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ReadMultipleDataMatrixCodes


Detects and recognizes several Data Matrix codes.

Syntax

C++
C#
 
void avl::ReadMultipleDataMatrixCodes
(
	const avl::Image& inImage,
	atl::Optional<const avl::Rectangle2D&> inRoi,
	atl::Optional<const avl::CoordinateSystem2D&> inRoiAlignment,
	const avl::DataMatrixCodeParams& inCodeParams,
	const avl::DataMatrixDetectionParams& inDetectionParams,
	int inMaxCodeCount,
	bool inAllowMultipleScales,
	atl::Array<avl::DataCode>& outDataMatrixCodes,
	atl::Array<avl::Path>& outCandidates,
	atl::Optional<avl::Rectangle2D&> outAlignedRoi = atl::NIL
)

Parameters

Name Type Range Default Description
inImage const Image& Input image
inRoi Optional<const Rectangle2D&> NIL Region of interest
inRoiAlignment Optional<const CoordinateSystem2D&> NIL Coordinate system for the region of interest
inCodeParams const DataMatrixCodeParams& Default initialized structure... Specification of codes that can be detected
inDetectionParams const DataMatrixDetectionParams& Default initialized structure... Specification of the way the codes are being detected
inMaxCodeCount int 0 - 2 Maximum number of codes to be found
inAllowMultipleScales bool False Specifies whether codes of different module sizes are expected
outDataMatrixCodes Array<DataCode>&
outCandidates Array<Path>& Diagnostic information about detection results
outAlignedRoi Optional<Rectangle2D&> NIL Input ROI after transformation (in the image coordinates)

Description

This filter detects and recognizes data matrix codes on an image.

Supported code types: ECC 200 and ECC 000-140.

Hints

  • Specify the range of possible codes on an image by setting the inCodeParams input. The more narrow is the specification, the faster the filter works.
    • Set inCodeParams.Polarity to specify whether dark-on-bright or bright-on-dark codes are to be read.
    • Specify the range of possible code sizes with inCodeParams.MinRowCount, inCodeParams.MaxRowCount, inCodeParams.MinColumnCount, inCodeParams.MinColumnCount.
    • Specify the range of possible module sizes (in pixels) with inCodeParams.MinModuleSize and inCodeParams.MaxModuleSize.
    • Set inCodeParams.ExpectedGapSize according to the following rules:
      • Zero – no gaps at all (modules are fully filled).
      • Small – gaps up to 25% of the module size.
      • Medium – gaps up to 50% of the module size; it may require a bigger Quiet Zone.
      • Large – gaps up to 75%; comes with no guarantee.
    • Modify inCodeParams.MaxRectangleRatio if you expect to work also with non-square codes. The value specifies maximal ratio between the length of the longer side to the length of the shorter side.
  • Specify the maximal number of codes on a single image by setting inMaxCodeCount.
  • If the codes may appear with different module sizes, also set inAllowMultipleScales to True.
  • If you are having problems with reading codes from low quality images, consider adding image morphology or smoothing.

Examples

DataMatrix on blurry image.

Low quality DataMatrix code.

DataMatrix on chip.

Rectangular DataMatrix code.

Remarks

For more information about local coordinate systems please refer to the following article.

See Also

ReadMultipleDataMatrixCodes