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Image
Correlation Size Distribution DNA Strand Lengths Quasicrystal Symmetry Straighten Curv Object Display Karyotype Nanotube Non-Linearity Mineral Phase Analysis
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Calculates the
length of strands of DNA molecules in SFM images. This procedure uses
the Analyze Particles routine
with thresholds calculated from the values entered in the dialog box.
If appropriate, the image is first processed using the Curvature procedure. The image
is then thresholded at the 'background' level entered (usually less
than 50%) as a compromise between suppressing background features and
fragmenting strands. The image is then smoothed (with a 5 x 5 Gaussian
kernel) and thresholded again at the 'analyse' level entered (usually
less than 50%) to rejoin fragments of strands that were fragmented by
the first thresholding. After the particle analysis has been carried
out, the aspect ratio of each particle is calculated and particles with
values below the minimum value entered are rejected. Press the option
key to bypass the dialog box. The lengths of the strands (calculated
from their perimeters and areas, corrected for end effects) are
displayed under the heading 'StrL' in the Results window. The threshold
values are displayed in the Session
Log.
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Steve Barrett November 2014 |
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