find_2d_bar_codeT_find_2d_bar_codeFind2dBarCodefind_2d_bar_codeFind2dBarCodeFind2dBarCode (Operator)

Name

find_2d_bar_codeT_find_2d_bar_codeFind2dBarCodefind_2d_bar_codeFind2dBarCodeFind2dBarCode — Find regions that might contain a 2D bar code.

Warning

find_2d_bar_codefind_2d_bar_codeFind2dBarCodefind_2d_bar_codeFind2dBarCodeFind2dBarCode is obsolete and is only provided for reasons of backward compatibility. New applications should use the functionality in the chapter Identification / Data Code for reading 2D data code symbologies instead (see create_data_code_2d_modelcreate_data_code_2d_modelCreateDataCode2dModelcreate_data_code_2d_modelCreateDataCode2dModelCreateDataCode2dModel).

Signature

Description

find_2d_bar_codefind_2d_bar_codeFind2dBarCodefind_2d_bar_codeFind2dBarCodeFind2dBarCode searches in the image ImageImageImageImageImageimage for regions that might contain a 2D bar code. Candidate regions are returned in the array of regions CodeRegionCodeRegionCodeRegionCodeRegionCodeRegioncodeRegion. Whether such a region really contains a (readable) 2D bar code can only be determined with the help of the operator get_2d_bar_codeget_2d_bar_codeGet2dBarCodeget_2d_bar_codeGet2dBarCodeGet2dBarCode (or get_2d_bar_code_posget_2d_bar_code_posGet2dBarCodePosget_2d_bar_code_posGet2dBarCodePosGet2dBarCodePos).

Besides regions that might contain a 2D bar code, the operator passes further, internal information about the regions to the operator for extracting the data from a symbol (get_2d_bar_codeget_2d_bar_codeGet2dBarCodeget_2d_bar_codeGet2dBarCodeGet2dBarCode or get_2d_bar_code_posget_2d_bar_code_posGet2dBarCodePosget_2d_bar_code_posGet2dBarCodePosGet2dBarCodePos). This information is stored in a region descriptor and returned in the parameter CodeRegDescrCodeRegDescrCodeRegDescrCodeRegDescrCodeRegDescrcodeRegDescr.

Depending on the method for printing the bar code ('mode'"mode""mode""mode""mode""mode"), different image processing steps are performed. Together with other information about the 2D bar code, the actual printing method is part of a descriptor created with the help of the operator gen_2d_bar_code_descrgen_2d_bar_code_descrGen2dBarCodeDescrgen_2d_bar_code_descrGen2dBarCodeDescrGen2dBarCodeDescr and passed in the parameter BarCodeDescrBarCodeDescrBarCodeDescrBarCodeDescrBarCodeDescrbarCodeDescr.

In the case of difficult conditions, additional control parameters can be passed to the operator with the help of the (optional) generic parameters GenParamNamesGenParamNamesGenParamNamesGenParamNamesGenParamNamesgenParamNames and GenParamValuesGenParamValuesGenParamValuesGenParamValuesGenParamValuesgenParamValues, in the form of descriptor-value pairs. One group of parameters describes the appearance of the symbols in the actual images, e.g., the expected size of data elements in pixels. The operator will then check candidate regions against the specified criteria. Suitable values can be determined from the real images, e.g., by manually selecting a region with a bar code and then applying the corresponding operator. If the specification of such parameters does not lead to successfully extracted regions, the user can influence the underlying image processing operators directly with the help of a second group of parameters. As the image processing steps taken depend on the printing method, different parameters are to be applied.

• Parameter that will be passed on in CodeRegDescrCodeRegDescrCodeRegDescrCodeRegDescrCodeRegDescrcodeRegDescr:

  'module_width'

  Mean size of a module (data element) in pixels. From this quantity, a set of other parameters will be derived. A module should have a size of 4 to 16 pixels in order to be recognized successfully.

    GenParamValues: > 0
    default:        10
  

• Parameters for the printing method 'printed'"printed""printed""printed""printed""printed":

  The following parameters are used to limit the set of candidate regions with the help of region features. To prevent the use of a certain feature, the corresponding parameter must be set to -1.

