9.61. ITK Otsu Multiple Thresholds Image Filter

Threshold an image using multiple Otsu Thresholds.

Group (Subgroup)

ITKThresholding (Thresholding)

Description

This filter creates a labeled image that separates the input image into various classes. The filter computes the thresholds using the OtsuMultipleThresholdsCalculator and applies those thresholds to the input image using the ThresholdLabelerImageFilter . The NumberOfHistogramBins and NumberOfThresholds can be set for the Calculator. The LabelOffset can be set for the ThresholdLabelerImageFilter .

This filter also includes an option to use the valley emphasis algorithm from H.F. Ng, “Automatic thresholding for defect detection”, Pattern Recognition Letters, (27): 1644-1649, 2006. The valley emphasis algorithm is particularly effective when the object to be thresholded is small. See the following tests for examples: itkOtsuMultipleThresholdsImageFilterTest3 and itkOtsuMultipleThresholdsImageFilterTest4 To use this algorithm, simple call the setter: SetValleyEmphasis(true) It is turned off by default.* ScalarImageToHistogramGenerator

  • OtsuMultipleThresholdsCalculator

  • ThresholdLabelerImageFilter

Input Parameter(s)

Parameter Name

Parameter Type

Parameter Notes

Description

Number Of Thresholds

UInt8

Set/Get the number of thresholds. Default is 1.

Label Offset

UInt8

Set/Get the offset which labels have to start from. Default is 0.

Number Of Histogram Bins

Scalar Value

UInt32

Set/Get the number of histogram bins. Default is 128.

Valley Emphasis

Bool

Set/Get the use of valley emphasis. Default is false.

ReturnBinMidpoint

Bool

Should the threshold value be mid-point of the bin or the maximum? Default is to return bin maximum.

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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