Downsample3D

MacroModule

genre	Resample
author	MeVis Medical Solutions AG
package	MeVisLab/Standard
definition	Geometry.def
see also	Resample3D
keywords	resample, interpolate, preview

Purpose

The Downsample3D macro module performs a downsampling operation on the input image according to a given size or resolution restriction.

The restriction can be specified with respect to a maximum image size for each dimension, a minimum voxel size or a maximum total image size in megabytes. Dependent on the size and resolution of the current input image, the module determines the scaling factor for each spatial dimension and computes the downsampled image at its output. If no scaling is necessary, i.e. if the input image is small enough to fulfill the size restriction, the input image is passed directly to the output.

Details

For restriction modes MaxVoxelsPerDim and MinVoxelDist, the scaling factors are computed independently for each dimension. For the MaxMBytes… restriction modes, a global size restriction for the image is specified and the scaling factors can not be computed independently. There are three different modes that differ in the way the global scaling requirement is distributed over the three dimensions. If MaxMBytesIsotropic is selected, the factors are chosen such that the resulting image is as isotropic as possible, i.e. dimensions with high spatial resolution are downsampled at a higher rate than dimensions with low resolution. With MaxMBytesCubic, the scaling factors are chosen such that the image extents (in voxels) in the three dimensions are as close as possible, whereas in the MaxMBytesUniform mode the scaling factors are preferably equal to each other. Scaling factors are always larger or equal to 1, i.e. the image is never upsampled in any dimension.

Windows

Default Panel

Input Fields

inImage

name: inImage, type: Image, deprecated name: imageIn

Output Fields

outImage

name: outImage, type: Image, deprecated name: imageOut

Parameter Fields

Field Index

Allow interpolation: Bool	Voxel Size: Vector3
Image forwarded directly without resampling: Bool	zoom: Vector3
Image Size: Vector3
Limit: Float
Method: Enum
noInputImgBytes: Integer
Restriction: Enum
Scaling: Vector3

Visible Fields

Restriction

name: restriction, type: Enum, default: MaxMBytesIsotropic

Defines the restriction mode.

Values:

Title	Name	Deprecated Name	Description
Max Voxels Per Dim	MaxVoxelsPerDim	MAX_VOXELS_PER_DIM	Select the scaling factors such that the image extent in voxels for each spatial dimension is equal or below the limit.
Max MBytes Isotropic	MaxMBytesIsotropic	MAX_MBYTES_ISOTROPIC	Select the scaling factors such that the total image size in megabytes is equal or below the limit, preferring an isotropic output image.
Max MBytes Cubic	MaxMBytesCubic	MAX_MBYTES_CUBIC	Select the scaling factors such that the total image size in megabytes is equal or below the limit, preferring a cubic output image.
Max MBytes Uniform	MaxMBytesUniform	MAX_MBYTES_UNIFORM	Select the scaling factors such that the total image size in megabytes is equal or below the limit, preferring uniform scaling.
Min Voxel Dist	MinVoxelDist	MIN_VOXEL_DIST	Select the scaling factors such that the voxel distance in millimeters for each spatial dimension is equal or above the limit.

Limit

name: limit, type: Float, default: 0

Sets the size limit in voxels, megabytes or millimeters, depending on the Restriction setting.

Allow interpolation

name: interpolate, type: Bool, default: FALSE

If checked, scaling factors are allowed to be fractional, otherwise only integer scaling factors are applied.

Method

name: method, type: Enum, default: Nearest_Neighbor

Defines the method to interpolate an image for compression.

See Resample3D for details.

Values:

Title	Name
Nearest Neighbor	Nearest_Neighbor
Triangle/Linear	Triangle/Linear
Hermite	Hermite
Blackman	Blackman
Hamming	Hamming
Hanning	Hanning
Gaussian	Gaussian
Bell/Quadratic	Bell/Quadratic
Cubic B-Spline	Cubic_B-Spline
Catrom	Catrom
Mitchell et al	Mitchell_et_al
Trunc Sinc 4	Trunc_Sinc_4
Lanczos 2	Lanczos_2
Lanczos 3	Lanczos_3
Lanczos 4	Lanczos_4
Box NNB	Box_NNB

Scaling

name: scaling, type: Vector3, persistent: no

Shows the resulting image scaling.

Image Size

name: imageSize, type: Vector3, persistent: no

Shows the resulting image size.

Voxel Size

name: voxelSize, type: Vector3, persistent: no

Shows the resulting image voxel size.

Image forwarded directly without resampling

name: direct, type: Bool, persistent: no

If checked, the original input image is being forwarded to the module’s output.

Hidden Fields

noInputImgBytes

name: noInputImgBytes, type: Integer, persistent: no

zoom

name: zoom, type: Vector3, persistent: no