  'anisometry_max'

  Maximum anisometry (see operator eccentricityeccentricityEccentricityeccentricityEccentricityEccentricity).

   GenParamValues: > 1  (-1: feature not used)
   default:        1.45
  

  'compactness_min'

  Minimum compactness (see operator compactnesscompactnessCompactnesscompactnessCompactnessCompactness).

    GenParamValues: > 1  (-1: feature not used)
    default:        1.2
  

  'compactness_max'

  Maximum compactness.

    GenParamValues: >= 'compactness_min'"compactness_min""compactness_min""compactness_min""compactness_min""compactness_min"  (-1: feature not used)
    default:        3.0
  

  'circularity_max'

  Maximum circularity (see operator circularitycircularityCircularitycircularityCircularityCircularity).

    GenParamValues: 0...1  (-1: feature not used)
    default:        0.8
  

  'circularity_min'

  Minimum circularity.

    GenParamValues: <= 'circularity_max'"circularity_max""circularity_max""circularity_max""circularity_max""circularity_max"  (-1: feature not used)
    default:        0.45
  

  'deviation_min'

  Minimum deviation of gray values (see operator intensityintensityIntensityintensityIntensityIntensity).

    GenParamValues: > 1.0
    default:        20.0
  

  The following parameters are automatically derived from the size of a module, 'module_width'"module_width""module_width""module_width""module_width""module_width", and from parameters of the bar code descriptor BarCodeDescrBarCodeDescrBarCodeDescrBarCodeDescrBarCodeDescrbarCodeDescr (see operator gen_2d_bar_code_descrgen_2d_bar_code_descrGen2dBarCodeDescrgen_2d_bar_code_descrGen2dBarCodeDescrGen2dBarCodeDescr). However, they can be adjusted individually, too.

  ATTENTION: If you want to set 'module_width'"module_width""module_width""module_width""module_width""module_width" together with other parameters, make sure set 'module_width'"module_width""module_width""module_width""module_width""module_width" BEFORE the others!

  'mean_mask_size_1'

  Mask size for the first smoothing of the image.

    GenParamValues: >= 3
    default:        2.5*'module_width'"module_width""module_width""module_width""module_width""module_width"
  

  'mean_mask_size_2'

  Mask size for the second smoothing of the image.

    GenParamValues: >= 5
    default:        10.0*'module_width'"module_width""module_width""module_width""module_width""module_width"
  

  'area_min'

  Minimum size of the symbol in pixels squared.

    GenParamValues: > 0
    default:        0.25 * 'module_width'"module_width""module_width""module_width""module_width""module_width"^2 * 'columns_min'"columns_min""columns_min""columns_min""columns_min""columns_min" * 'rows_min'"rows_min""rows_min""rows_min""rows_min""rows_min"
  

  'area_max'

  Maximum size of the symbol in pixels squared.

    GenParamValues: >= 'area_min'"area_min""area_min""area_min""area_min""area_min"
    default:        4.00 * 'module_width'"module_width""module_width""module_width""module_width""module_width"^2 * 'columns_min'"columns_min""columns_min""columns_min""columns_min""columns_min" * 'rows_min'"rows_min""rows_min""rows_min""rows_min""rows_min"
  

  'closing_mask_rad'

  Mask size for calling the operator closing_circleclosing_circleClosingCircleclosing_circleClosingCircleClosingCircle with a test region..

    GenParamValues: > 0
    default:        'module_width'"module_width""module_width""module_width""module_width""module_width"
  

• Parameters for the printing method 'engraved_darkfield'"engraved_darkfield""engraved_darkfield""engraved_darkfield""engraved_darkfield""engraved_darkfield":

  'compactness_min'

  Minimum compactness (see operator compactnesscompactnessCompactnesscompactnessCompactnessCompactness).

    GenParamValues: > 1.0  (-1: feature not used)
    default:        1.2
  

  'compactness_max'

    GenParamValues: >= 'compactness_min'"compactness_min""compactness_min""compactness_min""compactness_min""compactness_min"  (-1: feature not used)
    default:        3.0
  

  'edge_thresh'

  Maximum compactness.

    GenParamValues: 0...255
    default:        120
  

  'region_rect2_rel'

  Relation between the areas of the region and the smallest surrounding rectangle.

