VB.NET Barcode Reader & Scanner SDK Tutorial

• Basic Scanning: Use method Scan to extract raw barcodes' data in string array format.
• Detailed Scanning: Use method ScanInDetails to extract complete barcode metadata (BarcodeDetail, a structured object containing barcode data, location, and format details).

Dim rawDatas As String() = BarcodeScanner.Scan(
    "code128-barcode.png", BarcodeType.Code128)

Dim detailDatas As BarcodeDetail() = BarcodeScanner.ScanInDetails(
    "code128-barcode.png", BarcodeType.Code128)

Dim options As New ScanOptions(BarcodeType.DataMatrix)
Dim result As BarcodeDetail() = BarcodeScanner.Scan("C://Input//datamatrix.png", options)

Supported Custumization Options

• SetScanRegions()
  Enables scanning of specified rectangular areas within an image.
  This reduces the scanning range, accelerates processing speed, and improves recognition accuracy.
• SetMaxMultiThreadCount()
  Enables multi-threaded barcode scanning in VB.NET.
  It optimizes batch processing for Windows Forms and WPF bulk image scenarios.
• ScanSingle
  Limits the library to detect only one barcode per image.
  It significantly boosts speed when images contain single barcode.
• EnableGS1
  Enables parsing of GS1 (a universal supply chain barcode standard) data elements.
  Supports GS1 compatible barcodes: QR Code, Data Matrix, GS1-128, GS1 DataBar.
• ScanDirection
  Specifies the image scanning directions for the barcode library.
  Direct configuration reduces invalid detection and accelerates reading speed.
• StepInterval
  Defines the line spacing for barcode area search.
  It determines how many pixel lines the library scans in one step.
• ZoomRatio
  Valid range: 0.2F - 5.0F (default value = 1.0F).
  Applies zoom scaling to the source image before scanning.

• Rotation
  Returns the rotation angle of the detected barcode on the image.
• X1, Y1, X2, Y2, X3, Y3, X4, Y4
  8 coordinate properties that define the four-corner position of the barcode region.
• IsStructuredAppend
  Exclusive to QR Code and Data Matrix barcodes.
  Identifies if the barcode uses Structured Append mode (split large data across multiple barcodes).
• IsGS1Compatible
  Exclusive to QR Code, Data Matrix, and Code 128 barcodes.
  Identifies if the barcode supports GS1 standard data format.
• isMacroPDF417()
  Exclusive to PDF417 barcodes.
  Verifies if the barcode is in Macro PDF417 format.
• GetDataBytes()
  Returns the raw barcode data as a byte array.
• GetMessage() / GetMessage(Encoding enc)
  Returns barcode text using default UTF-8 encoding or a custom encoding format.

1. Prepare the target image file containing mixed barcodes (e.g. QR Code, Code 128).
2. Call the ScanInDetails method of the BarcodeScanner class.
3. Pass the image path and a generic list of target barcode types as parameters.
4. The method returns a BarcodeDetail (scanned barcode detailed information entity) array with complete barcode data.

Dim barcodeDatas As BarcodeDetail() = BarcodeScanner.ScanInDetails(
    "multiple-barcodes.png",
    New List(Of BarcodeType) From {BarcodeType.QRCode, BarcodeType.Code128}
)

• Undefined: Default value, equivalent to All.
• LeftToRight: Scans the image from left to right.
• TopToBottom: Scans the image from top to bottom.
• RightToLeft: Scans the image from right to left.
• BottomToTop: Scans the image from bottom to top.
• Horizontal: Combines LeftToRight and RightToLeft scanning.
• Vertical: Combines TopToBottom and BottomToTop scanning.
• All: Scans from all four directions (left-right, right-left, top-bottom, bottom-top).

Dim scanOps As New ScanOptions(BarcodeType.Code128)
scanOps.ScanDirection = ScanDirectionType.LeftToRight Or ScanDirectionType.TopToBottom

Step 1: Create a VB.NET method to perform a single round of barcode scanning.

Private Shared Sub ReadBarcodeSingleRound()
    ' Initialize scanning configuration
    Dim scanOps As New ScanOptions(BarcodeType.Code128)
    
    ' Configure different scanning directions (uncomment one only)
    scanOps.ScanDirection = ScanDirectionType.All
    'scanOps.ScanDirection = ScanDirectionType.Horizontal
    'scanOps.ScanDirection = ScanDirectionType.LeftToRight
    'scanOps.ScanDirection = ScanDirectionType.LeftToRight Or ScanDirectionType.TopToBottom
    
    ' Execute scanning with the configured options
    Dim scanResult As BarcodeDetail() = BarcodeScanner.Scan(
       "C:\Input\barcode-code128-demo-image.png", scanOps)
    
    ' Output scanning results
    If scanResult.Length > 0 Then
        Debug.WriteLine("Count: {scanResult.Length}")
        For Each barcode As BarcodeDetail In scanResult
            Debug.WriteLine("Message: '{barcode.GetMessage()}'")
        Next
    Else
        Debug.WriteLine("No Barcode Found.")
    End If
End Sub

Step 2: Run the scanning test 10 consecutive times and measure total execution time.

