55 research outputs found

    A new Edge Detector Based on Parametric Surface Model: Regression Surface Descriptor

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    In this paper we present a new methodology for edge detection in digital images. The first originality of the proposed method is to consider image content as a parametric surface. Then, an original parametric local model of this surface representing image content is proposed. The few parameters involved in the proposed model are shown to be very sensitive to discontinuities in surface which correspond to edges in image content. This naturally leads to the design of an efficient edge detector. Moreover, a thorough analysis of the proposed model also allows us to explain how these parameters can be used to obtain edge descriptors such as orientations and curvatures. In practice, the proposed methodology offers two main advantages. First, it has high customization possibilities in order to be adjusted to a wide range of different problems, from coarse to fine scale edge detection. Second, it is very robust to blurring process and additive noise. Numerical results are presented to emphasis these properties and to confirm efficiency of the proposed method through a comparative study with other edge detectors.Comment: 21 pages, 13 figures and 2 table

    Software de procesado de imágenes procedentes de un sonar de barrido lateral en exploración submarina

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    Digital images provided by onboard sidescan sonar in an unmanned undersea vehicle (UUV), are usually poor in their resolution. There are two commercial expensive solutions for this trouble: the first one is the use of high resolution multibeam sidescan sonar, the second one consists in the use of bathymetric sonar. It is evident that for spanish university these solutions exceeds the economical budget and needs a generous external support. This work shows an economical solution for this problem by using digital image processing techniques under MATLAB environment. Results are comparable in quality with the commercial expensive hardware solutions. The application presented here is easy to use and has been developed under “user friendly” philosophy and could be operated for users at any level. This work is the first step for future lines of work in underwater recognition of objects

    Image enhancements for low-bitrate videocoding

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    Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 71).by Brian C. Davison.M.Eng

    Analysis of Image Sequence Data with Applications to Two-Dimensional Echocardiography

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    Digital two-dimensional echocardiography is an ultrasonic imaging technique that is used as an increasingly important noninvasive technique in the comprehensive characterization of the left ventricular structure and function. Quantitative analysis often uses heart wall motion and other shape attributes such as the heart wall thickness, heart chamber area, and the variation of these attributes throughout the cardiac cycle. These analyses require the complete determination of the heart wall boundaries. Poor image quality and large amount of noise makes computer detection of the boundaries difficult. An algorithm to detect both the inner and outer heart wall boundaries is presented. The algorithm was applied to images acquired from animal studies and from a tissue equivalent phantom to verify the performance. Different approaches to exploiting the temporal redundancy of the image data without making use of results from image segmentation and scene interpretation are explored. A new approach to perform image flow analysis is developed based on the Total Least Squares method. The result of this processing is an estimate of the velocities in the image plane. In an image understanding system, information acquired from related domains by other sensors are often useful to the analysis of images. Electrocardiogram signals measure the change of electrical potential changes in the heart muscle an d provide important information such as the timing data for image sequence analysis. These signals are frequently plagued by impulsive muscle noise and background drift due to patient movement. A new approach to solving these problems is presented using mathematical morphology. Experiments addressing various aspects of the problem, such as algorithm performance, choice of operator parameters, and response to sinusoidal inputs, are reported

    Infrared microscopy and liquid chromatography applied to problems in forensics and bioanalytical chemistry

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    The main objectives of the research described in this dissertation are: (1) development of a methodology to prepare thin sections of automotive paint samples that involve exposing the edge of the sample using a microtome for infrared image analysis, (2) implementation of infrared library searching to match attenuated total reflection spectra obtained from an IR microscope to a transmission infrared spectral library, and (3) development of a reversed phase liquid chromatographic method to simultaneously detect renal cell carcinoma cancer biomarkers in urine. In one study, infrared imaging microscopy was investigated as a potential method to improve both the speed and accuracy of forensic automotive paint analysis. This is achieved by scanning across the layers of a paint sample using an infrared imaging microscope followed by decatenation of the image using alternating least squares. This approach, not only eliminates the need to hand section and analyze each paint layer separately, but also ensures that the IR spectrum of each layer is "pure" and not a mixture as a result of sampling too to the boundary between two paint layers a scalpel is used to hand section a paint chip to separate the individual layers. In a second study, an isocratic reversed phase liquid chromatographic method was developed to simultaneously detect and quantify three potential renal cell carcinoma biomarkers in urine which are present at relatively high concentrations: quinolinic acid, gentisic acid and 4-hydroxybenzoic acid. Using a methanol or butanol in water mobile phase with 0.6% acetic acid and a Zorbax C18 column, baseline resolution for creatinine and the three biomarkers in synthetic urine was achieved when water rich mobile phases were used. Detection of creatinine and the three biomarkers in urine using the proposed method was limited by background from the urine matrix for the later eluting compounds and from the dead marker for the earlier eluting compounds

    Aeronautical Engineering: A continuing bibliography with indexes, supplement 107

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    Reports, articles, and other documents introduced into the NASA scientific and technical information system in February 1979 are listed in this bibliography

    Development and optimization of the production process of a recombinant human protein by high-throughput techniques. Sviluppo e ottimizzazione del processo di produzione di una proteina umana ricombinante attraverso l'utilizzo di tecniche high-throughput.

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    Most biotechnology unit operations are complex with numerous process variables, feed material and raw material attributes that play significant impact on the performance of a process. Design of Experiment (DoE)-based approach together with HTPD (High-Throughput Process Development) techniques offer a solution to this issue allowing for an efficient estimation of effects and interactions by employing a minimal number of experiments. In the first part of the PhD work the HTPD approaches combined to statistical software were adopted in order to optimize a production process of a 340 kDa therapeutic recombinant protein expressed in PER.C6 cell line. The optimization of the purification process was performed by increasing the yield and by reducing the HCPs, residual DNA and viral contamination in order to obtain a fully compliant GMP process. This was achieved by introducing an arginine washing step during the capture on AEX resin and by reducing the concentration of phosphate in elution buffer in the intermediate step on hydroxyapatite, preventing the co-elution of the protein of interest and rDNA. A decrease of rDNA was then obtained by a membrane AEX step (by flow-through mode). Finally, two viral reduction steps (by thermal inactivation and filtration) were used in order to satisfy ICH Q5A guidelines. In the second part of the work, the DoE and HTPD technology were used as a \u201ctool box\u201d inside a step by step \u201cdecision tree\u201d in order to lead the experimenter in a well defined path with the purpose of purifying and formulate any protein of interest. The protein used to test the procedure was a 13 kDa protein expressed in E. coli as inclusion bodies. The novel process allowed to obtain a pure and active preparation of the protein compliant to GMP requirements

    NASA Aircraft Controls Research, 1983

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    The workshop consisted of 24 technical presentations on various aspects of aircraft controls, ranging from the theoretical development of control laws to the evaluation of new controls technology in flight test vehicles. A special report on the status of foreign aircraft technology and a panel session with seven representatives from organizations which use aircraft controls technology were also included. The controls research needs and opportunities for the future as well as the role envisioned for NASA in that research were addressed. Input from the panel and response to the workshop presentations will be used by NASA in developing future programs
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