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ThresholdToRegion

Module:	FoundationBasic

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

Applications

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

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

Description

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.

Hints

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.

Examples

Description of usage of this filter can be found in examples and tutorial: Badge Measurement, Button Presence, Fuses, Inset Distances, Molybdenum Foil, Seat Mount, Waffles, Washers, Count Nails, Finding PCB Missing Covering, Count the Mounts, Detecting Chocolate Coverage on a Wafer, Classify the Mounts, Sorting Blobs.

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.

Errors

This filter can throw an exception to report error. Read how to deal with errors in Error Handling.

List of possible exceptions:

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

Complexity Level

This filter is available on Basic Complexity Level.

Filter Group

This filter is member of ThresholdToRegion filter group.