词： algorithm development Anatomy Centerline extraction Modulation transfer function Segmentation Small animal

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Low Cost MATLAB-Based Pulse Oximeter for Deployment in Research and development Applications

Low Cost MATLAB-Based Pulse Oximeter for Deployment in Resea...

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Annual International Conference of the IEEE Engineering in Medicine and Biology Society

作者： M. Shokouhian R. C. S. Morling I. Kale Applied DSP and VLSI Research Group Electronics Network and Computer Engineering Department

ISBN: (纸本)9781457702150

Problems such as motion artifact and effects of ambient lights have forced developers to design different signal processing techniques and algorithms to increase the reliability and accuracy of the conventional pulse oximeter device. To evaluate the robustness of these techniques, they are applied either to recorded data or are implemented on chip to be applied to real-time data. Recorded data is the most common method of evaluating however it is not as reliable as real-time measurements. On the other hand, hardware implementation can be both expensive and time consuming. This paper presents a low cost MATLAB-based pulse oximeter that can be used for rapid evaluation of newly developed signal processing techniques and algorithms. Flexibility to apply different signal processing techniques, providing both processed and unprocessed data along with low implementation cost are the important features of this design which makes it ideal for research and development purposes, as well as commercial, hospital and healthcare application.

关键词： Pulse oximeter Pc-based algorithm development MATLAB

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Proton radiography in three dimensions: A proof of principle of a new technique

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MEDICAL PHYSICS 2013年第10期40卷 101917-101917页

作者： Raytchev, Milen Seco, Joao Harvard Univ Sch Med Dept Radiat Oncol Boston MA 02114 USA Massachusetts Gen Hosp Boston MA 02114 USA

Purpose: Monte Carlo simulations were used to investigate a range of phantom configurations to establish enabling three-dimensional proton radiographic techniques. Methods: A large parameter space of stacked phantom geometries composed of tissue inhomogeneity materials such as lung, bone, and cartilage inserted within water background were simulated using a purposefully modified version of TOPAS, an application running on top of the GEANT4 Monte Carlo code. The phantoms were grouped in two classes, one with the inhomogeneity inserted only half-way in the lateral direction and another with complete inhomogeneity insertion. The former class was used to calculate the track count and the energy fluence of the protons as they exit the phantoms either having traversed the inhomogeneity or not. The latter class was used to calculate one yield value accounting for loss of protons due to physical processes only and another yield value accounting for deliberately discarded protons due to large scattering angles. A graphical fingerprinting method was developed to determine the inhomogeneity thickness and location within the phantom based on track count and energy fluence information. Two additional yield values extended this method to the general case which also determines the inhomogeneity material and the phantom thickness. Results: The graphical fingerprinting method was manually validated for two, and automatically tested for all, tissue materials using an exhaustive set of inhomogeneity geometries for 16 cm thick phantoms. Unique recognition of test phantom configurations was achieved in the large majority of cases. The method in the general case was further tested using an exhaustive set of inhomogeneity and phantom tissues and geometries where the phantom thicknesses ranged between 8 and 24 cm. Unique recognition of the test phantom configurations was achieved only for part of the phantom parameter space. The correlations between the remaining false positive recognition

关键词： 3D proton radiography proton radiography algorithm development 3D computed radiography Monte Carlo

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development OF A NOVEL algorithm TO CALCULATE THE OPTIC PROPERTIES OF TEMPORAL AEROSOLS THROUGH REMOTE SENSING DATA MEASUREMENTS: PROSPECTIVE STUDY

DEVELOPMENT OF A NOVEL ALGORITHM TO CALCULATE THE OPTIC PROP...

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IEEE International Geoscience and Remote Sensing Symposium

作者： Gloria Elena Faus-Landeros Ivan E. Villalon-Turrubiates Edward A. Celarier Dianne Q. Robinson ITESM Campus Guadalajara Zapopan Jalisco ITESO Universidad Jesuita de Guadalajara NASA Goddard Space Flight Center Hampton University

ISBN: (纸本)9781467311601

Satellite' sensors as well as ground-based sun photometers instruments surface are utilized gather data about the quantitative composition of components in the Earth's atmosphere. The relationships among these components produce effects in different phenomena, like regional climate change. Aerosols, consisting of particles from 0.01 to 10 μm, are atmosphere components, whose effects are still poorly understood. Through Remote Sensing, it is possible to classify them and gain information about their role in different atmospheric processes: low visibility, solar energy balance, cloud formation and increases or decreases of the quantity of precipitation. This paper describes how the study and analysis of satellite-based and ground-based measurements can be used to develop and validate a novel procedure to calculate the optical properties of temporal aerosols found in and around Guadalajara, based on previous algorithms:, to determine the aerosol size distribution function, scattering phase function, single scattering albedo, complex refractive index and asymmetry parameter. The quantifiable knowledge about the temporal and regional aerosols' optical properties will contribute to future investigations related to their quantitative effects on atmospheric processes in this region. These effects include: alteration of weather and climate, change of the tropospheric temperature, contribution to environmental ills, the formation and properties of the clouds, effects on the ecosystems, local solar energy balance, and the impacts on human health.

