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ReadMultipleBarcodes

Basic

Module: Barcodes

Detects and recognizes multiple barcodes on the input image.

Applications

To be used as an easy all-in-one solution for typical barcode reading applications.
Name Type Range Description
inImage Image Input image
inRoi Rectangle2D* Range of pixels to be processed
inRoiAlignment CoordinateSystem2D* Adjusts the barcode rectangle to the position of the inspected object
inBarcodeFormat BarcodeFormat* Format of the barcode
inMinGradientLength Real 0.0 - Minimal gradient length of edge pixels used for detecting barcodes
inBaseBarWidth Integer 1 - Estimated width of the thinnest bar
inDetectionScanCount Integer 1 - Number of scan lines used in detecting barcode
inReadingScanCount Integer 1 - Number of parallel scans run until first successful read
inScanWidth Integer 1 - Width of the single scan
inMinStrength Real 0.0 - Minimal strength of an extracted edge
inSmoothingStdDev Real 0.0 - Standard deviation of the gaussian smoothing applied to the profile extracted in each scan
inPolarity Polarity Specifies whether code is darker or brighter than the background
outBarcodePositions Rectangle2DArray Positions of the found barcodes
outDecodedTexts StringArray Decoded barcode content
outBarcodeFormats BarcodeFormatArray Decoded barcode format
outBarcodePolarities PolarityArray Decoded barcode polarity
outAlignedRoi Rectangle2D Input ROI after transformation (in the image coordinates)
outBarcodeCandidates Rectangle2DArray Places with high gradient values that are further investigated
diagGradientImage Image Image of gradient directions
diagScheduledScanSegments Segment2DArrayArray Scheduled scan segments

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

Two barcodes in a good quality image.

Two barcodes in a blurry image.

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.

Complexity Level

This filter is available on Basic Complexity Level.

Filter Group

This filter is member of ReadBarcodes filter group.

See Also

  • DecodeBarcode – Translates an array of bar widths to sequence of digits or text in accordance to the selected barcode standard.
  • RecognizeBarcode – Extracts information from a barcode located on the input image at a given position.