20 research outputs found
Week of Czech Youth
No full textSegment from Český zvukový týdeník Aktualita (Czech Aktualita Sound Newsreel) issue no. 29A from 1944 was shot during the Week of Czech Youth event organised by the Board of Trustees for the Education of Youth and held from 1 to 9 July. The programme included a concert held on Old Town Square on 8 July. The orchestra and choir consisted of several hundred young musicians and singers. Minister of Education and People´s Enlightenment and Chairman of the Board Emanuel Moravec and Deputy Mayor Joseph Pfitzner watched the event from the balcony of the Old Town Hall. The Board of Trustees´ youth set out from the square in a parade through the streets of Prague. The following day, a sports afternoon took place at Strahov Stadium. Guests of honour included Prime Minister Jaroslav Krejčí and the General Secretary of the Board František Teuner. Emanuel Moravec spoke to the participants. The programme included women´s floor exercises, track and field races and women in stylised costumes dancing to folk songs. The event was concluded with the athletes and audience paying homage to Adolf Hitler
An algorithm for the automatic identification of left ventricular internal wall edges in digital echocardiographic image sequences
No full textS.221 - 226Im vorliegenden Beitrag wird ein automatisiertes Verfahren zur Endokarderkennung in digitalen echokardiographischen Bildsequenzen vorgestellt. Das vorgeschlagene Verfahren gliedert sich modular in drei Verarbeitungsschritte auf und wurde in der Programmiersprache C unter UNIX implementiert. Es umfaßt die Verwendung eines anwendungsspezifisch entworfenen adaptiven Orts-Zeit-Filters für die Rauschreduktion in echokardiographischen Bildsequenzen, eine lokale 3-D-Grauwertäqualisation zur Kontrastanhebung und die Segmentierung des linken Ventrikels mit Hilfe eines Gebietswachstumsverfahrens. Beim Entwurf des adaptiven Orts-Zeit-Filters wurde in Betracht gezogen, daß das Hintergrundrauschen in tangentialer Richtung korreliert ist, verursacht durch die Ablenkung der Schallstrahlen beim Auftreffen auf Grenzflächen, die einen hohen Impedanzsprung aufweisen. Mit Hilfe des anwendungspezifisch entworfenen Filters wird das Hintergrundrauschen, ohne die ventrikularen Konturen zu degradieren, erfolgr eich reduziert. Die vorgestellten Simulationsergebnisse heben die Leistungsfähigkeit des vorgeschlagenen Verfahrens in exemplarischer Weise hervor.43Nr.7-
Automatic texture segmentation for content-based image retrieval application
No full textIn this article, a brief review on texture segmentation is presented, before a novel automatic texture segmentation algorithm is developed. The algorithm is based on a modified discrete wavelet frames and the mean shift algorithm. The proposed technique is tested on a range of textured images including composite texture images, synthetic texture images, real scene images as well as our main source of images, the museum images of various kinds. An extension to the automatic texture segmentation, a texture identifier is also introduced for integration into a retrieval system, providing an excellent approach to content-based image retrieval using texture features
Unsupervised texture segmentation using multiresolution Markov random fields
No full textIn this thesis, a multiresolution Markov Random Field (MMRF) model for
segmenting textured images without supervision is proposed. Stochastic relaxation
labelling is adopted to assign the class label with highest probability
to the block (site) being visited. Class information is propagated from low
spatial resolution to high spatial resolution, via appropriate modifications to
the interaction energies defining the field, to minimise class-position uncertainty.
The thesis contains novel ideas presented in Chapter 4 and 5, respectively.
In Chapter 4, the Multiresolution Fourier Transform (MFT) is used
to provide a set of spatially localised texture descriptors, which are based
on a two-component model of texture, in which one component is a deformation,
representing the structural or deterministic elements and the other
is a stochastic one. Experiments show that the algorithm is efficient in alleviating
class-position uncertainty via data propagation across resolutions.
However, the blocking artifacts of the segmentation results show that it is
preferable to combine both class and position information so as to achieve
smoother and more accurate boundary estimation.
