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ReadMultipleBarcodes

Header:	FIL.h
Namespace:	fil

Detects and recognizes multiple barcodes on the input image.

Syntax

void fil::ReadMultipleBarcodes
(
	const fil::Image& inImage,
	ftl::Optional<const fil::Rectangle2D&> inRoi,
	ftl::Optional<const fil::CoordinateSystem2D&> inRoiAlignment,
	ftl::Optional<fil::BarcodeFormat::Type> inBarcodeFormat,
	float inMinGradientLength,
	int inBaseBarWidth,
	int inDetectionScanCount,
	const int inReadingScanCount,
	const int inScanWidth,
	const float inMinStrength,
	const float inSmoothingStdDev,
	ftl::Array<fil::Rectangle2D>& outBarcodePositions,
	ftl::Array<ftl::String>& outDecodedTexts,
	ftl::Optional<ftl::Array<fil::BarcodeFormat::Type>&> outBarcodeFormats = ftl::NIL,
	ftl::Optional<fil::Rectangle2D&> outAlignedRoi = ftl::NIL,
	ftl::Optional<ftl::Array<fil::Rectangle2D>&> outBarcodeCandidates = ftl::NIL,
	fil::Image& diagGradientImage,
	ftl::Array<ftl::Array<fil::Segment2D> >& diagScheduledScanSegments
)

Parameters

Name	Type	Range	Default	Description
inImage	const Image&			Input image
inRoi	Optional<const Rectangle2D&>		NIL	Range of pixels to be processed
inRoiAlignment	Optional<const CoordinateSystem2D&>		NIL	Adjusts the barcode rectangle to the position of the inspected object
inBarcodeFormat	Optional<BarcodeFormat::Type>		EAN13	Format of the barcode
inMinGradientLength	float	0.0 -	8.0f	Minimal gradient length of edge pixels used for detecting barcodes
inBaseBarWidth	int	1 -	3	Estimated width of the thinnest bar
inDetectionScanCount	int	1 -	5	Number of scan lines used in detecting barcode
inReadingScanCount	const int	1 -	5	Number of parallel scans run until first successful read
inScanWidth	const int	1 -	5	Width of the single scan
inMinStrength	const float	0.0 -	5.0f	Minimal strength of an extracted edge
inSmoothingStdDev	const float	0.0 -	0.25f	Standard deviation of the gaussian smoothing applied to the profile extracted in each scan
outBarcodePositions	Array<Rectangle2D>&			Positions of the found barcodes
outDecodedTexts	Array<String>&			Decoded barcode content
outBarcodeFormats	Optional<Array<BarcodeFormat::Type>&>		NIL	Decoded barcode format
outAlignedRoi	Optional<Rectangle2D&>		NIL	Input ROI after transformation (in the image coordinates)
outBarcodeCandidates	Optional<Array<Rectangle2D>&>		NIL	Places with high gradient values that are further investigated
diagGradientImage	Image&			Image of gradient directions
diagScheduledScanSegments	Array<Array<Segment2D> >&			Scheduled scan segments

Optional Outputs

The computation of following outputs can be switched off by passing value ftl::NIL to these parameters: outBarcodeFormats, outAlignedRoi, outBarcodeCandidates.

Description

This filter works as a composition of DetectMultipleBarcodes and RecognizeBarcode filters.

Hints

Connect inImage with the output of your image acquisition filter.
Select inBarcodeFormat according to the type of codes you want to read. If you choose the wrong format, the codes will not be recognized. Setting its value to Auto can increase the computation time considerably. Furthermore, the Auto value causes detection of UPC-A codes as EAN-13 codes.

If the image quality is low, increase inMinGradientLength or increase inSmoothingStdDev. The diagGradientImage output shows how this affects an intermediate image.
If the image resolution is high, increase inBaseBarWidth or resize/downsample the input image.

Examples

Rotated barcode.

Low quality barcode printed on plastic foil.

Barcode on package wrapped in plastic foil.

Barcode on blurry image.

Barcode on standard 330ml can.

Barcode on reflective and wrapped surface.

EAN-13 with add-on 2 used to indicate a book edition.

EAN-13 with add-on 5 to give a suggestion for the price.

Remarks

Minimal bar width requirement

To provide precise detection of the barcode width of the thinnest bar should be at least 1.5 pixels.

Depending on the barcode format guard or start/end code patterns must be readable.

Pharmacode usage

The pharmacode barcode type can be read correctly in both directions. To get results from both directions use a Pharmacode and PharmacodeInversed barcode types.

Before decoding a Pharmacode the code orientation angle is normalized to a range from -45° to 135° what makes the code decoding more stable

Results of reading using a different Pharmacode directions: Pharmacode = 23 and PharmacodeInversed = 16.

Using a relative coordinate systems

Read more about Local Coordinate Systems in Machine Vision Guide: Local Coordinate Systems.

Hardware Acceleration

This operation supports automatic parallelization for multicore and multiprocessor systems.