A measuring system evaluating a Point Spread Function generated in an ultrasonographic image by scanning a spherical target was developed. The target is moved in measuring bath filled by water over scanned volume via 3D computer controlled positioning system. A video signal obtained is converted to digital form and analyzed by original software to derive various objective parameters of the imager as follows: Focal areas in both the azimuth and the elevation directions, Ultrasound scanning lines visualisation, Manufacturer preloaded TGC, Width of the scanning plane, Side lobe levels and Amplification uniformity in the azimuth direction. The method was verified by testing 18 different equipments in 282 measurements. Samples of particular measurement results in form of graphical outputs are included. Medical and physiological impacts of this approach are discussed., L. Doležal, J. Mazura, J. Tesařík, H. Kolářová, D. Korpas, S. Binder, J. Hálek., and Obsahuje bibliografii
Reliable observations are the prerequisite for high-precision GNSS data processing. Data quality evaluation at the pre-processing procedure can help the user to identify the weakness of the observations. The open source software package G-Nut/Anubis developed at Geodetic Observatory Pecny (GOP) is introduced and used for the evaluation of long-term BeiDou/GPS signal. Several key indicators are selected to evaluate the BeiDou/GPS observations. Quantitative analysis shows that more than 100 stations can achieve 6-hour standalone BeiDou positioning at least. The completeness of the BeiDou phase and code observations at three frequencies is higher than that of the GPS observations in the selected station which is mainly attributed to the high elevation observations from GEO and IGSO satellites. Qualitative analysis shows that the multipath effects for pseudorange observations are correlated with signal, receiver types and firmware versions besides the station environment. Users attempting to improve the pseudorange observations by multipath filter should pay attention also to the receiver-specific settings. Cycle slip counts are used to indicate the quality of carrier-phase observations. Results show that BeiDou C05 satellite is more affected by the cycle slips, in particular the third frequency observables. For GPS, the third frequency is more robust compared to the legacy frequencies. Comprehensive single point positioning results show that positioning accuracy for BeiDou is worse than that of GPS, which is mainly caused by less active satellites, worse geometry and the larger errors in the broadcast ephemeris. The BeiDou positioning accuracy was further degraded by the C13/C15 satellite and dominated by large clock errors. Broadcast evaluation shows that the BeiDou orbit errors are related to the constellations. Overall, the orbit precision for both GPS and BeiDou has been gradually improved. Outliers were observed for navigation records assigned with the healthy status, especially for BeiDou broadcast orbits. and Zhao Lewen, Dousa Jan, Vaclavovic Pavel, Ye Shirong, Xia Fengyu.
In practise a corrugation tests are widely used for evaluation a flatglass quality during its mass production. Recently, these tests have been based on a subjective standards comparison with the ripple of the zebra-plate image reflected by the glass-sheet sample. Tests in a continuous production process are performed even several times per hour under usual conditions. Our research aim consists in an objectification of corrugation quantity replacing the subjective observer by digital camera and processing unit, all verified routinely in the production process. For a corrugation analysis the unique software was proposed and developed using the Matlab environment, including the data acquisition in service. The code is compiled as an independently executable module. The principle of the method rests in the detection of boundary lines between light and dark areas of the sample image and their evaluation employing statistical approach, curve rectification and determination of its fractal dimension. The quality parameter obtained in such a way and recalculated by means of weighted coefficients is in the accord with the results previously achieved using the subjective methodology. and Pro hodnocení vlnitosti skla je v praxi využíván tzv. test zvlnění (corrugation test), který je založen na pozorování míry zvlnění odrazu zebra-desky od vzorku skla a subjektivním porovnáním s etalony. Tento test se v běžných provozních podmínkách provádí i několikrát za hodinu při nepřetržitém provozu. Cílem výzkumu je objektivně kvantifikovat vlnitost nahrazením pozorovatele digitálním fotoaparátem a vyhodnocovací jednotkou a zařízení zprovoznit v praxi. V rámci výzkumu byl vyvinut software pro kvantitativní analýzu nazvaný Vlnitost v prostředí Matlab a pro účely sběru dat v provoze byl kompilován do samospustitelného programu. To znamená, že program není závislý na prostředí Matlab, ale pouze na jeho tzv. knihovnách, které jsou spolu s programem nainstalovány na počítači. Systém umožňuje ovládání fotoaparátu přímo z programu Vlnitost. Program je založen na detekci křivek rozhraní mezi světlem a stínem odraženého obrazu od vzorku a vyhodnocení těchto křivek. Pro hodnocení je užíváno několika parametrů včetně statistických, délek křivky a fraktální dimenze. Výsledná jakost je pak přepočtena pomocí váhových koeficientů a je shodná s již dříve zavedenou škálou pro subjektivní hodnocení vlnitosti. Modifikovaná metodika je používána také pro porovnání a kvantifikaci změn povrchů materiálů v metalografických výbrusech probíhajících vlivem působení korozního prostředí a fraktální geometrie je také užívána pro popis dat ze senzorů v průmyslové praxi.