ReduceVol

DESCRIPTION

ReduceVol degrades the resolution of a volume data sample so that the volume can be more easily manipulated by Explorer. The user has complete control over the degradation of the voxel resolution for all three axes.

The intended purpose of ReduceVol is to allow easier, less time consuming manipulations of large volumetric data sets within the Explorer scientific visualization package. Modules such as Contour and Render can more easily ingest a smaller volume, and allow the researcher to have a faster response time. When the researcher set up Explorer to manipulate the volume the way he or she choses, ReduceVol can be turned off to allow the full resolution of the data set to be allowed to pass through the pipeline.

There are several subsampling functions that the user can use to degrade the resolution of the data set:

Average: All voxels within a radius of "n" are averaged together to produce the new volume set, where "n" is determined by the user's reduction percentage. Center Point: Every "nth" voxel is sent to the new volume set, where "n" is determined by the user's reduction percentage. Min Value The resulting data value is the min data value of all voxels in the nxn neighborhood of every nth point, where n is determined by the user's reduction percentage. Max Value Substitute "Max" for "Min" Min Absolute Value, Max Absolute Value As above... Percentile: The voxel value of user-specified percentile is used.

The input lattice may have any number of float variables, but must be 3D!

This module was originally to be called "Subsample," but there is already a (inappropriately named) module using that title.

INPUTS

Port: Input Lattice
Type: Lattice
Constraints: 3-D.
1..3-vector.
float..double.
uniform.
Input port from other modules. This must be a 3D lattice.

WIDGETS

Port: Subsampling Function
Type: Option Menu
Select subsampling function to use.

Port: X Compression Percentage
Type: Dial
Select percentage of total reduction along the X Axis. (i.e. 0.3 will subsample the X Axis to 30% of the normal amount of bins.)

Port: Y Compression Percentage
Type: Dial
Select percentage of total reduction along the Y Axis. (i.e. 0.3 will subsample the Y Axis to 30% of the normal amount of bins.)

Port: Z Compression Percentage
Type: Dial
Select percentage of total reduction along the Z Axis. (i.e. 0.3 will subsample the Z Axis to 30% of the normal amount of bins.)

Port: Yoked Compression
Type: Option Menu
Turning this to "ON" will yoke all of the compression dials together. Twiddling one dial will twiddle the others to the same value. This allows for constant compression across all three axes.

OUTPUTS

Port: Output Lattice
Type: Lattice
Constraints: 1..3-D.
1..3-vector.
float..double.
uniform.
This is the resultant 3D lattice.

PROBLEMS

- Subsampling between 50% and 100% results in no reduction of voxels.

SEE ALSO


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© The Numerical Algorithms Group Ltd, Oxford UK. 1996