    GenParamValues: < 1.0
    default:        0.7
  

  'median_mask_rad'

  Mask size for the initial median filtering (see operator median_imagemedian_imageMedianImagemedian_imageMedianImageMedianImage).

    GenParamValues: > 0
    default:        0.1 * 'module_width'"module_width""module_width""module_width""module_width""module_width" + 0.5
  

• Parameters for the printing method 'engraved_lightfield'"engraved_lightfield""engraved_lightfield""engraved_lightfield""engraved_lightfield""engraved_lightfield":

  'anisometry_max'

  Maximum anisometry (see operator eccentricityeccentricityEccentricityeccentricityEccentricityEccentricity).

    GenParamValues: > 1  (-1: feature not used)
    default:        1.45
  

  'compactness_min'

  Minimum compactness (see operator compactnesscompactnessCompactnesscompactnessCompactnessCompactness).

    GenParamValues: > 1  (-1: feature not used)
    default:        1.2
  

  'compactness_max'

  Maximum compactness.

    GenParamValues: >= 'compactness_min'"compactness_min""compactness_min""compactness_min""compactness_min""compactness_min"  (-1: feature not used)
    default:        3.0
  

  'circularity_max'

  Maximum circularity (see operator circularitycircularityCircularitycircularityCircularityCircularity).

    GenParamValues: 0...1  (-1: feature not used)
    default:        0.8
  

  'circularity_min'

  Minimum circularity.

    GenParamValues: <= 'circularity_max'"circularity_max""circularity_max""circularity_max""circularity_max""circularity_max"  (-1: feature not used)
    default:        0.45
  

  'deviation_min'

  Minimum deviation of gray values (see operator intensityintensityIntensityintensityIntensityIntensity).

    GenParamValues: > 1.0
    default:        20.0
  

  'mean_mask_size'

  Mask size for smoothing the image.

    GenParamValues: >= 3
    default:        10*'module_width'"module_width""module_width""module_width""module_width""module_width"
  

  'area_min'

  Minimum size of the symbol in pixels squared.

    GenParamValues: > 0
    default:        0.25 * 'module_width'"module_width""module_width""module_width""module_width""module_width"^2 * 'columns_min'"columns_min""columns_min""columns_min""columns_min""columns_min" * 'rows_min'"rows_min""rows_min""rows_min""rows_min""rows_min"
  

  'area_max'

  Maximum size of the symbol in pixels squared.

    GenParamValues: >= 'area_min'"area_min""area_min""area_min""area_min""area_min"
    default:        4.00 * 'module_width'"module_width""module_width""module_width""module_width""module_width"^2 * 'columns_min'"columns_min""columns_min""columns_min""columns_min""columns_min" * 'rows_min'"rows_min""rows_min""rows_min""rows_min""rows_min"
  

  'closing_mask_rad'

  Mask size for calling the operator closing_circleclosing_circleClosingCircleclosing_circleClosingCircleClosingCircle with a test region.

    GenParamValues: > 0
    default:        'module_width'"module_width""module_width""module_width""module_width""module_width"
  

  'opening_mask_rad'

  Mask size for calling the operator opening_circleopening_circleOpeningCircleopening_circleOpeningCircleOpeningCircle with a test region.

    GenParamValues: > 0
    default:        1.5*'module_width'"module_width""module_width""module_width""module_width""module_width"
  

Parallelization

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Processed without parallelization.

Parameters

Result

The operator find_2d_bar_codefind_2d_bar_codeFind2dBarCodefind_2d_bar_codeFind2dBarCodeFind2dBarCode returns the value 2 (H_MSG_TRUE) if the given parameters are correct. Otherwise, an exception will be raised.

Possible Predecessors

gen_2d_bar_code_descrgen_2d_bar_code_descrGen2dBarCodeDescrgen_2d_bar_code_descrGen2dBarCodeDescrGen2dBarCodeDescr

Possible Successors

get_2d_bar_codeget_2d_bar_codeGet2dBarCodeget_2d_bar_codeGet2dBarCodeGet2dBarCode, get_2d_bar_code_posget_2d_bar_code_posGet2dBarCodePosget_2d_bar_code_posGet2dBarCodePosGet2dBarCodePos

Module

Data Code