VerifyBarcodeMethod Property (ReaderSettings)

In This Topic

Gets or sets method that verifies the information about barcode found by barcode reader.

Syntax

Visual Basic
C#
Managed Extensions for C++
C++/CLI

'Declaration

<XmlIgnoreAttribute()>
Public Property VerifyBarcodeMethod As VerifyBarcodeDelegate

[XmlIgnore()]
public VerifyBarcodeDelegate VerifyBarcodeMethod { get; set; }

[XmlIgnore()]
public: __property VerifyBarcodeDelegate* get_VerifyBarcodeMethod();
public: __property void set_VerifyBarcodeMethod(
   VerifyBarcodeDelegate* value
);

[XmlIgnore()]
public:
property VerifyBarcodeDelegate^ VerifyBarcodeMethod {
   VerifyBarcodeDelegate^ get();
   void set(VerifyBarcodeDelegate^ value);
}

Remarks

Method that verifies the information about barcode found by barcode reader executes every time when the "barcode" is found by the barcode reader.

Application can analyze information about found barcode and change Confidence if this is necessary.

Method that verifies the information about barcode found can be used in automatic or iteration recognition mode and increase quality of recognition.

Example

This example generates Code 39 barcode with user-defined base 1000 cheksum, and read it using check barcode checksum in verify barcode method.

VB.NET

   
   
Imports Vintasoft.Barcode   
Imports Vintasoft.Imaging   
   
''' <summary>
''' Test that shows how to set the delegate for barcode verification and
''' verify found barcodes during the barcode recognition process.
''' </summary>
Class UserDefinedChecksumExample   
    ''' <summary>
    ''' Runs the test.
    ''' </summary>
    Public Shared Sub Run()   
        Dim value As String = "1234567890AbC"   
   
        ' create the barcode writer
        Using writer As New BarcodeWriter()   
            ' specify that writer must generate Code39 barcode
            writer.Settings.Barcode = BarcodeType.Code39   
   
            ' create the barcode reader
            Using reader As New BarcodeReader()   
                ' specify that reader must search for Code39 barcodes only
                reader.Settings.ScanBarcodeTypes = BarcodeType.Code39   
                ' specify that reader must search for barcode with 100% confidence only
                reader.Settings.MinConfidence = 100   
                ' specify that reader must use barcodes in automatic mode
                reader.Settings.AutomaticRecognition = True   
                ' specify that reader must search for 1 barcode
                reader.Settings.ExpectedBarcodes = 1   
   
                ' set the barcode value without checksum
                writer.Settings.Value = value   
                ' create image with barcode without checksum
                Using barcodeNoChecksumImage As VintasoftBitmap = writer.GetBarcodeAsVintasoftBitmap()   
                    ' set the barcode value with checksum
                    writer.Settings.Value = value & GenerateChecksum(value)   
                    ' create image with barcode with checksum
                    Using barcodeWithMyChecksumImage As VintasoftBitmap = writer.GetBarcodeAsVintasoftBitmap()   
                        ' specify delegate to a method for barcode verification
                        reader.Settings.VerifyBarcodeMethod = AddressOf VerifyBarcodeMethod   
   
                        ' read barcodes from barcode image without checksum,
                        ' barcode reader will not find barcode
                        Dim infos As IBarcodeInfo() = reader.ReadBarcodes(barcodeNoChecksumImage)   
                        Console.WriteLine("Scan (NoChecksum):")   
                        For i As Integer = 0 To infos.Length - 1   
                            Console.WriteLine(infos(i).Value)   
                        Next   
   
                        ' read barcodes from barcode image with checksum,
                        ' barcode reader will find 1 barcode
                        infos = reader.ReadBarcodes(barcodeWithMyChecksumImage)   
                        Console.WriteLine("Scan (MyChecksum):")   
                        For i As Integer = 0 To infos.Length - 1   
                            Console.WriteLine(infos(i).Value)   
                        Next   
                    End Using   
                End Using   
            End Using   
        End Using   
    End Sub   
   
    ''' <summary>
    ''' Generates checksum modulo 1000.
    ''' </summary>
    Private Shared Function GenerateChecksum(value As String) As String   
        Dim checkSum As Integer = 0   
        For i As Integer = 0 To value.Length - 1   
            checkSum += CByte(AscW(value(i))) * (i + 1)   
            checkSum = checkSum Mod 1000   
        Next   
        ' result - [000..999]
        Return checkSum.ToString().PadLeft(3, "0"C)   
    End Function   
   
    ''' <summary>
    ''' Verifies the barcode during the barcode recognition process.
    ''' </summary>
    Private Shared Sub VerifyBarcodeMethod(reader As BarcodeReader, barcodeInfo As IBarcodeInfo)   
        If TestChecksum(barcodeInfo.Value) Then   
            barcodeInfo.Confidence = 100   
        Else   
            barcodeInfo.Confidence = 0   
        End If   
    End Sub   
   
