Search results for "contrast"
showing 10 items of 1162 documents
High-contrast dark resonances on the D1 line in cesium nanocell: the advantages compared with the other alkali D lines
2015
Electromagnetically induced transparency (EIT) effect in a -system formed by Cs atoms line, enclosed in nanometric-thin cells, is studied both experimentally and theoretically for the first time. T...
Comparative electronmicroscopic studies on the central cardiac organs of cephalopods (Sepia officinalis)
1969
Die Untersuchungen zur Feinstruktur des Herzens von Sepia officinalis zeigen fur die quer- bzw. schraggestreifte Muskulatur dieses Organs einen hohen Differenzierungsgrad auf. 1. Die Sarkomeren werden mit dem Auftreten zweier Filamenttypen wie die quergestreifte Vertebratenmuskulatur in Z-, A- und I-Bande gegliedert, wobei jedoch die Z-Bande aus einzelnen Teilelementen besteht. 2. Die Herzmuskulatur der Cephalopoden verfugt uber Strukturen, die in Analogie zum Vertebratenherzen als Disci intercalares bezeichnet werden. 3. eben einem langs und quer verlaufenden sarkotubularen System wird die Existenz eines mit dem Ausenraum kommunizierenden T-Systems nachgewiesen. Beide Systeme stehen uber M…
High-pass energy-filtered photoemission electron microscopy imaging of dopants in silicon.
2008
Differently doped areas in silicon can show strong electron-optical contrast in dependence on the dopant concentration and surface conditions. Photoemission electron microscopy is a powerful surface-sensitive technique suitable for fast imaging of doping-induced contrast in semiconductors. We report on the observation of Si (100) samples with n- and p-type doped patterns (with the dopant concentration varied from 10(16) to 10(19) cm(-3)) on a p- and n-type substrate (doped to 10(15) cm(-3)), respectively. A high-pass energy filter of the entire image enabled us to obtain spectroscopic information, i.e. quantified photo threshold and related photoyield differences depending on the doping lev…
Laboratory phase‐contrast nanotomography of unstained Bombus terrestris compound eyes
2021
Imaging the visual systems of bumblebees and other pollinating insects may increase understanding of their dependence on specific habitats and how they will be affected by climate change. Current high-resolution imaging methods are either limited to two dimensions (light- and electron microscopy) or have limited access (synchrotron radiation x-ray tomography). For x-ray imaging, heavy metal stains are often used to increase contrast. Here, we present micron-resolution imaging of compound eyes of buff-tailed bumblebees (Bombus terrestris) using a table-top x-ray nanotomography (nano-CT) system. By propagation-based phase-contrast imaging, the use of stains was avoided and the microanatomy co…
ICDAR 2021 Competition on Historical Document Classification
2021
International audience; This competition investigated the performance of historical document classification. The analysis of historical documents is a difficult challenge commonly solved by trained humanists. We provided three different classification tasks, which can be solved individually or jointly: font group/script type, location, date. The document images are provided by several institutions and are taken from handwritten and printed books as well as from charters. In contrast to previous competitions, all participants relied upon Deep Learning based approaches. Nevertheless, we saw a great performance variety of the different submitted systems. The easiest task seemed to be font grou…
Optical-sectioning microscopy by patterned illumination
2010
We propose a very simple method for the flexible production of 1D structured illumination for high resolution 3D microscopy. Specifically, we propose the insertion of a Fresnel biprism after a monochromatic point source for producing a pair of twin, fully coherent, virtual point sources. The resulting interference fringes are projected into the 3D sample and, by simply varying the distance between the biprism and the point source, one can tune the period of the fringes, while keeping their contrast, in a very versatile and efficient way.
Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance.
2020
Journal of nanobiotechnology 18, 22 (2020). doi:10.1186/s12951-020-0580-1
Optical contrast of 2D InSe on SiO2/Si and transparent substrates using bandpass filters
2017
The particular optical and electronic properties recently reported for 2D InSe depict this 2D material as being very versatile for future electronic and optoelectronic devices with tunable and optimized functionalities. For its fundamental study and the development of practical applications, rapid and accurate identification methods of atomically thin InSe are essential. Here, we demonstrate an enhancement of the optical contrast between InSe nanosheets and the underlying SiO2/Si substrate by illuminating with a 40 nm wide bandpass filter centered at 500 nm. Moreover, we study the optical contrast of 2D InSe on transparent substrates. Our results suggest that a good optical contrast is achi…
Quantitative comparison of new image processing methods for volumetric analysis of left ventricular contrast echocardiograms
2003
An effort has been made to develop image processing methods which allow a definite and precise tracking of the borderline of the ventricle in two-dimensional echocardiograms. Experience is reported with two new methods, which are based on the gray-level rise (GL) and the signal-to-noise ratio (SNR) in combined heart-phase-triggered image series. A quantitative comparison of these time-series methods is presented with respect to the interpretation of a single native image (noncontrast image), a single contrast-material image, the corresponding subtraction image, and the corresponding color superposition image. The comparison is based on the calculation of the ejection fraction using the abov…
Dual-beam confocal light-sheet microscopy via flexible acousto-optic deflector
2019
Confocal detection in digital scanned laser light-sheet fluorescence microscopy (DSLM) has been established as a gold standard method to improve image quality. The selective line detection of a complementary metal-oxide-semiconductor camera (CMOS) working in rolling shutter mode allows the rejection of out-of-focus and scattered light, thus reducing background signal during image formation. Most modern CMOS have two rolling shutters, but usually only a single illuminating beam is used, halving the maximum obtainable frame rate. We report on the capability to recover the full image acquisition rate via dual confocal DSLM by using an acoustooptic deflector. Such a simple solution enables us t…