The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform

T.g. Strand - One of the best experts on this subject based on the ideXlab platform.

  • A Commercial Scanner Applied as a Microdensitometer for Gas Electron-Diffraction Photographic Plates
    Journal of Applied Crystallography, 1996
    Co-Authors: S. Gundersen, T.g. Strand
    Abstract:

    The present state of the hardware and software of our Joyce-Loebl MK III CS 1970 microdensitometer is reported. The modifications to the existing software necessary for it to be applicable to the data from an Agfa Arcus II commercial scanner are described. The accuracies of the two instruments are compared by the measurement and analysis of photographic plates for two data sets of the short nozzle-to-plate distance of benzene. For about 30000 measured points on both devices, the two instruments give practically the same accuracy, except for very light plates where the Joyce-Loebl results seem to be the best ones. The ra(C–C) distance obtained from the scanner data is systematically elongated by about 0.5%. Acceptable agreement of the root-mean-square vibrational amplitudes from the two instruments is obtained. A sixfold increase in the number of points applied from the scanner does not improve the agreement very much. The conclusion is that the scanner, in connection with the applied software, can be used as a microdensitometer for gas electron-diffraction plates.

S. Gundersen - One of the best experts on this subject based on the ideXlab platform.

  • A Commercial Scanner Applied as a Microdensitometer for Gas Electron-Diffraction Photographic Plates
    Journal of Applied Crystallography, 1996
    Co-Authors: S. Gundersen, T.g. Strand
    Abstract:

    The present state of the hardware and software of our Joyce-Loebl MK III CS 1970 microdensitometer is reported. The modifications to the existing software necessary for it to be applicable to the data from an Agfa Arcus II commercial scanner are described. The accuracies of the two instruments are compared by the measurement and analysis of photographic plates for two data sets of the short nozzle-to-plate distance of benzene. For about 30000 measured points on both devices, the two instruments give practically the same accuracy, except for very light plates where the Joyce-Loebl results seem to be the best ones. The ra(C–C) distance obtained from the scanner data is systematically elongated by about 0.5%. Acceptable agreement of the root-mean-square vibrational amplitudes from the two instruments is obtained. A sixfold increase in the number of points applied from the scanner does not improve the agreement very much. The conclusion is that the scanner, in connection with the applied software, can be used as a microdensitometer for gas electron-diffraction plates.

Buhr E. - One of the best experts on this subject based on the ideXlab platform.

  • Assessment of radiographic screen-film systems: a comparison between the use of a microdensitometer and a drum film digitiser
    2017
    Co-Authors: Verdun F. R., Pachoud M., Bergmann D., Buhr E.
    Abstract:

    A high-end drum film digitiser (Tango, Germany) and a calibrated linear microdensitometer developed by PTB were used to assess the modulation transfer function (MTF) and the noise power spectra (NPS) of 3 mammographic screen film systems at optical density levels of 0.8, 1.5 and 2.5. The use of a drum scanner to assess MTF and NPS data appears to be adequate but requires an appropriate characterisation of the scanner to verify its internal noise level and its MTF. It is further necessary to calibrate the scanner output in terms of visual diffuse optical densities. Processing of two-dimensional digital data of grating images need to be more strictly defined for accurate MTF measurements of screen-film systems. Nevertheless, even now it seems to be feasible to use commercially available high-end and well calibrated scanners to assess screen film systems. This is especially important for quality assurance purposes because important parameters of screen film systems such like MTF and NPS can now be determined without using sophisticated Microdensitometers which are not commercially availabl

E. Buhr - One of the best experts on this subject based on the ideXlab platform.

  • Assessment of radiographic screen-film systems: a comparison between the use of a microdensitometer and a drum film digitiser.
    Radiation protection dosimetry, 2005
    Co-Authors: Francis R. Verdun, M. Pachoud, D. Bergmann, E. Buhr
    Abstract:

    A high-end drum film digitiser (Tango, Germany) and a calibrated linear microdensitometer developed by PTB were used to assess the modulation transfer function (MTF) and the noise power spectra (NPS) of 3 mammographic screen film systems at optical density levels of 0.8, 1.5 and 2.5. The use of a drum scanner to assess MTF and NPS data appears to be adequate but requires an appropriate characterisation of the scanner to verify its internal noise level and its MTF. It is further necessary to calibrate the scanner output in terms of visual diffuse optical densities. Processing of two-dimensional digital data of grating images need to be more strictly defined for accurate MTF measurements of screen-film systems. Nevertheless, even now it seems to be feasible to use commercially available high-end and well calibrated scanners to assess screen film systems. This is especially important for quality assurance purposes because important parameters of screen film systems such like MTF and NPS can now be determined without using sophisticated Microdensitometers which are not commercially available.

I. Platais - One of the best experts on this subject based on the ideXlab platform.

  • Astrometry with a PDS microdensitometer using cubic splines
    Astronomy and Astrophysics, 1991
    Co-Authors: I. Platais
    Abstract:

    For digital image centering, the cubic spline technique has been applied to marginal distributions of PDS measured density arrays. This centering algorithm provides accuracies similar to that of a symmetric Gaussian. For faint stars, spline fitting is more accurate and stable than the Gaussian one. Spline fitting is also recommended for nonstellar object (comets, galaxies, etc.) astrometry. The optimal use of a PDS microdensitometer is discussed as well