11.13. ITK Binary Projection Image Filter

Collapses a 3D volume to a 2D image using a logical-OR projection: a pixel is foreground if any voxel along the axis is foreground.

Group (Subgroup)

ITKImageStatistics (ImageStatistics)

Description

A projection collapses a 3D volume into a 2D image by combining all voxels along one axis into a single output value. This filter uses a binary (logical-OR) rule: for each line of voxels parallel to the selected axis, the output pixel is set to the Foreground Value if any voxel along that line equals the Foreground Value; otherwise it is set to the Background Value. The result has one fewer dimension than the input.

Use binary projection to answer “is this feature present anywhere along this axis?” — for example, to flatten a segmented 3D mask into a 2D footprint showing where labeled material exists at any depth.

Note

This filter changes the dimensionality of the Image Geometry that the data is tied to. As a side effect, every Data Array stored in the same Attribute Matrix as the input and output array is also affected.

Parameter Guidance

  • Projection Dimension — the axis to collapse, given as an index: 0, 1, or 2. Index 0 is the slowest-moving dimension. The output image keeps the two remaining axes.

  • Foreground Value — the voxel value treated as “foreground.” An output pixel is set to this value if any voxel along the collapsed line matches it. Defaults to 1.

  • Background Value — the value written to output pixels where no foreground voxel was found along the line. Defaults to 0.

  • Perform In-Place — when enabled, the projection replaces the input geometry rather than creating a new one.

Required Input Sources

Operates on any scalar image — typically from Read Image, Read Images [3D Stack], or the output of a prior ITK image filter.

Input Parameter(s)

Parameter Name

Parameter Type

Parameter Notes

Description

Projection Dimension

Scalar Value

UInt32

The dimension index to project. 0=Slowest moving dimension.

Perform In-Place

Bool

Performs the projection in-place for the given Image Geometry

Foreground Value

Scalar Value

Float64

Set the value in the image to consider as ‘foreground’. Defaults to maximum value of PixelType. Subclasses may alias this to DilateValue or ErodeValue.

Background Value

Scalar Value

Float64

Set the value used as ‘background’. Any pixel value which is not DilateValue is considered background. BackgroundValue is used for defining boundary conditions. Defaults to NumericTraits::NonpositiveMin() .

Input Cell Data

Parameter Name

Parameter Type

Parameter Notes

Description

Image Geometry

Geometry Selection

Image

Select the Image Geometry Group from the DataStructure.

Input Cell Data

Array Selection

Allowed Types: int8, uint8, int16, uint16, int32, uint32, int64, uint64, float32, float64

The image data that will be processed by this filter.

Output Data

Parameter Name

Parameter Type

Parameter Notes

Description

Created Image Geometry

String

The name of the projected geometry

Output Image Data Array

DataObjectName

The result of the processing will be stored in this Data Array.

Example Pipelines

DREAM3D-NX Help

If you need help, need to file a bug report or want to request a new feature, please head over to the DREAM3DNX-Issues GitHub site where the community of DREAM3D-NX users can help answer your questions.