Search results for "optical"
showing 10 items of 7671 documents
Nonlinear radial-harmonic correlation using binary decomposition for scale-invariant pattern recognition
2003
We introduce a new scale-invariant pattern-recognition method that uses nonlinear correlation. We applied several common linear correlations to images decomposed into disjoint binary images, which is very discriminant even when the target is embedded in strong noise. We combine our sliced orthogonal nonlinear generalized correlation method and the radial-harmonic expansion in order to achieve scale-invariant pattern recognition. The information from a radial harmonic for each binary slice of the reference object is combined with binary slices of the target. The method avoids the time-consuming process of finding expansion centers for the radial harmonics. The stability of the correlation pe…
Improved rotation invariant pattern recognition using circular harmonics of binary gray level slices
2000
We introduce a new rotation invariant pattern recognition method based on nonlinear correlation. The images are decomposed into disjoint binary slices and then correlated using the common linear correlation. This operation is very discriminant even when the target is embedded in strong noise. We extend our sliced orthogonal nonlinear generalized correlation method to rotation invariant pattern recognition by combining the information of a circular harmonic (CH) of each binary slice of the reference object with binary slices of the target. In addition to improved discrimination capability, the method avoids the time-consuming process of finding proper centers for the CHs. Results are present…
Detecting motion independent of the camera movement through a log-polar differential approach
1997
This paper is concerned with a differential motion detection technique in log-polar coordinates which allows object motion tracking independently of the camera ego-motion when camera focus is along the movement direction. The method does not use any explicit estimation of the motion field, which can be calculated afterwards at the moving points. The method, previously formulated in Cartesian coordinates, uses the log-polar coordinates, which allows the isolation of the object movement from the image displacement due to certain camera motions. Experimental results on a sequence of real images are included, in which a moving object is detected and optical flow is calculated in log-polar coord…
Raman and optical reflection spectra of germanate and silicate glasses
2005
Abstract Germanate and phosphosilicate glasses made in oxygen surplus conditions were studied by Raman and optical reflection methods. We found that the optical reflection spectra of the germanate glasses are quite similar to the one those of a GeO 2 crystal with the α-quartz structure. The reflection of phosphosilicate glasses is very close to silica glass-related spectra. Hence, the determining influence of the tetrahedral structure on reflection spectra is revealed. The Raman spectra of germanate samples are similar to those reported the one known in the literature. Octahedral entities, namely bands similar to stishovite vibration modes, were difficult to detect in phosphosilicate glasse…
Nano-lithography by electron exposure using an Atomic Force Microscope
1999
Abstract We have used a conductive Atomic Force Microscope (AFM) tip to expose a very thin resist film. An exposing current of low energy electrons was induced from the tip to the substrate by applying a small bias voltage. Uniform resist films as thin as 10 nm were fabricated using the Langmuir–Blodgett technique. To orient the defined pattern and to make electrical connections a special larger scale alignment structure was first defined by conventional electron beam lithography, either directly in the Langmuir–Blodgett resist film or in a separate first lift-off process with a thicker resist. The results from the one resist process gave conducting 50 nm lines with a 60 A thick vacuum depo…
ZnO/CdTe/CuSCN, a promising heterostructure to act as inorganic eta-solar cell
2005
Abstract The ZnO/CdTe/CuSCN heterostructure was analyzed as a candidate to act as an inorganic eta -solar cell. A ZnO film consisting of single crystal nanocolumns was electrodeposited on a transparent conducting substrate which acts as n-type material. As absorber material we used CdTe, which was deposited on the ZnO columnar film by Metal Organic Chemical Vapor Deposition. In order to complete the eta -solar cell we deposited a CuSCN layer by chemical solution deposition. A conformal and uniform CdTe coverage of the ZnO columns was achieved, producing a very efficient light trapping effect. The effective absorption (∼87%) and effective reflectance (∼10%) of the complete heterostructure in…
Co-adsorption processes, kinetics and quantum mechanical modelling of nanofilm semiconductor gas sensors
2010
A quantum mechanical model of co-adsorption on semiconductor surfaces is developed and successfully adopted towards exposure to several gases. It is related to nanofilms and thus allows the application of electric fields altering the electronic surface properties of adsorption centres (electro-adsorptive effect, EAE). The model is matched against experimental data with O 2 , NO 2 and CO measurements under the hypothesis of no direct interaction among the species. However the sequence of adsorption plays an important role where the adsorption of one gas species is opening up other sites that are filled by another sort of impinging molecules. Quantum mechanical modelling of co-adsorption: (a)…
Material quality characterization of CdZnTe substrates for HgCdTe epitaxy
2006
Cd1−xZnxTe (CZT) substrates were studied to investigate their bulk and surface properties. Imperfections in CZT substrates affect the quality of Hg1−xCdxTe (MCT) epilayers deposited on them and play a role in limiting the performance of infrared (IR) focal plane arrays. CZT wafers were studied to investigate their bulk and surface properties. Transmission and surface x-ray diffraction techniques, utilizing both a conventional closed-tube x-ray source as well as a synchrotron radiation source, and IR transmission micro-spectroscopy, were used for bulk and surface investigation. Synchrotron radiation offers the capability to combine good spatial resolution and shorter exposure times than conv…
Novel voltage-controlled conditioning circuit applied to the ISFETs temporary drift and thermal dependency
2003
This paper describes a novel conditioning circuit applied to ion-sensitive field-effect transistors/membrane-ion-sensitive field-effect transistors (ISFETs/MEMFETs) sensors. The novel conditioning circuit allows the sensor polarization with the needed either voltage or current required in each application, thanks to two completely independent voltage-controlled blocks (current and voltage blocks). The control of the voltage block is the most critical point in our design because the voltage block maintains the sensor feedback stable, avoiding the thermal and temporary drifts of the sensor feedback.
Measurement of haemodynamics of exercising and non-exercising vastus lateralis muscle with hybrid diffuse optics
2016
We present simultaneous diffuse correlation spectroscopy (DCS) and time resolved spectroscopy (TR NIRS) measurements on exercising and non-exercising vastus lateralis muscle. We discuss the results at two different exercise levels.