Wavelet Based Filtering of Electrocardiograms

Tato dizertační práce pojednává o možnostech využití vlnkových transformací pro odstranění širokopásmového svalového rušení v signálech EKG. V práci jsou nejprve rozebrány vlastnosti signálů EKG a především nejčastěji vyskytující se typy rušení. Dále je představena teorie vlnkových transformací a ukázány návrhy jednoduchého vlnkového filtru i sofistikovanější varianty využívající wienerovské filtrace vlnkových koeficientů. Další část práce je věnována návrhu vlastního filtru, který vychází právě z wienerovské vlnkové filtrace a je doplněn algoritmy zajišťujícími plnou adaptibilitu jeho parametrů při změně vlastností vstupního signálu. Vhodné parametry navrženého systému jsou hledány automatickým způsobem a algoritmus je testován na kompletní standardní databázi elektrokardiogramů CSE, kde dosahuje výrazně lepších výsledků než další srovnávané publikované metody.This dissertation deals with possibilities of using wavelet transforms for elimination of broadband muscle noise in ECG signals. In this work, the characteristics of ECG signals and particularly the most frequently occurring type of interference are discussed firstly. The theory of wavelet transforms is also introduced and followed by design of the simple wavelet filter and the more sophisticated version with wiener filtering of wavelet coefficients. Next part is devoted to the design of our filter, which is based on wavelet wiener filtering and is complemented by algorithms that ensure full adaptability of its parameters when the properties of the input signal are changing. Suitable parameters of the proposed system are searched automatically and the algorithm is tested on the complete standard electrocardiograms database CSE, where it achieves significantly better results than other published methods.

Machine Learning Approach for Comparative Analysis of De-Noising Techniques in Ultrasound Images of Ovarian Tumors

Ovarian abnormalities such ovarian cysts, tumors, and polycystic ovaries are one of the serious disorders affecting women's health. In ultrasound imaging of ovarian abnormalities, noise during capturing of the image and its transmission process frequently corrupts the image. In order to make the best judgments possible at the appropriate moment, ovarian cysts in females must be accurately detected.  In computer aided diagnosis of ovarian tumors, preprocessing is a very important step. In preprocessing, de-noising of medical images is a particularly a difficult task since it must be done while maintaining image features that are essential for diagnosis. In this research work we are using various denoising filters on ultrasound images of ovarian tumors. For different noise denoising techniques, performance measures like MSE, PSNR, SSIM, and UQI etc. are calculated. According to experimental findings, Block matching 3-D filter outperforms all other methods. Radiologists can better diagnose the condition with the use of this computer-assisted system

Elimination the impact of heat stress by supplementation of antioxidants into diet of duroc boars

The aim of this experiment was to find out, if is it possible to eliminate the impact of heat stress on quality of Duroc boar ejaculate by the addition of complex of antioxidants (Selenium, Zinc, Vit. C and Vit. E) into the basic diet. The experiment was carried out at the station of insemination in Velke Mezirici (Czech Republic) from May to September. For the study were chosen 12 Duroc boars, of approximately the same age and weight, and were divided into two groups. The control group (n = 6) was fed only by basic diet, the experimental group (n = 6) was fed by basic diet with the supplementation of antioxidants in amount: 0.5 mg selenium (seleno-methionine), 70 mg zinc (zinc-methionine), 70 mg vit. E (alpha-tocopherol) and 350 mg vit. C (L-ascorbic acid) per kilogram of basic diet. Monitored parameters of ejaculate was volume of ejaculate (ml), concentration of sperm (106/ml), total rate of sperm (109), motility of sperm (%) and amount of morphologically abnormal sperm (%). The control group reported slight increase in volume of ejaculate (of 19 %), which is common in summer months. At the same time was the concentration of sperm unstable, during August there was an increase of 15 %, but during September concentration decreased below the initial amount. Motility was around 69 % during whole experiment. There was an increase (of 15 %) in amount of morphologically abnormal sperm, but the result was insignificant. The experimental group had a higher volume of ejaculate, but the diagram of volume of ejaculate was almost the same with the control group. Concentration of sperm increased after the supplementation of antioxidants (of 23 %) and during the experiment decreased only slightly. Motility was about average amount 70 % and was not various during the experiment. In amount of morphologically abnormal sperm there was an increase about 12 %. According to the results, the supplementation of antioxidants had no significant effect on improving of semen quality. But the addition could have a positive effect to stable the parameters of ejaculate.O

Image analysis for correction of electron microscopes

Tato práce se zabývá fyzikální podstatou korekcí elektronového mikroskopu a matematickými metodami zpracování obrazu potřebnými pro jejich kompletní automatizaci. Jedná se o různé typy ostření, korekci astigmatismu, centrování elektronového svazku či stabilizaci obrazu. Mezi popsané matematické metody patří různé metody zjištění ostrosti a astigmatismu, jak s použitím Fourierovy transformace, tak bez ní, dále metody detekce hran, operace s histogramem a lícování snímků, tedy zjišťování prostorových transformací v obraze, včetně zmínky o optimalizačních metodách. Tato práce obsahuje podrobný popis matematických metod, jejich zhodnocení na základě testovací „offline“ aplikace, popis algoritmů jejich implementace do reálného elektronového mikroskopu a výsledek testu na reálném mikroskopu v podobě videozáznamu z obrazovky ovládacího počítače.This thesis describes the physical nature of corrections of an electron microscope and mathematical methods of image processing required for their complete automation. The corrections include different types of focusing, astigmatism correction, electron beam centring, and image stabilisation. The mathematical methods described in this thesis include various methods of measuring focus and astigmatism, with and without using the Fourier transform, edge detection, histogram operations, and image registration, i.e. detection of spatial transformations in images. This thesis includes detailed descriptions of the mathematical methods, their evaluation using an “offline” application, descriptions of the algorithms of their implementation into an actual electron microscope and results of their testing on the actual electron microscope, in the form of a video footage grabbed from its control computer’s screen.

Cutting of measuring hard-metal triple contacts by ED technology

Práce pojednává o nekonvenčních metodách obrábění zaměřená především na elektroerozivní drátové řezání. V úvodu jsou popsány základní principy a podstata elektroerozivního obrábění. Praktická část je zaměřena na řešení stávajícího problému – snížení zmetkovitosti měřících trojdoteků při výrobě ve firmě Kovo Jančo.This work deals with unconventional machining methods focused primarily on the wire EDM cutting. The introduction describes the basic principles and essence of electrical discharge machining. The practical part is focused on solving the current problem - reducing scrap of measuring triple contacts in the production company Kovo Jančo.