Search results for "Transform"
showing 10 items of 3975 documents
A Hybrid Frequency-Space Approach for Shape Measurement by Shadow Moiré Technique with Carrier Fringe Pattern
2006
In this paper, a novel methodology to process fringe pattern is presented. The core of the signal processing technique is the use of the direction information, a modulo 2pi quantity that locally informs about the direction along which fringes grow with maximum rate. By using this information, it was possible to perform adaptive, direction- and orientation-based operations on fringe images in order to remove unwanted effects, to enhance the contrast and to extract the phase information encoded. The method has been applied on shadow moire interferograms with carrier fringes in order to measure the surface of small objects. The developed algorithm allows to process fringes whose phase informat…
Space–bandwidth product of optical signals and systems
1996
The space–bandwidth product (SW) is fundamental for judging the performance of an optical system. Often the SW of a system is defined only as a pure number that counts the degrees of freedom of the system. We claim that a quasi-geometrical representation of the SW in the Wigner domain is more useful. We also represent the input signal as a SW in the Wigner domain. For perfect signal processing it is necessary that the system SW fully embrace the signal SW.
A Direction/Orientation-Based Method for Shape Measurement by Shadow MoirÉ
2008
In this paper, a methodology to process fringe patterns is presented. The core of the signal processing technique is the use of the direction information, which is a modulo quantity that locally indicates the direction along which fringes grow at a maximum rate. By using this information, it was possible to perform adaptive and direction/orientation-based operations on fringe images to remove unwanted effects (mainly distortions at the image borders), to enhance the contrast, and to extract the phase information encoded. The method has been applied on shadow-moire interferograms with carrier fringes in order to measure the surface of small objects. The developed algorithm allows processing …
Pikosekunžu precizitātes laika intervālu mērīšanas un analīzes skaitlisko metožu izstrāde satelītu lāzerlokācijā pielietojumam
2002
Lāzerlokācijas metožu izmantošana zinātniskās programmās, kuras saistītas ar globālās ģeocentrisko koordinātu sistēmas definēšanu, Zemes rotācijas tekošo parametru noteikšanu, Zemes polu kustības mērījumiem, kontinentu dreifa noteikšanu, iespējamo zemestrīču prognozēšanu, prasa ļoti augstas precizitātes (0.5-2 cm) satelītu attālumu mērījumu rezultātus. Eksistējošie lāzeru tālmēri, daudzos gadījumos, nepilnīgi atbilst šīm prasībām, dodot precizitāti ap 4 cm. Risinot minētos lokācijas uzdevumus, liela loma ir laika intervālu analizatoru augstai izšķiršanas spējai. Satelītu lokācijā laika intervāla atsevišķa mērījuma vidējā kvadrātiskā kļūda nedrīkst pārsniegt dažus desmitus pikosekunžu, pie i…
Boron doping of silicon rich carbides: Electrical properties
2013
Boron doped multilayers based on silicon carbide/silicon rich carbide, aimed at the formation of silicon nanodots for photovoltaic applications, are studied. X-ray diffraction confirms the formation of crystallized Si and 3C-SiC nanodomains. Fourier Transform Infrared spectroscopy indicates the occurrence of remarkable interdiffusion between adjacent layers. However, the investigated material retains memory of the initial dopant distribution. Electrical measurements suggest the presence of an unintentional dopant impurity in the intrinsic SiC matrix. The overall volume concentration of nanodots is determined by optical simulation and is shown not to contribute to lateral conduction. Remarka…
Neural cell pattern formation on glass and oxidized silicon surfaces modified with poly(N-isopropylacrylamide)
1996
Control over the adsorption of proteins and over the adsorption and spatial orientation of mammalian cells onto surfaces has been achieved by modification of glass and other silicon oxide substrates with poly(N-isopropylacrylamide) (PNIPAM). The functionalization of the substrates was achieved either by a polymer-analogous reaction of aminosilanes with reactive N-(isopropylacrylamide) (NIPAM)-copolymers and by copolymerization of NIPAM with surface-bound methacrylsilane. The obtained coatings were characterized by FT-1R, ellipsometry, and surface plasmon resonance measurements. The adsorption of two proteins-fibrinogen and ribonuclease A-on these surfaces was studied in situ by real time su…
Cs2 molekulas A~b kompleksa augstas izšķirtspējas spektroskopiskie pētījumi un elektroniskās struktūras analīze
2019
Šajā maģistra darbā veikts Cs2 molekulas 〖A^1∑〗_u^+ un 〖b 〗^3 Π_u stāvokļu kompleksa elektroniskās-svārstību-rotācijas struktūras pētījums pielietojot Furjē transformāciju spektroskopijas un lāzera inducētās fluorescences (LIF) metodes. 〖A^1∑〗_u^+ un 〖b 〗^3 Π_u stāvokļus raksturo spēcīga spin-orbitālā mijiedarbība, kuras rezultātā stāvokļi veido saistītu A~b kompleksu. Cs2 molekulas pētīšanai maģistra darbā pielietota LIF metode, izmantojot dažādas lāzeru sistēmas, kombinācijā ar Furjē transformāciju spektrometru (Bruker IFS-125HR). Eksperimentāli reģistrēti un analizēti Cs2 molekulas spektri pārejās no A~b kompleksa uz pamatstāvokli. Darbā aprakstīts spektru apstrādes process, kura rezultā…
Bioprospective of Sorbus aucuparia leaf extract in development of silver and gold nanocolloids
2010
At the present time the bioprospective field is a dynamic area of research. The rapid biosynthesis of silver and gold nanoparticles without using toxic chemicals is reported here. Sorbus aucuparia is omnipresent in Europe. The aqueous leaves extract of the plant were used as reducing agent for the synthesis of silver and gold nanoparticles from their salt solutions. The synthesized nanoparticles were spherical, triangular and hexagonal in shape with an average size of 16 and 18nm for silver and gold, respectively. Different extract quantities, metal concentrations, temperatures and contact times were investigated to find their effect on nanoparticles synthesis. The resulting silver and gold…
Views selection for SIFT based object modeling and recognition
2016
In this paper we focus on automatically learning object models in the framework of keypoint based object recognition. The proposed method uses a collection of views of the objects to build the model. For each object the collection is composed of N×M views obtained rotating the object around its vertical and horizontal axis. As keypoint based object recognition using a complete set of views is computationally expensive, we focused on the definition of a selection method that creates, for each object, a subset of the initial views that visually summarize the characteristics of the object and should be suited for recognition. We select the views by determining maxima and minima of a function, …
Predicting Next Dialogue Action in Emotionally Loaded Conversation
2021
This paper reports on creating a neural network model for prediction of the next action in a dialogue considering conversation history, i.e. entities, context variables and emotion indicators marking emotionally loaded user utterances. Several experiments were performed to see how the information about emotions affects the accuracy of the model. For the purposes of these experiments, a dataset containing 206 dialogs in Latvian in the transport inquiry domain was created containing both neutral and emotionally loaded utterances. To see if the proposed next dialogue action prediction model architecture is suitable for other languages, the original Latvian utterances were translated into Engli…