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DetectMultipleBarcodes

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Module: Barcodes

Determines the positions of multiple barcodes on the input image.

Applications

Detection of barcodes, but without actual recognition. Usually followed by a RecognizeBarcode filter.
Name Type Range Description
Input value
 inImage Image Input image
Input value
 inFormat BarcodeFormat* Format of the barcode
Input value
 inMinGradientLength Real 0.0 - Minimal gradient length of edge pixels used for detecting barcodes
Input value
 inBaseBarWidth Integer 1 - Estimated width of the thinnest bar
Input value
 inScanCount Integer 1 - Number of scan lines used in detecting barcode
Input value
 inScanWidth Integer 1 - Width of the single scan
Input value
 inMinStrength Real 0.0 - Minimal strength of an extracted edge
Input value
 inSmoothingStdDev Real 0.0 - Standard deviation of the gaussian smoothing applied to the profile extracted in each scan
Input value
 inPolarity Polarity Specifies whether code is darker or brighter than the background
Output value
 outBarcodePositions Rectangle2DArray Positions of the found barcodes
Output value
 outBarcodePolarities PolarityArray Polarities of the found barcodes
Output value
 outBarcodeCandidates Rectangle2DArray Places with high gradient values that are further investigated
Diagnostic input
 diagGradientImage Image Image of gradient directions

Hints

  • Connect inImage with the output of your image acquisition filter.
  • Select inFormat 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

Filter finds barcodes rotated by any angle.

Low quality barcode printed on plastic foil.

Barcode on package wrapped in plastic foil.

Barcode on blurry image.

Barcode on reflective and wrapped surface.

Barcode on standard 330ml can.

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.

Complexity Level

This filter is available on Advanced Complexity Level.

Filter Group

This filter is member of DetectBarcodes filter group.

See Also

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