Search results for "image resolution"
showing 10 items of 377 documents
In-situ high spatial resolution LA-MC-ICPMS 230Th/U dating enables detection of small-scale age inversions in speleothems
2017
Abstract We present an in-situ method for Th and U isotope measurements by laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) to determine possible age inversions of stalagmites, using a 213 nm Nd:YAG laser connected to an MC-ICPMS. Due to the low ion beam intensity of 230 Th (20–120 counts per second, cps), we carefully optimized the operating parameters to get highest possible ion beam intensities, i.e., laser fluence (25 J cm −2 ), spot size (110 μm), pulse repetition rate (20 Hz), scan speed (4 μm s −1 ), integration time (1000 s), and He and Ar gas flow (∼0.9 L min −1 and ∼0.6 L min −1 respectively). A precision (2 relative standard error, 2RSE) o…
X-ray microtomography and laser ablation in the analysis of ink distribution in coated paper
2015
A novel method was developed for studying the ink-paper interface and the structural variations of a deposited layer of ink. Combining high-resolution x-ray tomography with laser ablation, the depth profile of ink (toner), i.e., its varying thickness, could be determined in a paper substrate. X-ray tomography was used to produce the 3D structure of paper with about 1 μm spatial resolution. Laser ablation combined with optical imaging was used to produce the 3D structure of the printed layer of ink on top of that paper with about 70 nm depth resolution. Ablation depth was calibrated with an optical profilometer. It can be concluded that a toner layer on a light-weight-coated paper substrate …
Monthly Land Surface Temperature maps over European Zone using Advanced Along Track Scanning Radiometer data for 2007
2009
Land Surface Temperature (LST) monthly maps are necessary in climatic studies and remote sensing is a key tool used to obtain these maps. For this reason, we used the LST product of AATSR on board Envisat. This product uses a split-window algorithm which depends on vertical column water vapour content (W) and viewing angle. The algorithm proposed in Galve et al. [1] was also used, which is based on the Coll and Caselles [2] split-window model and depends explicitly on the emissivity and W. This algorithm was tested with concurrent ground measurements in the Valencia validation site, yielding an error of + 0.5 K. With both algorithms we perform LST maps over Europe with a spatial resolution …
The FLuorescence EXplorer Mission Concept-ESA's Earth Explorer 8
2017
In November 2015, the FLuorescence EXplorer (FLEX) was selected as the eighth Earth Explorer mission of the European Space Agency. The tandem mission concept will provide measurements at a spectral and spatial resolution enabling the retrieval and interpretation of the full chlorophyll fluorescence spectrum emitted by the terrestrial vegetation. This paper provides a mission concept overview of the scientific goals, the key objectives related to fluorescence, and the requirements guaranteeing the fitness for purpose of the resulting scientific data set. We present the mission design at the time of selection, i.e., at the end of project phase Phase A/B1, as developed by two independent indus…
Hierarchical Parallelization of an H.264/AVC Video Encoder
2006
Last generation video encoding standards increase computing demands in order to reach the limits on compression efficiency. This is particularly the case of H.264/AVC specification that is gaining interest in industry. We are interested in applying parallel processing to H.264 encoders in order to fulfill the computation requirements imposed by stressing applications like video on demand, videoconference, live broadcast, etc. Given a delivered video quality and bit rate, the main complexity parameters are image resolution, frame rate and latency. These parameters can still be pushed forward in such a way that special purpose hardware solutions are not available. Parallel processing based on…
Simulation of laser generated ultrasound with application to defect detection
2008
Laser generated ultrasound holds substantial promise for use as a tool for defect detection in remote inspection thanks to its ability to produce frequencies in the MHz range, enabling fine spatial resolution of defects. Despite the potential impact of laser generated ultrasound in many areas of science and industry, robust tools for studying the phenomenon are lacking and thus limit the design and optimization of non-destructive testing and evaluation techniques. The laser generated ultrasound propagation in complex structures is an intricate phenomenon and is extremely hard to analyze. Only simple geometries can be studied analytically. Numerical techniques found in the literature have pr…
Analysis of the depth of field of integral imaging displays based on wave optics.
2013
In this paper, we analyze the depth of field (DOF) of integral imaging displays based on wave optics. With considering the diffraction effect, we analyze the intensity distribution of light with multiple micro-lenses and derive a DOF calculation formula for integral imaging display system. We study the variations of DOF values with different system parameters. Experimental results are provided to verify the accuracy of the theoretical analysis. The analyses and experimental results presented in this paper could be beneficial for better understanding and designing of integral imaging displays.
Spatio-temporal Characteristics of THz Emission at the Subwavelength Scale via Optical Rectification
2011
Highly localized THz emission via optical rectification in thin nonlinear crystals is a promising method for subwavelength microscopy. We present here the peculiar THz spatio-temporal characteristics induced by the non-paraxial generation regime.
Ultrathin high-index metasurfaces for shaping focused beams
2015
The volume size of a converging wave, which plays a relevant role in image resolution, is governed by the wavelength of the radiation and the numerical aperture (NA) of the wavefront. We designed an ultrathin (λ/8 width) curved metasurface that is able to transform a focused field into a high-NA optical architecture, thus boosting the transverse and (mainly) on-axis resolution. The elements of the metasurface are metal-insulator subwavelength gratings exhibiting extreme anisotropy with ultrahigh index of refraction for TM polarization. Our results can be applied to nanolithography and optical microscopy. Spanish Ministry of Economy and Competitiveness (MEC) (TEC2013-50416-EXP).
Hyperspectral imager calibration using ceramic color tiles (Conference Presentation)
2019
Sets of chromatic and neutral ceramic tiles are widely used as measurement standards for reflectance factors in color applications. The usual instrument for color measurements is a spectrophotometer that measures the tiles using either a 0:45 or 45:0 illumination and viewing geometry, or with an integrating sphere in order to measure the reflectance factor in either specular excluded or specular included conditions. Having the corresponding measurements of the tile set from a calibrated instrument, systematic errors in the instrument under study can be diagnosed and corrected using a model of the errors and fitting it to the difference in measurements. One such is the Berns-Petersen model, …