关键词： Photometry Remote Sensing Aerosols Aerosol's optical properties NASA satellite data inter comparison algorithm development

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Advances in landslide nowcasting: evaluation of a global and regional modeling approach

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ENVIRONMENTAL EARTH SCIENCES 2012年第6期66卷 1683-1696页

作者： Kirschbaum, Dalia Bach Adler, Robert Hong, Yang Kumar, Sujay Peters-Lidard, Christa Lerner-Lam, Arthur NASA Hydrol Sci Branch Goddard Space Flight Ctr Greenbelt MD 20771 USA Univ Maryland ESSIC College Pk MD 20740 USA Univ Oklahoma Sch Civil Engn & Environm Sci Norman OK 73072 USA Univ Oklahoma Natl Weather Ctr ARRC Atmospher Radar Res Ctr Norman OK 73072 USA Sci Applicat Int Corp SAIC Beltsville MD USA Columbia Univ Lamont Doherty Earth Observ Palisades NY 10964 USA

The increasing availability of remotely sensed data offers a new opportunity to address landslide hazard assessment at larger spatial scales. A prototype global satellite-based landslide hazard algorithm has been developed to identify areas that may experience landslide activity. This system combines a calculation of static landslide susceptibility with satellite-derived rainfall estimates and uses a threshold approach to generate a set of 'nowcasts' that classify potentially hazardous areas. A recent evaluation of this algorithm framework found that while this tool represents an important first step in larger-scale near real-time landslide hazard assessment efforts, it requires several modifications before it can be fully realized as an operational tool. This study draws upon a prior work's recommendations to develop a new approach for considering landslide susceptibility and hazard at the regional scale. This case study calculates a regional susceptibility map using remotely sensed and in situ information and a database of landslides triggered by Hurricane Mitch in 1998 over four countries in Central America. The susceptibility map is evaluated with a regional rainfall intensity-duration triggering threshold and results are compared with the global algorithm framework for the same event. Evaluation of this regional system suggests that this empirically based approach provides one plausible way to approach some of the data and resolution issues identified in the global assessment. The presented methodology is straightforward to implement, improves upon the global approach, and allows for results to be transferable between regions. The results also highlight several remaining challenges, including the empirical nature of the algorithm framework and adequate information for algorithm validation. Conclusions suggest that integrating additional triggering factors such as soil moisture may help to improve algorithm performance accuracy. The regional algorithm scenario r

关键词： Landslide forecasting Hazard inventory algorithm development Central America Hurricane Mitch

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Practical image registration concerns overcome by the weighted and filtered mutual information metric

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JOURNAL OF ELECTRONIC IMAGING 2012年第2期21卷 023029-1-023029-17页

作者： Keane, Tommy P. Saber, Eli Rhody, Harvey Savakis, Andreas Raj, Jeffrey Rochester Inst Technol Chester F Carlson Ctr Imaging Sci Rochester NY 14623 USA Rochester Inst Technol Dept Elect & Microelect Engn Rochester NY 14623 USA Rochester Inst Technol Dept Comp Engn Rochester NY 14623 USA Lenel Syst Int Inc Pittsford NY 14534 USA

Contemporary research in automated panorama creation utilizes camera calibration or extensive knowledge of camera locations and relations to each other to achieve successful results. Research in image registration attempts to restrict these same camera parameters or apply complex point-matching schemes to overcome the complications found in real-world scenarios. This paper presents a novel automated panorama creation algorithm by developing an affine transformation search based on maximized mutual information (MMI) for region-based registration. Standard MMI techniques have been limited to applications with airborne/satellite imagery or medical images. We show that a novel MMI algorithm can approximate an accurate registration between views of realistic scenes of varying depth distortion. The proposed algorithm has been developed using stationary, color, surveillance video data for a scenario with no a priori camera-to-camera parameters. This algorithm is robust for strict-and nearly-affine-related scenes, while providing a useful approximation for the overlap regions in scenes related by a projective homography or a more complex transformation, allowing for a set of efficient and accurate initial conditions for pixel-based registration. (C) 2012 SPIE and IS&T. [DOI: 10.1117/***.21.2.023029]

关键词： Principal component analysis Wavelets Databases Facial recognition systems Detection and tracking algorithms Feature extraction Image registration algorithm development Autoregressive models Cameras

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Special section guest editorial: Quality control by artificial vision

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Journal of Electronic Imaging 2012年第2期21卷

作者： Pinoli, Jean-Charles Panetta, Karen Hata, Seiji LPMG Laboratory Ecole Nationale Supérieure des Mines UMR CNRS 5148 158 Cours Fauriel 42023 Saint-Etienne Cedex 2 France Tufts University Department of Electrical and Computer Engineering 161 College Avenue Medford MA 02155 United States Kagawa University Faculty of Engineering 1-1 Saiwai-cho Takamatsu 760-8526 Japan

Abstract unavailable.

