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EN
The paper concerns an analysis regarding geometry of a grinding wheel used in grinding of cylindrical worm threads characterized by various geometry. It presents geometrical and physical factors having impact on the dressing process and quality of the grinding wheel. In particular, an attention is paid on the accuracy of a grinding wheel’s outline if it is approximated by linear interpolation line segments which are obtained in the case of dressing on a CNC machine tool. On the basis of two grinding wheel outlines (Archimedes and circular-arched one), the relevance of the length of the segment line on the geometrical accuracy of wheel’s outline has been presented. In the case of development of a wheel dresser path on the CNC machine tool, the necessity of a customized approach has also been indicated.
EN
The objective of this work is to set up a methodology that considers missing data from a connected heartbeat sensor in order to propose a good replacement methodology in the context of heart rate variability (HRV) computation. The framework is a research project, which aims to build a system that can measure stress and other factors influencing the onset and development of heart disease. The research encompasses studying existing methods, and improving them by use of experimental data from case study that describe the participant’s everyday life. We conduct a study to modelize stress from the HRV signal, which is extracted from a heart rate monitor belt connected to a smart watch. This paper describes data recording procedure and data imputation methodology. Missing data is a topic that has been discussed by several authors. The manuscript explains why we choose spline interpolation for data values imputation. We implement a random suppression data procedure and simulate removed data. After that, we implement several algorithms and choose the best one for our case study based on the mean square error.
PL
Podczas rejestracji ruchu z zastosowaniem pasywnego systemu akwizycji ruchu, w trajektorii danego markera może powstać luka, którą w procesie obróbki danych należy uzupełnić. Stosuje się w tym celu różne algorytmy interpolacji. Artykuł przedstawia trzy różne metody interpolacji: liniową, wielomianem Lagrange’a drugiego stopnia oraz piątego stopnia. W oryginalnych danych 3D zostały utworzone dziury, które następnie uzupełniono trzema metodami. Każda metoda została oceniona za pomocą miary odległości Euklidesa dla trzech wymiarów danych oryginalnych oraz po uzupełnieniu trajektorii. W artykule przedstawiono także program do uzupełniania trajektorii, zaimplementowany w języku C++. Przedstawiona analiza dotyczy uzupełnianie trajektorii wybranych markerów z modelu Plug-in Gait podczas chodu osoby.
EN
During the motion registration using passive motion capture system in the marker’s trajectory a gap may appear, which in the data post-processing should be filled in. Various interpolation algorithms are used for this purpose. This article presents three different interpolation methods: linear, polynomial of Lagrange of second degree and fifth degree. In the original 3D data the holes have been created, which are then filled in by mentioned methods. Each method was evaluated by measuring the Euklides distance for three dimensions of the original and interpolated data. The article presents the program to interpolate gaps in the trajectory, implemented in C ++ language. The analysis concerns the interpolation of selected marker’s trajectory which belongs to the Plug-in Gait model while performing walking.
PL
W opracowaniu przedstawiono zmodyfikowaną przez autorów niniejszej pracy postać macierzy transformacji w metodzie Vincenta i Zhanga do homogenizacji średnich dobowych wartości temperatury. Szczególną uwagę zwrócono na opisanie sposobu otrzymania nowej postaci macierzy. Dokonano porównania wyników homogenizacji szeregów czasowych wykorzystując wymienioną metodę przed i po modyfikacji. Wyznaczono wartości poprawek dobowych otrzymanych dla obydwu postaci macierzy transformacji dla różnych zestawów poprawek miesięcznych
EN
Homogeneous, continuous and long-term sets of meteorological elements are base of climatological research. Unfortunately sets characterized by those features are very rare. In resent years there has been an enormous development of technics which enable us to recontruct and homogenize time-series. One of those concepts which enables to homogenize time series of mean daily temperature values without referring to reference-series is proposed by Vincent and Zhang. The core of this method is transformation matrix educed by Sheng and Zwiers. The form of this matrix drow our attention in few points. In this paper the authors present alternative form of the transformation matrix. Additionally eduction algorhytm of the matrix is given. Both matrixes were compared. The mean daily temperature values were computed using new form of the matrix. The results are better fitted into conditions of Vincent and Zhang for homogenization methods. Both matrixes were implemented into new software application Homogenizator v.1.0. This software was used to homogenize Lodz's mean daily temperature values sets (Wibig, Rzepa 2007a).
