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Creates a region containing image pixels with values within the specified range.



public static void ThresholdToRegion
	AvlNet.Image inImage,
	NullableRef<AvlNet.Region> inRoi,
	float? inMinValue,
	float? inMaxValue,
	float inHysteresis,
	AvlNet.Region outRegion


Name Type Range Default Description
inImageAvlNet.ImageInput image.
inRoiAvlNet.NullableRef<AvlNet.Region>Region of interest. Default value: atl::NIL.
inMinValuefloat?128.0fMinimum value of a pixel that is considered foreground (Auto = -INF). Default value: 128.0f.
inMaxValuefloat?Maximum value of a pixel that is considered foreground (Auto = +INF). Default value: atl::NIL.
inHysteresisfloat<0.0f, INF>0.0fDefines how much the threshold criteria are lowered for pixels neighboring with other foreground pixels. Default value: 0.0f.
outRegionAvlNet.RegionOutput region.


The operation is a cousin of ThresholdImage yet computes a region instead of an image. The resulting region contains those pixels of the input image that meet one of the following conditions:

  • Pixel value is in range [inMinValue, inMaxValue].
  • Pixel value is in range [inMinValue-inHysteresis, inMinValue) or in range (inMaxValue, inMaxValue+inHysteresis] and in the processed image there is a path of consecutive pixels of value in range [inMinValue-inHysteresis, inMaxValue+inHysteresis] that connects the pixel being considered and any pixel with value in range [inMinValue, inMaxValue].

If any of the parameters inMinValue, inMaxValue is not set, it is assumed to be, accordingly, -infinity or infinity.

In the multichannel images the operation uses an average of channel values in each pixel.


ThresholdToRegion performed on the sample image with inMinValue = 80.0, inMaxValue = auto.

Hardware Acceleration

This operation is optimized for SSE2 technology for pixels of types: 1xUINT8, 3xUINT8, 1xINT16, 1xUINT16.

This operation is optimized for NEON technology for pixels of types: 1xUINT8, 3xUINT8, 1xINT16.

This operation supports automatic parallelization for multicore and multiprocessor systems.

Hardware acceleration settings may be manipulated with Settings class.


List of possible exceptions:

Error type Description
DomainError Region exceeds an input image in ThresholdToRegion.

Function Overrides

See also