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CheckPresence_PixelAmount

Header:	AVL.h
Namespace:	avl
Module:	FoundationPro

Verifies object presence by analysing the amount of pixels that meet the specified criteria.

Applications: Quick and easy presence verification, e.g. for missing caps, screws, labels.

Syntax

void avl::CheckPresence_PixelAmount
(
	const avl::Image& inImage,
	const avl::ShapeRegion& inRoi,
	atl::Optional<const avl::CoordinateSystem2D&> inRoiAlignment,
	avl::HSxColorModel::Type inColorModel,
	int inBeginHue,
	int inEndHue,
	int inMinSaturation,
	atl::Optional<int> inMaxSaturation,
	atl::Optional<float> inMinBrightness,
	atl::Optional<float> inMaxBrightness,
	float inMinAmount,
	float inMaxAmount,
	bool& outIsPresent,
	atl::Optional<float&> outAmount = atl::NIL,
	atl::Optional<avl::Region&> outForeground = atl::NIL,
	atl::Optional<avl::ShapeRegion&> outAlignedRoi = atl::NIL,
	avl::Image& diagHsxImage
)

Parameters

Name	Type	Range	Default	Description
inImage	const Image&			Input image
inRoi	const ShapeRegion&			Location at which object presence is being checked
inRoiAlignment	Optional<const CoordinateSystem2D&>		NIL	Adjusts the region of interest to the position of the inspected object
inColorModel	HSxColorModel::Type			Selected color model
inBeginHue	int	0 - 255	0	Begin of the range of acceptable hue
inEndHue	int	0 - 255	255	End of the range of acceptable hue
inMinSaturation	int	0 - 255	128	Lowest acceptable saturation
inMaxSaturation	Optional<int>	0 - 255	NIL	Highest acceptable saturation
inMinBrightness	Optional<float>	0.0 -	128.0f	Lowest acceptable brightness
inMaxBrightness	Optional<float>	0.0 -	NIL	Highest acceptable brightness
inMinAmount	float	0.0 - 1.0	0.5f	Lowest acceptable fraction of pixels meeting the criteria
inMaxAmount	float	0.0 - 1.0	1.0f	Highest acceptable fraction of pixels meeting the criteria
outIsPresent	bool&			Flag indicating whether the object is present or not
outAmount	Optional<float&>		NIL	Fraction of pixels meeting the criteria
outForeground	Optional<Region&>		NIL	Region of pixels meeting the criteria
outAlignedRoi	Optional<ShapeRegion&>		NIL	Input ROI after transformation (in the image coordinates)
diagHsxImage	Image&			Image represented in chosen color model

Requirements

For input inImage only pixel formats are supported: 3⨯uint8, 1⨯uint8, 1⨯int8, 1⨯uint16, 1⨯int16, 1⨯int32, 1⨯real.

Read more about pixel formats in Image documentation.

Optional Outputs

The computation of following outputs can be switched off by passing value atl::NIL to these parameters: outAmount, outForeground, outAlignedRoi.

Description

The filter extracts foreground pixels by means of image thresholding and checks if their number comparing to the area of the whole ROI fits the range (inMinAmount, inMaxAmount). If the input image has 3 channels, the ThresholdToRegion_HSx filter is used for thresholding, and if the image has 1 channel (i.e. it is monochromatic), the simple ThresholdToRegion filter is performed. In the latter case only inMinBrightness and inMaxBrightness parameters matter.

Hints

If the object location is variable, Pass an appropriate local coordinate system to inRoiAlignment.
Define inRoi to specify the image location at which the object presence will be checked.
Set inBeginHue and inEndHue to values appropriate for correct objects.
Limit the ranges of inMinSaturation–inMaxSaturation and inMinBrightness–inMaxBrightness.
Verify that the outForeground output represents pixels belonging to correct objects.
Investigate the values that appear on the outAmount output, then set inMinAmount and inMaxAmount to values appropriate for correct objects.
When creating data previews, use outAlignedRoi and NOT inRoi as only the former will be properly aligned to the object location.

Examples

CheckPresence_PixelAmount performed on sample image with inMinAmount = 0.7. The defects are present in red circles.

Errors

List of possible exceptions:

Error type	Description
DomainError	Incorrect inMaxBrightness value in CheckPresence_PixelAmount.
DomainError	Incorrect inMinBrightness value in CheckPresence_PixelAmount.
DomainError	Region exceeds an input image in CheckPresence_PixelAmount.
DomainError	Not supported inImage pixel format in CheckPresence_PixelAmount. Supported formats: 3xUInt8, 1xUInt8, 1xInt8, 1xUInt16, 1xInt16, 1xInt32, 1xReal.