EN
In this paper, a fast graphics process unit (GPU) based ray casting algorithm is presented to improve image quality. A linear interpolation is used to estimate the intersection between a ray and isosurfaces. Thus, resampling artefacts is greatly reduced and the performance is not influenced. An iterative estimation is presented to further improve image quality. According to the distance the ray goes across, z values in the z-buffer are modified to implement hiding of hybrid scenes. Experimental results show that the algorithm can produce high quality images at interactive frame rates and implement hiding of hybrid scenes very well.
7
Content available remote Wow defect reduction based on interpolation techniques
EN
In this paper the capacity of non-uniform sampling rate conversion techniques, invo1ving different interpolation methods, aimed at wow defect reduction, is examined. Involved are: linear interpolation, tour po1ynomial-based interpolation methods and the windowed sincbased method. The examined polynomial methods are: Lagrange interpolation, polynomial fitting with additional noise reduction, Hermitan and Spline. The performance of an artificially distorted audio signal, restored using non-uniform resampling, is evaluated on the basis of standard audio defect measurement criteria and compared for all of the aforementioned interpolation methods. The chosen defect descriptors are: total harmonic distortion, total harmonic distortion plus noise and signal to noise ratio.
PL
Tomografia komputerowa (TK) ze względu na precyzję jest obecnie techniką powszechnie stosowaną w obrazowaniu wątroby i diagnozowaniu związanych z nią chorób. Metody wspomagane komputerowo, które mają za zadanie ułatwić wydzielanie kształtu organów z obrazów medycznych, a także pomóc w diagnozowaniu jednostek chorobowych, są obecnie intensywnie rozwijane. W pracy zaprezentowano autorską metodę automatycznego wyznaczania przybliżonego konturu wątroby, polegającą na liniowej interpolacji współrzędnych brzegu, za pomocą skończonej liczby połączonych ze sobą łamanych, tworzących figurę zamkniętą. W artykule zaprezentowano też anatomię radiologiczną i metodykę badań dotyczących tomografii komputerowej wątroby.
EN
Computed Tomography (CT) has been widely used for liver disease diagnosis. CT scans can bring precise inspection and shape extraction during examination. Computer-assisted methods to help extract organs and classify diseases from medical seans has received considerable interests over the past years. As a first step of gathering necessary data we need to isolate or segment the liver boundary within CT liver image. In the paper a fully automated method to detect a liver contour has been presented. We propose an author's algorithm based on piece-wise linear interpolation which extracts liver boundary. The paper provides necessary background of radiological anatomy and imaging of the liver.
9
Content available remote Morphological operations with subpixel resolution on digital images
EN
In many defect inspection systems computer vision pattern matching techniques are applied. These techniques require the use of different morphological operations. In many situations, pattern images generated by classical morphological operations do not allow to detect defects in images. Small defects of pixel size can also be left unnoticed when using such pattern images. The purpose of this paper is to combine classical morphological operations with a linear interpolation process on digital images to generate these pattern images. It is possible to employ structuring elements of any size to carry out morphological operations on continuous signals. However, on gigital images or discrete signals, the size of the structuring element should be greater than pixel size. The approach described in this paper applies classical morphological operations on reconstructed images at subpixel level to generate [pattern images. In such circumstances, we can compare this procedure with the effect produced by the use of structuring elements smaller than pixel size.
PL
W artykule omówiono problem interpolacji liniowej zarysu owalnego kształtowanego przez układ CNC i elektryczny serwonapęd bezpośredni z silnikiem liniowym w procesie toczenia tło-ków do silników spalinowych. Duże przyspieszenia suportu poprzecznego podczas toczenia nie-okrągłego sprawiają, że w sumarycznym błędzie zarysu dominuje uchyb przyspieszeniowy. Wykazano kompensacyjny charakter oddziaływania geometrycznego uchybu interpolacji liniowej na uchyb przyspieszeniowy. Spełnia ona w pewnym sensie funkcję sterownika FF (Feed Forward) ze sprzężeniem w przód od przyspieszenia [1].
EN
The paper presents the problem of linear interpolation of oval outline formed by CNC system and direct electric servo drive with linear motor in the turning process pistons for combustion engines. High values of acceleration of crosswise slide during the oval turning, exceeding 30 ms(-2) cause the domination of acceleration deviation in summary error. There has been shown compen-satory character of influence of geometrical deviation of linear interpolation on the acceleration deviation. It substitutes in a way the FF controller (Feed Forward) with the feed forward from acceleration [1].
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