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ThresholdToRegion_Dynamic
Thresholds an image relatively to the average pixel value in a local rectangular neighborhood.
Header: | AVL.h |
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Syntax
void avl::ThresholdToRegion_Dynamic ( const avl::Image& inImage, atl::Optional<const avl::Region&> inRoi, atl::Optional<const avl::Region&> inSourceRoi, int inRadiusX, atl::Optional<int> inRadiusY, atl::Optional<float> inMinRelativeValue, atl::Optional<float> inMaxRelativeValue, float inHysteresis, avl::Region& outRegion, avl::Image& diagBaseImage )
Parameters
Name | Type | Range | Default | Description | |
---|---|---|---|---|---|
inImage | const Image& | Input image | |||
inRoi | Optional<const Region&> | NIL | Region in which pixels are written | ||
inSourceRoi | Optional<const Region&> | NIL | Region from which pixels are read | ||
inRadiusX | int | 0 - 65536 | 5 | Horizontal radius of internal mean blur | |
inRadiusY | Optional<int> | 0 - 65536 | NIL | Vertical radius of internal mean blur (Auto = inRadiusX) | |
inMinRelativeValue | Optional<float> | 5.0f | Minimum relative value of a pixel that is considered foreground (Auto = -INF) | ||
inMaxRelativeValue | Optional<float> | NIL | Maximum relative value of a pixel that is considered foreground (Auto = +INF) | ||
inHysteresis | float | 0.0 - | 0.0f | Defines how much the threshold criteria are lowered for pixels neighboring with other foreground pixels | |
outRegion | Region& | Output region | |||
diagBaseImage | Image& | Diagnostic blurred image. |
Description
The operation is a cousin of ThresholdImage_Dynamic yet computes a region instead of an image. The resulting region contains only those pixels of the input image, which are brighter at least by inMinRelativeValue and at most by inMaxRelativeValue than the local average. If any of the parameters inMinRelativeValue, inMaxRelativeValue is not set, it is assumed to be, accordingly, -infinity or infinity.
Pixel neighbourhood used to compute the local average is a rectangle of dimensions centered at the pixel being processed.
In the multichannel images the operation uses an average of channel values in each pixel.
Hints
- Define inMinRelativeValue to extract objects which are brighter than the neighborhood.
- Define inMaxRelativeValue to extract objects which are darker than the neighborhood.
- Increase inRadiusX (and optionally inRadiusY) to define a bigger neighborhood.
Examples
See Also
- ThresholdImage_Dynamic – Thresholds an image relatively to some value calculated in a local rectangular neighbourhood.