Hardwood Log Breakdown Decision Automation

This paper examines the use of internal log defect information, such as can be obtained from noninvasive defect detection imaging, e.g., computed tomography, magnetic resonance, etc., in the automation of log breakdown decisions for hardwood logs. A method was developed to extract the information and convert it into a form that can directly drive the saw equipment controllers to perform the log breakdown. This method illustrates the feasibility of hardwood log breakdown decision automation

Cork structural characteristics and their influence on the oxygen ingress through wine stoppers

Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia - ULCork structural characteristics and their influence on the oxygen ingress through wine stoppers were studied aiming to contribute to an increased added-value of the natural cork stoppers. The surface porosity features of cork stoppers can differentiate the three main commercial classes used nowadays: the porosity coefficient was 2.4%, 4.0% and 5.5% for premium, good and standard stoppers, respectively. Image analysis also distinguished defects in the cork structure: empty ant gallery; Coroebus undatus F. larvae gallery; and wetcork. Several predictive classification models of stoppers into quality classes were built using the results from cork stoppers surface characterization and a simplified model using the main discriminant features i.e. porosity coefficient and the RGB colour-type variables was presented. X-ray tomography was used as a non-destructive technique to study the internal structure of natural cork stoppers, allowing the visualization of some defects inside the cork stopper. After characterization, the natural cork stoppers were used as closure of bottles and oxygen diffusion measurements were made along time. The kinetics of oxygen transfer was similar and could be adjusted to logarithmic models. On average 35% of the overall oxygen ingress occurred in the first 5 days, 59% in the 1st month and 78% in the first 3 months. Microtomography images (voxel size of 50 µm) allowed the observation of lenticular channels development and geometry, and the quantification of void and high density regions (HDR) fractions. The evidence that the void fraction of lenticular channels in the innermost part of the cork stopper inserted in the bottle was strongly related to the oxygen ingress in the first month after bottling can be used for quality enhancement of natural cork stoppers with incorporation of performance requirement

Development of correction algorithm for pulsed terahertz computed tomography (THz-CT)

For last couple of decades, there has been a considerable improvement in Terahertz (THz) science, technology, and imaging. In particular, the technique of 3-D computed tomography has been adapted to the THz range. However, it has been widely recognized that a fundamental limitation to THz computed tomography imaging is the refractive effects of the sample under study. The finite refractive index of materials in the THz range can severally refract THz beams which probe the internal structure of a sample during the acquisition of tomography data. Refractive effects lead to anomalously high local absorption coefficients in the reconstructed image near the material’s boundaries. Three refractive effects are identified: (a) Fresnel reflection power losses at the boundaries, (b) an increase in path length of the probing THz radiation, and (c) steering of the THz beam by the sample such that the emerging THz radiation is no longer collected by the THz detector. In addition, the finite size of the THz beam dominates the measured THz transmission when the edges of the sample are probed using THz tomography. These boundary phenomena can dominate in the reconstructed THz-CT images making it difficult to distinguish any hidden finer structural defect(s) inside the material. In this dissertation, an algorithm has been developed to remove these refractive and finite beam size effects from THz-CT reconstructed images. The algorithm is successfully implemented on cylindrical shaped objects. A longer term goal of the research is to study the internal structure of natural cork wine stoppers by pulsed Terahertz tomography (THz-CT). It has previously been shown that THz imaging can detect the internal structure of natural cork. Moreover, the internal structure of natural cork stoppers dominates the diffusion of gasses and liquids through the cork. By using THz computed tomography, one can recreate a 3D image of the sample’s internal structure which could then be used to predict non-destructively the diffusion properties of the cork. However, refractive and boundary effects which arise in the THz tomographic image masks the presence of the cork’s internal structure. Applying the correction algorithms which are developed in this dissertation to natural cork stoppers suppresses the refractive and boundary anomalies enabling better visualization of the cork’s internal structure

Computer Integrated Manufacturing Issues Related to the Hardwood Log Sawmill

This paper evaluates the issues associated with the computer integration of the various technologies now available to hardwood log sawmills, so that these technologies will cooperate in helping the sawmill achieve better lumber yield. The concept of computer integration, and the current sawmill setup, are reviewed. A model of a computer-integrated hardwood sawmill is described. Issues concerning the integration of both hardware and software are also discussed

Tools for creating wide-field views of the human retina using Optical Coherence Tomography

