Search results for "Deconvolution"
showing 10 items of 82 documents
Study of As and Tl high-frequency electrodeless lamps for Zeeman absorption spectroscopy
2020
High-frequency electrodeless light sources are known as bright radiators with the line spectrum, characterized by high intensities and narrow line shapes. The lamp balloons are mostly made of quartz and filled with a metal and buffer gas. These light sources must be optimized for each application in accordance with the specific requirements of radiation quality, lifetime, and stability. This work is devoted to the diagnostic of high-frequency electrodeless light sources for their use in high precision atomic absorption analyzers and other applications like disinfection. The spectral line intensities and profiles were studied in discharges with arsenic and thallium fillings. Special attentio…
A general framework for a class of non-linear approximations with applications to image restoration
2018
Este artículo se encuentra disponible en la página web de la revista en la siguiente URL: https://www.sciencedirect.com/science/article/abs/pii/S0377042717301188 Este es el pre-print del siguiente artículo: Candela, V., Falcó, A. & Romero, PD. (2018). A general framework for a class of non-linear approximations with applications to image restoration. Journal of Computational and Applied Mathematics, vol. 330 (mar.), pp. 982-994, que se ha publicado de forma definitiva en https://doi.org/10.1016/j.cam.2017.03.008 This is the pre-peer reviewed version of the following article: Candela, V., Falcó, A. & Romero, PD. (2018). A general framework for a class of non-linear approximations with applic…
Retrieving leaf area index from multi-angular airborne data
2009
This work is aimed to demonstrate the feasibility of a methodology for retrieving bio-geophysical variables whilst at the same time fully accounting for additional information on directional anisotropy. A model-based approach has been developed to deconvolve the angular reflectance into single landcovers reflectances, attempting to solve the inconsistencies of 1D models and linear mixture approaches. The model combines the geometric optics of large scale canopy structure with principles of radiative transfer for volume scattering within individual crowns. The reliability of the model approach to retrieve LAI has been demonstrated using data from DAISEX- 99 campaign at Barrax, Spain. Airborn…
What about computational super-resolution in fluorescence Fourier light field microscopy?
2020
Recently, Fourier light field microscopy was proposed to overcome the limitations in conventional light field microscopy by placing a micro-lens array at the aperture stop of the microscope objective instead of the image plane. In this way, a collection of orthographic views from different perspectives are directly captured. When inspecting fluorescent samples, the sensitivity and noise of the sensors are a major concern and large sensor pixels are required to cope with low-light conditions, which implies under-sampling issues. In this context, we analyze the sampling patterns in Fourier light field microscopy to understand to what extent computational super-resolution can be triggered duri…
Fourier-domain lightfield microscopy: a new paradigm in 3D microscopy
2020
Recently, integral (also known as lightfield or plenoptic) imaging concept has been applied successfully to microscopy. The main advantage of lightfield microscopy when compared with conventional 3D imaging techniques is that it offers the possibility of capturing the 3D information of the sample after a single shot. However, integral microscopy is now facing many challenges, like improving the resolution and depth of field of the reconstructed specimens or the development and optimization of specially-adapted reconstruction algorithms. This contribution is devoted to review a new paradigm in lightfield microscopy, namely, the Fourier-domain integral microscope (FiMic), that improves the ca…
Reduction of spherical-aberration impact in microscopy by wavefront coding
2009
In modern high-NA optical scanning instruments, like scanning microscopes, the refractive-index mismatch between the sample and the immersion medium introduces a significant amount of spherical aberration when imaging deep inside the specimen, spreading out the impulse response. Since such aberration depends on the focalization depth, it is not possible to achieve a static global compensation for the whole 3D sample in scanning microscopy. Therefore a depth-variant impulse response is generated. Consequently, the design of pupil elements that increase the tolerance to this aberration is of great interest. In this paper we report a hybrid technique that provides a focal spot that remains alm…
Combinatorial approaches: A new tool to search for highly structured β-hairpin peptides
2002
Here we present a combinatorial approach to evolve a stable β-hairpin fold in a linear peptide. Starting with a de novo -designed linear peptide that shows a β-hairpin structure population of around 30%, we selected four positions to build up a combinatorial library of 20 4 sequences. Deconvolution of the library using circular dichroism reduced such a sequence complexity to 36 defined sequences. Circular dichroism and NMR of these peptides resulted in the identification of two linear 14-aa-long peptides that in plain buffered solutions showed a percentage of β-hairpin structure higher than 70%. Our results show how combinatorial approaches can be used to obtain highly structured peptide s…
Capillary electrophoresis enhanced by automatic two-way background correction using cubic smoothing splines and multivariate data analysis applied to…
2005
Mixtures of the surfactant classes coconut diethanolamide, cocamido propyl betaine and alkylbenzene sulfonate were separated by capillary electrophoresis in several media containing organic solvents and anionic solvophobic agents. Good resolution between both the surfactant classes and the homologues within the classes was achieved in a BGE containing 80 mM borate buffer of pH 8.5, 20% n-propanol and 40 mM sodium deoxycholate. Full resolution, assistance in peak assignment to the classes (including the recognition of solutes not belonging to the classes), and improvement of the signal-to-noise ratio was achieved by multivariate data analysis of the time-wavelength electropherograms. Cubic s…
Towards unsupervised analysis of second-order chromatographic data: automated selection of number of components in multivariate curve-resolution meth…
2007
A method to apply multivariate curve-resolution unattendedly is presented. The algorithm is suitable to perform deconvolution of two-way data (e.g. retrieving the individual elution profiles and spectra of co-eluting compounds from signals obtained from a chromatograph equipped with multiple-channel detection: LC-DAD or GC-MS). The method is especially adequate to achieve the advantages of deconvolution approaches when huge amounts of data are present and manual application of multivariate techniques is too time-consuming. The philosophy of the algorithm is to mimic the reactions of an expert user when applying the orthogonal projection approach--multivariate curve-resolution techniques. Ba…
Some experimental issues of AFM tip blind estimation. The effect of noise and resolution
2006
The convolution of tip shape on sample topography can introduce significant inaccuracy in an AFM image, when the tip radius is comparable to the typical dimension of the sample features to be observed. The blind estimation method allows one to obtain information on the AFM tip through an unknown characterizer sample and thus to perform the deconvolution of the tip shape from an image. When applying the blind estimation method to determine the AFM tip shape, some apparently trivial issues relating to the experimental operating parameters must be taken into account. In this paper, the effects of the operating parameters, e.g., sampling intervals (resolution) and instrumental noise, have been …