' Initialize stopwatch for performance measurement
Dim stopwatch As New Stopwatch()
stopwatch.Start()

' Repeat scanning test 10 rounds
For round As Integer = 0 To 9
    ReadBarcodeSingleRound()
Next

stopwatch.Stop()

' Calculate and display total time and average time
Dim totalTime As Single = CSng(stopwatch.ElapsedMilliseconds) / 1000.0F
Dim averageTime As Single = totalTime / 10.0F
Debug.WriteLine("Time: {totalTime:F3}s; Ave.: {averageTime:F3}s")

Step 3: Scanning Direction Performance Result Analysis

1. ScanDirectionType.All
2. ScanDirectionType.Horizontal
3. ScanDirectionType.LeftToRight
4. ScanDirectionType.LeftToRight Or ScanDirectionType.TopToBottom

ScanDirectionType.All	ScanDirectionType.LeftToRight | ScanDirectionType.TopToBottom
ScanDirectionType.LeftToRight	ScanDirectionType.Horizontal

Step 4: Core Analysis Conclusions

1. Select the scanning direction based on the barcode's rotation angle.
   Non-rotated barcodes: Use LeftToRight or RightToLeft direction.
   90-degree rotated barcodes: Use TopToBottom or BottomToTop direction.
2. More scanning directions result in longer processing time.
   Example: Horizontal (2 directions) is slower than LeftToRight (1 direction).
3. Most processing time is spent on candidate barcode verification.
4. Time differences between multi-direction modes are relatively small.
   Example: 2-direction vs 4-direction modes show minimal time gap.

StepInterval Configuration in ScanOptions

• StepInterval: Defines the scanning line spacing.
• It determines how many pixel lines the library skips between each scan pass.
• Minimum value: 1 (scans every single pixel row).
• Default value: 5 (scans one line, then skips the next 4 lines).

' Initialize ScanOptions for Code 128 barcode scanning
Dim scanOps As New ScanOptions(BarcodeType.Code128)

' Set scanning direction
scanOps.ScanDirection = ScanDirectionType.LeftToRight

' Set StepInterval value (uncomment one mode to test)
scanOps.StepInterval = 5   ' Default value
'scanOps.StepInterval = 1  ' Scan all lines (highest accuracy)
'scanOps.StepInterval = 10 ' Larger interval (faster speed)
'scanOps.StepInterval = 83 ' Maximum test interval

StepInterval = 1	StepInterval = 5
StepInterval = 10	StepInterval = 83

Test Result Analysis

1. Speed vs Interval Relationship
   • A larger StepInterval value reduces scanning time.
   • Example: StepInterval=1 (0.257s) vs StepInterval=5 (0.151s).
   • Fewer lines to check directly improves processing speed.
2. Detection Risk of Large Intervals
   • An excessively large interval may skip the barcode completely.
   • This causes no barcode detected errors.
   • Risk depends on barcode height and vertical position.
3. Failure Example
   • In the demo image, StepInterval = 83 prevents barcode detection.
   • The library skips all lines containing barcode pixels.

• Scan and parse barcode with Unicode text using C#
• Scan and parse barcode with GS1 text message using C#
• Scan and parse 2d barcode with structured append mode using C#

1. Create a ScanOptions instance and define the target barcode format (QR Code).
2. Call SetMaxMultiThreadCount() to set the maximum thread count.
3. Pass an array of image file paths to the BarcodeScanner.Scan() method with scan options applied.
4. Traverse the BarcodeDetail (barcode detailed information entity) array to process scanning results.

' Initialize scanning configuration with target barcode type
Dim scanOptions As New ScanOptions(BarcodeType.QRCode)

' Set maximum multi-threading count (3 concurrent threads)
' Value must be non-negative
' 0 = disable multi-threading (default)
' >0 = enable multi-threaded scanning
scanOptions.SetMaxMultiThreadCount(3)

' Define batch image files array
Dim imageFiles As String() = {
    "SourceImage01.png",
    "SourceImage02.png",
    "SourceImage03.png"
}

' Execute multi-threaded batch scanning
Dim scanResults As BarcodeDetail() = BarcodeScanner.Scan(imageFiles, scanOptions)

' Process and parse all scanning results
For Each barcodeObj As BarcodeDetail In scanResults
    ' Process barcode data / display results in Windows Forms/WPF UI
Next