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CheckPresence_PixelAmount

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

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

Only the following inImage pixel formats are supported: 3xuint8, 1xuint8, 1xint8, 1xuint16, 1xint16, 1xint32, 1xreal

Applications

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

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

Connect the inImage input with an appropriate image source. Make sure that this image is available (the program was previously run).
If the object location is variable, Connect 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

Description of usage of this filter can be found in examples and tutorial: Finding Razor Head Defects.

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

Errors

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

Error type	Description
DomainError	Incorrect inMinBrightness value in CheckPresence_PixelAmount.
DomainError	Incorrect inMaxBrightness value in CheckPresence_PixelAmount.

Complexity Level

This filter is available on Basic Complexity Level.

Filter Group

This filters is member of CheckPresence filter group.