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

Name Type Range Description
inImage Image Input image
inRoi Region* Region of interest
inMinValue Real* Minimum value of a pixel that is considered foreground (Auto = -INF)
inMaxValue Real* Maximum value of a pixel that is considered foreground (Auto = +INF)
inHysteresis Real 0.0 - Defines how much the threshold criteria are lowered for pixels neighboring with other foreground pixels
outRegion Region Output region


Extraction of a region of objects that can be defined by a salient brightness.


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.


  • Define inMinValue to extract bright objects (brighter than the specified value).
  • Define inMaxValue to extract dark objects (darker than the specified value).
  • Use inHysteresis to allow weaker threshold for pixels neighboring with already extracted ones.


Hardware Acceleration

This operation is optimized for SSE2 technology for pixels of types: 1xUINT8, 3xUINT8, 1xInt16.

This operation supports automatic parallelization for multicore and multiprocessor systems.

Complexity Level

This filter is available on Basic Complexity Level.

Filter Group

This filter is member of ThresholdToRegion filter group.

See Also

  • ThresholdImage – Transforms each pixel value to maximum or minimum depending on whether they belong to the specified range.