On computing the exact euclidean distance transform on rectangular and hexagonal grids

In this paper we prove an equivalence relation between the distance transform of a binary image, where the underlying distance is based on a positive definite quadratic form, and the erosion of its characteristic function by an elliptic poweroid structuring element. The algorithms devised by Shih and Mitchell [18] and Huang and Mitchell [7], for calculating the exact Euclidean distance transform (EDT) of a binary digital image manifested on a square grid, are particular cases of this result. The former algorithm uses erosion by a circular cone to calculate the EDT whilst the latter uses erosion by an elliptic paraboloid (which allows for pixel aspect ratio correction) to calculate the square of the EDT. Huang and Mitchell's algorithm [7] is arguably the better of the two because: (i) the structuring element can be decomposed into a sequence of dilations by 3 x 3 structuring elements (a similar decomposition is not possible for the circular cone) thus reducing the complexity of the erosion, and (ii) the algorithm only requires integer arithmetic (it produces squared distance). The algorithm is amenable to both hardware implementation using a pipeline architecture and efficient implementation on serial machines. Unfortunately the algorithm does not directly transpose to, nor has a corresponding analogue on, the hexagonal grid (the same is also true for Shih and Mitchell's algorithm [7]). In this paper, however, we show that if the hexagonal grid image is embedded in a rectangular grid then Huang and Mitchell's algorithm [7] can be applied, with aspect ratio correction, to obtain the exact EDT on the hexagonal grid

Classification in scale-space: Applications to texture analysis

this paper we propose a technique for classifying images by modeling features extracted at different scales. Specifically, we use texture measures derived from Pap Smear cell nuclei images using a Grey Level Co-occurrence Matrix (GLCM). For a texture feature extracted from the GLCM at a number of distances we hypothesise that by modeling the feature as a continuous function of scale we can obtain information as to the shape of this function and hence improve its discriminatory power. This hypothesis is compared to the traditional method of selecting a given number of the best single distance measures. It is found, on the limited data set available, that the classification accuracy can be improved by modeling the texture features in this way

Increasing the efficiency of manufacturing elements of turbo machine face impulse seals by applying functional coatings

Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.02.08 – технологія машинобудування. – Національний технічний університет «Харківський політехнічний інститут», Харків, 2019. Дисертація присвячена вирішенню науково-технічної задачі забезпечення працездатності торцевих імпульсних ущільнень (ТІУ) турбомашин шляхом удосконалення технології виготовлення кілець із композиційних матеріалів, що поєднують у собі механічну міцність основи та захисні властивості покриттів. Проведено аналіз технології виготовлення й особливостей експлуатації ТІУ, з метою пошуку технологічних методів, які дозволяють створювати на підкладках зі сталей і сплавів функціональні покриття із заданими експлуатаційними властивостями. Розроблено методику спрямованого вибору технології забезпечення необхідної якості робочих поверхонь кілець ТІУ залежно від умов роботи ущільнення й властивостей навколишнього середовища. Удосконалено технологію виготовлення елементів ТІУ, які працюють в агресивних середовищах і виготовляються зі сталевих, нікелевих та бронзових сплавів, за рахунок застосування енергоефективних та екологічно чистих методів, альтернативних хіміко-термічній обробці. Розроблено новий метод збільшення товщини шару підвищеної твердості шляхом формування на попередньо зміцнених методом цементації електроерозійним легуванням торцевих поверхнях кілець ТІУ комбінованих електроерозійних покриттів. Проведено трибологічні дослідження та дослідження параметрів якості поверхневих шарів, сформованих методом іонного азотування, конденсованого іонного бомбардування та карбонітрацією. Розроблено метод зниження фретинг-корозії для контактуючих поверхонь ущільнювальних елементів ТІУ. Розроблено технологічні рекомендації виготовлення ТІУ залежно від умов роботи та перекачуваного середовища. Економічний ефект від впровадження основних положень роботи у виробництво становить 450 тис. грн.Thesis for granting the Degree of Candidate of Technical sciences in specialty 05.02.08 - Manufacturing Engineering. - National Technical University "Kharkiv Polytechnic Institute", 2019. The dissertation is devoted to the solution of the scientific and technical problem of ensuring the efficiency of face impulse seals (FIS) of turbomachines by improving the technology of manufacturing rings made of composite materials, which combine the mechanical strength of the substrate and the protective properties of coatings. An analysis of manufacturing technology and features of FIS operation was conducted in order to search for technological methods that allow to create functional coatings with specified operational properties on substrates of steels and alloys. The technique of directional choice of technology for ensuring the required quality of the working surfaces of the FIS rings, depending on the working conditions of the seal and the environmental properties, is developed. The technology of manufacturing FIS elements that work in corrosive environments and made of steel, nickel and bronze alloys has been improved due to the use of energy-efficient and environmentally friendly methods, alternative to chemical-thermal treatment. A new method of increasing the thickness of the layer of increased hardness by forming on the pre-strengthened cementing method by electro-erosion doping of the end surfaces of the FIS rings of the combined electro-erosion coatings is developed. Tribological researches and investigations of quality parameters of surface layers formed by the method of ion nitriding, condensed ion bombardment and carbonitration were carried out. The method of reducing the fretting corrosion for the contact surfaces of the sealing elements of the FIS has been developed. Technological recommendations for the production of FIS depending on the operating conditions and the pumped medium are developed. The economic effect of the introduction of the main provisions of work in production is 450 000 UAH

