Search PubMed⌕ Search

PubMed · 10828202

The multidimensional filter diagonalization method.

Abstract

The theory and numerical aspects of the recently developed multidimensional version of the filter diagonalization method (FDM) are described in detail. FDM can construct various "ersatz" or "hybrid" spectra from multidimensional time signals. Spectral resolution is not limited by the time-frequency uncertainty principle in each separate frequency dimension, but rather by the total joint information content of the signal, i.e., N(total) = N(1) x N(2) x vertical ellipsis x N(D), where some of the interferometric dimensions do not have to be represented by more than a few (e.g., two) time increments. It is shown that FDM can be used to compute various reduced-dimensionality projections of a high-dimensional spectrum directly, i.e., avoiding construction of the latter. A subsequent paper (J. Magn. Reson. 144, 357-366 (2000)) is concerned with applications of the method to 2D, 3D, and 4D NMR experiments.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

V A Mandelshtam. 2000. The multidimensional filter diagonalization method.. https://doi.org/10.1006/jmre.2000.2023

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

Two-photon autofluorescence microscopy and spectroscopy of Antarctic fungus: new approach for studying effects of UV-B irradiation.

We combined two-photon fluorescence microscopy and spectroscopy to provide functional images of UV-B (280-315 nm) induced stress on an Antarctic fungus. Two-photon excitation microscopy was used to characterize the distribution of autofluorescence inside the spore and the hyphae of the fungus. The imaging analysis clearly shows that the autofluorescence response of spores is higher than that of hyphae. The imaging analysis at different depths shows that, strikingly enough, the spore autofluorescence originates from the cell wall and membrane fluorophores. The spectroscopic results show moreover that the fluorescence spectra of spores are redshifted upon UV-B irradiation. Tentative identification of the chromophores involved in the autofluorescence response and their biological relevance are also discussed on the basis of a previous steady-state fluorescence spectroscopic study performed on both whole spore suspension and organic-soluble extracts.

Image Processing, Computer-Assisted↗

Omega-space adaptive acquisition technique for magnetic resonance imaging from projections.

An omega-space adaptive acquisition technique for MRI from projections is presented. It is based on the evaluation of the information content of a set composed of four initial projections, measured at angles 0 degrees, 45 degrees, 90 degrees, and 135 degrees, followed by the selection of new angles where the information content is maximum. An entropy function is defined on the power spectrum of the projections that is useful for evaluating the information content of each projection. The method makes it possible to reduce the total acquisition time with little degradation of the reconstructed image and it adapts to the arbitrary shape of the sample. For this reason, it can be particularly useful in those applications where acquisition from projections is strongly recommended to save acquisition time, such as functional MRI, imaging of species having very short T(2), or angiography. The method has been tested both on simulated data and on experimental data collected by a commercial MRI apparatus. The method has also been compared to the regular acquisition method, that is, the standard acquisition method in MRI from projections.

Image Processing, Computer-Assisted↗

Ultrasound grayscale image compression with JPEG and wavelet techniques.

The purpose of the study was to evaluate the effects of lossy compression on grayscale ultrasound images to determine how much compression can be applied while still maintaining images that are acceptable for diagnostic purposes. The study considered how the acquisition technique (video frame-grabber versus directly acquired in digital form) influences how much compression can be applied. For directly acquired digital images, the study considered how text (that is burned into the image) affects the compressibility of the image. The lossy compression techniques that were considered include JPEG and a Wavelet algorithm using set partitioning in hierarchical trees (SPIHT).

Image Processing, Computer-Assisted↗