LONI Visualization Tool (LONI_Viz)®
Selecting Data Sub-Sampling Ratios and Dimension Ranges
- LONI_Viz allows the user to select independent sub-sampling
rations and ranges for each dimension index of the data once the
header file (*.LHD) is parsed out. These choices significantly improve
on the speed of the viewer and decrease the resource requirements.
For example, if one wants to view a 10243 byte volume, one needs
more than 231 bytes (over 1 GB) of memory.
To our knowledge no viewer is
currently able to interpret real time such a huge volume. Thus we
allow the user to subsample in 1, 2 or all 3 dimensions at different
sub-sampling ratios. In the case, when the user is using LONI_Viz
to interactively draw contours and it is absolutely crucial that
the delineations are performed at the highest possible resolution
the user leaves the plane resolution at 1x1, but either subsamples
the between-plane dimension index or selects a proper (small)
subset of the range of the between-plane dimension. Figure 1
below illustrates the interactive window used to choose the desired
sub-sampling and sub-range parameters. And the cartoon on
Figure 2 shows how sub-sampling and sub-range selection decrease
the system requirements for large volumes and preserve the fast
interactive response of the viewer.
- Figure 1, Dialog window for independent (x, y, z) selection of
the sub-sampling ratios and dimension sub-ranges.
- Figure 2, Schematic representation of the effects of
sub-sampling & sub-ranging on the volume representation.
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