    ''' <summary>
    ''' Tests checksum in barcode value.
    ''' </summary>
    Private Shared Function TestChecksum(barcodeValue As String) As Boolean   
        Dim value As String = barcodeValue.Substring(0, barcodeValue.Length - 3)   
        Dim readChecksum As String = barcodeValue.Substring(barcodeValue.Length - 3)   
        Return readChecksum = GenerateChecksum(value)   
    End Function   
   
End Class


using System;

using Vintasoft.Barcode;
using Vintasoft.Imaging;

/// <summary>
/// Test that shows how to set the delegate for barcode verification and
/// verify found barcodes during the barcode recognition process.
/// </summary>
class UserDefinedChecksumExample
{
    /// <summary>
    /// Runs the test.
    /// </summary>
    public static void Run()
    {
        string value = "1234567890AbC";

        // create the barcode writer
        using (BarcodeWriter writer = new BarcodeWriter())
        {
            // specify that writer must generate Code39 barcode
            writer.Settings.Barcode = BarcodeType.Code39;

            // create the barcode reader
            using (BarcodeReader reader = new BarcodeReader())
            {
                // specify that reader must search for Code39 barcodes only
                reader.Settings.ScanBarcodeTypes = BarcodeType.Code39;
                // specify that reader must search for barcode with 100% confidence only
                reader.Settings.MinConfidence = 100;
                // specify that reader must use barcodes in automatic mode
                reader.Settings.AutomaticRecognition = true;
                // specify that reader must search for 1 barcode
                reader.Settings.ExpectedBarcodes = 1;

                // set the barcode value without checksum
                writer.Settings.Value = value;
                // create image with barcode without checksum
                using (VintasoftBitmap barcodeNoChecksumImage = writer.GetBarcodeAsVintasoftBitmap())
                {
                    // set the barcode value with checksum
                    writer.Settings.Value = value + GenerateChecksum(value);
                    // create image with barcode with checksum
                    using (VintasoftBitmap barcodeWithMyChecksumImage = writer.GetBarcodeAsVintasoftBitmap())
                    {
                        // specify delegate to a method for barcode verification
                        reader.Settings.VerifyBarcodeMethod = VerifyBarcodeMethod;

                        // read barcodes from barcode image without checksum,
                        // barcode reader will not find barcode
                        IBarcodeInfo[] infos = reader.ReadBarcodes(barcodeNoChecksumImage);
                        Console.WriteLine("Scan (NoChecksum):");
                        for (int i = 0; i < infos.Length; i++)
                            Console.WriteLine(infos[i].Value);

                        // read barcodes from barcode image with checksum,
                        // barcode reader will find 1 barcode
                        infos = reader.ReadBarcodes(barcodeWithMyChecksumImage);
                        Console.WriteLine("Scan (MyChecksum):");
                        for (int i = 0; i < infos.Length; i++)
                            Console.WriteLine(infos[i].Value);
                    }
                }
            }
        }
    }

    /// <summary>
    /// Generates checksum modulo 1000.
    /// </summary>
    static string GenerateChecksum(string value)
    {
        int checkSum = 0;
        for (int i = 0; i < value.Length; i++)
        {
            checkSum += ((byte)value[i]) * (i + 1);
            checkSum %= 1000;
        }
        // result - [000..999]
        return checkSum.ToString().PadLeft(3, '0');
    }

    /// <summary>
    /// Verifies the barcode during the barcode recognition process.
    /// </summary>
    static void VerifyBarcodeMethod(BarcodeReader reader, IBarcodeInfo barcodeInfo)
    {
        if (TestChecksum(barcodeInfo.Value))
            barcodeInfo.Confidence = 100;
        else
            barcodeInfo.Confidence = 0;
    }

    /// <summary>
    /// Tests checksum in barcode value.
    /// </summary>
    static bool TestChecksum(string barcodeValue)
    {
        string value = barcodeValue.Substring(0, barcodeValue.Length - 3);
        string readChecksum = barcodeValue.Substring(barcodeValue.Length - 3);
        return readChecksum == GenerateChecksum(value);
    }

}

This example shows how to remove barcodes with ReadingQuality reading quality <0.2.

VB.NET

   
''' <summary>
''' Verifies the barcode during the barcode recognition process.
''' </summary>
Private Shared Sub VerifyBarcodeMethod(reader As BarcodeReader, barcodeInfo As IBarcodeInfo)   
    If barcodeInfo.ReadingQuality < 0.2 Then   
        barcodeInfo.Confidence = 0   
    End If   
End Sub   
   
' ...
' reader.Settings.VerifyBarcodeMethod = VerifyBarcodeMethod;
' ...


/// <summary>
/// Verifies the barcode during the barcode recognition process.
/// </summary>
static void VerifyBarcodeMethod(BarcodeReader reader, IBarcodeInfo barcodeInfo)
{
    if (barcodeInfo.ReadingQuality < 0.2)
        barcodeInfo.Confidence = 0;
}

// ...
// reader.Settings.VerifyBarcodeMethod = VerifyBarcodeMethod;
// ...

Requirements

Target Platforms: .NET 7; .NET 6; .NET 5; .NET Core 3.1; .NET Framework 4.8, 4.7, 4.6, 4.5, 4.0, 3.5

Reference

ReaderSettings Class
ReaderSettings Members

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