11.30. ITK Gradient Magnitude Image Filter

Computes the gradient magnitude (edge strength) of an image at each pixel.

Group (Subgroup)

ITKImageGradient (ImageGradient)

Description

The gradient magnitude is the length of the local intensity gradient vector — large where the image changes rapidly (edges) and near zero in smooth regions. This filter estimates it directly from simple finite differences between neighboring pixels, which makes it fast but sensitive to noise; for noisy data prefer the smoothed variant ITK Gradient Magnitude Recursive Gaussian Image Filter, which blurs with a Gaussian before differentiating.

Parameter Guidance

  • Use Image Spacing: When on (default), derivatives are computed in physical space using the image spacing, giving results in intensity units per physical length unit. When off, spacing is ignored and the gradient is computed in isotropic voxel space.

Required Input Sources

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

Input Parameter(s)

Parameter Name

Parameter Type

Parameter Notes

Description

Use Image Spacing

Bool

Set/Get whether or not the filter will use the spacing of the input image in the computation of the derivatives. Use On to compute the gradient in physical space; use Off to ignore image spacing and to compute the gradient in isotropic voxel space. Default is On.

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 Cell Data

Parameter Name

Parameter Type

Parameter Notes

Description

Output Cell Data

DataObjectName

The result of the processing will be stored in this Data Array inside the same group as the input data.

Example Pipelines

DREAM3D-NX Help

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