VerifyBarcodeMethod Property (ReaderSettings)
In This Topic
Gets or sets method that verifies the information about barcode found by barcode reader.
Syntax
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 C#/VB.NET code shows how to generate Code 39 barcode with user-defined base 1000 cheksum, and read it using check barcode checksum in verify barcode method.
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 C#/VB.NET code shows how to remove barcodes with
reading quality<0.2.
''' <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: .NET9; .NET 8; .NET 7; .NET 6; .NET Framework 4.8, 4.7, 4.6, 4.5, 4.0, 3.5
See Also