Development and calibration of a constrained resource health outcomes simulation model of hospital-based glaucoma services

Health service delivery and organization often develops in an ad hoc manner, in response to unplanned changes in referral patterns, technologies and system-level factors. We developed a discrete event simulation model for the analysis of health services in a routine clinical setting, with the objective of predicting the process impact of variations to current forms of service delivery and organization. As a case study, we use glaucoma services provided at the Royal Adelaide Hospital, South Australia. Both clinical and administrative hospital data were used to populate and calibrate the model. A random search strategy of a constrained parameter space identified convergent input parameter sets, representing the current operation of glaucoma services at the hospital. Analyses of alternative service configurations showed that extending the patient booking cycle, and review times for stable patients lowered patient numbers per clinic and decreased delays. Applied health services can be successfully simulated and calibrated, providing a basis for analyses of patient throughput, and potentially the economic evaluation of alternative approaches to organizing such services.Glenis J. Crane, Steven M. Kymes, Janet E. Hiller, Robert Casson and Jonathan D. Karno

Complementarity-Preserving Fracture Morphology for Archaeological Fragments

We propose to employ scale spaces of mathematical morphology to hierarchically simplify fracture surfaces of complementarity fitting archaeological fragments. This representation preserves complementarity and is insensitive to different kinds of abrasion affecting the exact fitting of the original fragments. We present a pipeline for morphologically simplifying fracture surfaces, based on their Lipschitz nature; its core is a new embedding of fracture surfaces to simultaneously compute both closing and opening morphological operations, using distance transforms

Characteristic wave detection in ECG signal using morphological transform

<p>Abstract</p> <p>Background</p> <p>Detection of characteristic waves, such as QRS complex, P wave and T wave, is one of the essential tasks in the cardiovascular arrhythmia recognition from Electrocardiogram (ECG).</p> <p>Methods</p> <p>A multiscale morphological derivative (MMD) transform-based singularity detector, is developed for the detection of fiducial points in ECG signal, where these points are related to the characteristic waves such as the QRS complex, P wave and T wave. The MMD detector is constructed by substituting the conventional derivative with a multiscale morphological derivative.</p> <p>Results</p> <p>We demonstrated through experiments that the Q wave, R peak, S wave, the onsets and offsets of the P wave and T wave could be reliably detected in the multiscale space by the MMD detector. Compared with the results obtained via with wavelet transform-based and adaptive thresholding-based techniques, an overall better performance by the MMD method was observed.</p> <p>Conclusion</p> <p>The developed MMD method exhibits good potentials for automated ECG signal analysis and cardiovascular arrhythmia recognition.</p