Optical Coherence Tomography (OCT) has allowed in-vivo viewing of details of retinal layers like never before. With the development of spectral domain OCT (SD-OCT) details of nearly 2µm axial resolution and higher imaging speed have been reported. Nevertheless, a single volume scan of the retina is typically restricted to 6mm x 6mm in size. Having a larger field of view of the retina will definitely enhance the clinical utility of the OCT. A tool was developed for creating wide-field thickness maps of the retina by combining the use of already available tools like i2k Retina (DualAlign, LLC, Clifton Park, NY) and the thickness maps from Cirrus HD-OCT research browser (Carl Zeiss Meditec, Dublin, California, USA). Normal subjects (n=20) were imaged on Zeiss Cirrus HD-OCT using 512x128 Macular Cube scanning protocol. Sixteen overlapping volumetric images were obtained by moving the internal fixation target around such that the final stitched maps were 12mm x 14mm in size. The thickness maps were corrected for inter-individual differences in axial lengths measured using Zeiss IOL Master and averaged to obtain a normative map. An algorithm was also developed for montaging 3-D volume scans. Using this algorithm two OCT volume scans can be registered and stitched together to obtain a larger volume scan. The algorithm can be described as a two step process involving 3-D phase-correlation and 2-D Pseudo-polar Fourier transform (PPFT). In the first step, 3-D phase-correlation provides translation values in the x, y and z axis. The second step involves applying PPFT on each overlapping pair of B-scans to find rotation in the x-y plane. Subsequent volumes can be stitched to obtain a large field of view. We developed a simple and robust method for creating wide-field views of the retina using existing SD-OCT hardware. As segmentation algorithms improve, this method could be expanded to produce wide-field maps of retinal sub-layers, such as the outer nuclear layer or retinal nerve fiber layer. These wide-field views of the retina may prove useful in evaluating retinal diseases involving the peripheral retina (e.g., retinitis pigmentosa and glaucoma)

ToScA North America (6 – 8 June 2017, The University of Texas, Austin, TX) Program

ToScA North America will address key areas of science, including Multi-modal Imaging, Geosciences, Forensics, Increasing Contrast, Educational Outreach, Data, Materials Science and Medical and Biological Science.University of Texas High-Resolution X-ray CT Facility (UTCT); Jackson School of Geosciences, The University of Texas at Austin; Natural History Museum (London); Royal Microscopical Society (Oxford, UK)Geological Science

Echocardiography

The book "Echocardiography - New Techniques" brings worldwide contributions from highly acclaimed clinical and imaging science investigators, and representatives from academic medical centers. Each chapter is designed and written to be accessible to those with a basic knowledge of echocardiography. Additionally, the chapters are meant to be stimulating and educational to the experts and investigators in the field of echocardiography. This book is aimed primarily at cardiology fellows on their basic echocardiography rotation, fellows in general internal medicine, radiology and emergency medicine, and experts in the arena of echocardiography. Over the last few decades, the rate of technological advancements has developed dramatically, resulting in new techniques and improved echocardiographic imaging. The authors of this book focused on presenting the most advanced techniques useful in today's research and in daily clinical practice. These advanced techniques are utilized in the detection of different cardiac pathologies in patients, in contributing to their clinical decision, as well as follow-up and outcome predictions. In addition to the advanced techniques covered, this book expounds upon several special pathologies with respect to the functions of echocardiography

Sub-pixel Registration In Computational Imaging And Applications To Enhancement Of Maxillofacial Ct Data

In computational imaging, data acquired by sampling the same scene or object at different times or from different orientations result in images in different coordinate systems. Registration is a crucial step in order to be able to compare, integrate and fuse the data obtained from different measurements. Tomography is the method of imaging a single plane or slice of an object. A Computed Tomography (CT) scan, also known as a CAT scan (Computed Axial Tomography scan), is a Helical Tomography, which traditionally produces a 2D image of the structures in a thin section of the body. It uses X-ray, which is ionizing radiation. Although the actual dose is typically low, repeated scans should be limited. In dentistry, implant dentistry in specific, there is a need for 3D visualization of internal anatomy. The internal visualization is mainly based on CT scanning technologies. The most important technological advancement which dramatically enhanced the clinician\u27s ability to diagnose, treat, and plan dental implants has been the CT scan. Advanced 3D modeling and visualization techniques permit highly refined and accurate assessment of the CT scan data. However, in addition to imperfections of the instrument and the imaging process, it is not uncommon to encounter other unwanted artifacts in the form of bright regions, flares and erroneous pixels due to dental bridges, metal braces, etc. Currently, removing and cleaning up the data from acquisition backscattering imperfections and unwanted artifacts is performed manually, which is as good as the experience level of the technician. On the other hand the process is error prone, since the editing process needs to be performed image by image. We address some of these issues by proposing novel registration methods and using stonecast models of patient\u27s dental imprint as reference ground truth data. Stone-cast models were originally used by dentists to make complete or partial dentures. The CT scan of such stone-cast models can be used to automatically guide the cleaning of patients\u27 CT scans from defects or unwanted artifacts, and also as an automatic segmentation system for the outliers of the CT scan data without use of stone-cast models. Segmented data is subsequently used to clean the data from artifacts using a new proposed 3D inpainting approach