关键词： Machine vision Analytical research Image analysis Image processing algorithm development Computer engineering Computing systems Control systems Mathematical modeling Mining

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How Dangerous Is Looking Away From the Road? algorithms Predict Crash Risk From Glance Patterns in Naturalistic Driving

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HUMAN FACTORS 2012年第6期54卷 1104-1116页

作者： Liang, Yulan Lee, John D. Yekhshatyan, Lora Liberty Mutual Res Inst Safety Hopkinton MA 01748 USA Univ Wisconsin Dept Ind & Syst Engn Madison WI 53706 USA Univ Iowa Iowa City IA USA

Objective: In this study, the authors used algorithms to estimate driver distraction and predict crash and near-crash risk on the basis of driver glance behavior using the data set of the 100-Car Naturalistic Driving Study. Background: Driver distraction has been a leading cause of motor vehicle crashes, but the relationship between distractions and crash risk lacks detailed quantification. Method: The authors compared 24 algorithms that varied according to how they incorporated three potential contributors to distraction-glance duration, glance history, and glance location-on how well the algorithms predicted crash risk. Results: Distraction estimated from driver eye-glance patterns was positively associated with crash risk. The algorithms incorporating ongoing off-road glance duration predicted crash risk better than did the algorithms incorporating glance history. Augmenting glance duration with other elements of glance behavior-1.5th power of duration and duration weighted by glance location-produced similar prediction performance as glance duration alone. Conclusions: The distraction level estimated by the algorithms that include current glance duration provides the most sensitive indicator of crash risk. Application: The results inform the design of algorithms to monitor driver state that support realtime distraction mitigation systems.

关键词： distraction estimation algorithm development driver distraction eye-glance patterns

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Face Recognition from a Moving Platform via Sparse Representation

Face Recognition from a Moving Platform via Sparse Represent...

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Conference on Independent Component Analyses, Compressive Sampling, Wavelets, Neural Net, Biosystems, and Nanoengineering X

作者： Hsu, Ming Kai Hsu, Charles Lee, Ting N. Szu, Harold George Washington Univ ECE Dept Washington DC 20052 USA

ISBN: (纸本)9780819490797

A video-based surveillance system for passengers includes face detection, face tracking and face recognition. In general, the final recognition result of the video-based surveillance system is usually determined by the cumulative recognition results. Under this strategy, the correctness of face tracking plays an important role for the system recognition rate. For face tracking, the challenges of face tracking on a moving platform are that the space and time information used for conventional face tracking algorithms may be lost. Consequently, conventional face tracking algorithms can barely handle the face tracking on a moving platform. In this paper, we have verified the state-of-the-art technologies for face detection, face tracking and face recognition on a moving platform. In the mean time, we also proposed a new strategy for face tracking on a moving platform or face tracking under very low frame rate. The steps of the new strategy for face detection are: (1) classification the detected faces over a certain period instead of every frame (2) Tracking of each passenger is equivalent to reconstruct the time order of certain period for each passenger. If the cumulative recognition results are the only part needed for the surveillance system, step 2 can be skipped. In addition, if the additional information from the passengers is required, such as path tracking, lip read, gesture recognition, etc, time order reconstruction in step 2 can offer the information required.

关键词： Facial recognition systems Video Video surveillance Detection and tracking algorithms Surveillance systems Sensors algorithm development Machine vision Surveillance Reconstruction algorithms

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A System for Saccular Intracranial Aneurysm Analysis and Virtual Stent Planning

A System for Saccular Intracranial Aneurysm Analysis and Vir...

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Conference on Medical Imaging - Image-Guided Procedures, Robotic Interventions and Modeling

作者： Baloch, Sajjad Sudarsky, Sandra Zhu, Ying Mohamed, Ashraf Geiger, Bernhard Dutta, Komal Namburu, Durga Nias, Puthenveettil Martucci, Gary Redel, Thomas Siemens Corp Res Princeton NJ 08540 USA Siemens Hoffman Estates IL 60192 USA Siemens AG Munich Germany

ISBN: (纸本)9780819489654

Recent studies have found correlation between the risk of rupture of saccular aneurysms and their morphological characteristics, such as volume, surface area, neck length, among others. For reliably exploiting these parameters in endovascular treatment planning, it is crucial that they are accurately quantified. In this paper, we present a novel framework to assist physicians in accurately assessing saccular aneurysms and efficiently planning for endovascular intervention. The approach consists of automatically segmenting the pathological vessel, followed by the construction of its surface representation. The aneurysm is then separated from the vessel surface through a graph-cut based algorithm that is driven by local geometry as well as strong prior information. The corresponding healthy vessel is subsequently reconstructed and measurements representing the patient-specific geometric parameters of pathological vessel are computed. To better support clinical decisions on stenting and device type selection, the placement of virtual stent is eventually carried out in conformity with the shape of the diseased vessel using the patient-specific measurements. We have implemented the proposed methodology as a fully functional system, and extensively tested it with phantom and real datasets.

关键词： Neck Image segmentation 3D image reconstruction Reconstruction algorithms Transform theory algorithm development Digital imaging Europium Feature extraction Virtual reality

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