In Chapter 5, based on the same MFT-MMRF framework, a boundary
process is proposed to refine the segmentation result of the region process
proposed in Chapter 4. At each resolution, all the image blocks on either
sides of the preliminary boundary detected in the region process are treated
as potential boundary-containing blocks (PBCB's). The orientation and the
centroid of the boundary-segment contained in each PBCB are calculated.
The sequence of PBCB's are then modelled as a MRF and the interaction
energy between each pair of neighbouring blocks is defined as a function of
the 'distance' D between the centroids of the two boundary segments. During
the stochastic relaxation process boundary/non-boundary labels are assigned
to the PBCB's. Once the algorithm converges, the centroids of the identified
true boundary blocks are connected to form the refined boundary which is
propagated down to the next resolution for further refinement
Over-the-counter drugs used by adolescents in Germany: How much do adolescents spend and what for?
No full textLaser capabilities of CuBr mixture excited by RF discharge
No full textOur investigations demonstrated that utilizing copper bromide (CuBr) mixture as
a source of Cu atoms in a RF-excited discharge can be a promising alternative to
the Cu sputtered system, when the development of Cu ion gas laser is considered.
Both spectroscopic and laser investigations showed that the
threshold input
power for lasing was reduced about 5 times using the CuBr-based system instead
of
the Cu-sputtered system. Pulsed and CW laser oscillation on Cu+ transitions
in the near IR spectral region was obtained in RF-excited He-CuBr discharge
operated at 13.56 MHz and 27.12 MHz. At input RF power of 800 W, a laser output
power of 10 mW at the 780.8 nm Cu ion laser line was achieved. An increase of
laser output power by a factor of two, as well as better Cu vapour axial
distribution and better discharge stability, was attained when DC discharge was
superimposed on the RF discharge. Laser gain on 11 UV Cu ion lines was observed
in RF-excited Ne-CuBr discharge. basing on the obtained results, we consider the
CuBr laser system excited by RF discharge capable of generating UV laser
radiation at relatively low input power
Over-the-counter drugs used by adolescents in Germany: How much do adolescents spend and what for?
No full textA machine vision system for automated non-invasive assessment of cell viability via dark field microscopy, wavelet feature selection and classification
No full textWei N, Flaschel E, Friehs K, Nattkemper TW. A machine vision system for automated non-invasive assessment of cell viability via dark field microscopy, wavelet feature selection and classification. BMC Bioinformatics. 2008;9(1):449.Background: Cell viability is one of the basic properties indicating the physiological state of the cell, thus, it has long been one of the major considerations in biotechnological applications. Conventional methods for extracting information about cell viability usually need reagents to be applied on the targeted cells. These reagent-based techniques are reliable and versatile, however, some of them might be invasive and even toxic to the target cells. In support of automated noninvasive assessment of cell viability, a machine vision system has been developed. Results: This system is based on supervised learning technique. It learns from images of certain kinds of cell populations and trains some classifiers. These trained classifiers are then employed to evaluate the images of given cell populations obtained via dark field microscopy. Wavelet decomposition is performed on the cell images. Energy and entropy are computed for each wavelet subimage as features. A feature selection algorithm is implemented to achieve better performance. Correlation between the results from the machine vision system and commonly accepted gold standards becomes stronger if wavelet features are utilized. The best performance is achieved with a selected subset of wavelet features. Conclusion: The machine vision system based on dark field microscopy in conjugation with supervised machine learning and wavelet feature selection automates the cell viability assessment, and yields comparable results to commonly accepted methods. Wavelet features are found to be suitable to describe the discriminative properties of the live and dead cells in viability classification. According to the analysis, live cells exhibit morphologically more details and are intracellularly more organized than dead ones, which display more homogeneous and diffuse gray values throughout the cells. Feature selection increases the system's performance. The reason lies in the fact that feature selection plays a role of excluding redundant or misleading information that may be contained in the raw data, and leads to better results
