ByteScout Barcode Reader SDK - VB.NET - Read Barcode From Live Video Cam (WPF) - ByteScout

ByteScout Barcode Reader SDK – VB.NET – Read Barcode From Live Video Cam (WPF)

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How to read barcode from live video cam (wpf) in VB.NET using ByteScout BarCode Reader SDK

How to read barcode from live video cam (wpf) in VB.NET

Learn how to read barcode from live video cam (wpf) in VB.NET with this source code sample. ByteScout BarCode Reader SDK is the SDK for barcode decoding. Can read all popular types from Code 128, GS1, UPC and Code 39 to QR Code, Datamatrix, PDF417. Images, pdf, TIF images and live web camera are supported as input. Designed to handle documents with noise and defects. Includes optional splitter and merger for pdf and tiff based on barcodes. Batch mode is optimized for high performance with multiple threads. Decoded values can be exported to XML, JSON, CSV or into custom data format and you can use it to read barcode from live video cam (wpf) with VB.NET.

Fast application programming interfaces of ByteScout BarCode Reader SDK for VB.NET plus the instruction and the code below will help you quickly learn how to read barcode from live video cam (wpf). In order to implement the functionality, you should copy and paste this code for VB.NET below into your code editor with your app, compile and run your application. Use of ByteScout BarCode Reader SDK in VB.NET is also explained in the documentation included along with the product.

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Class Application ' Application-level events, such as Startup, Exit, and DispatcherUnhandledException ' can be handled in this file. End Class

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Imports System.ComponentModel Imports System.Drawing Imports System.Drawing.Imaging Imports System.IO Imports System.Reflection Imports System.Threading Imports System.Windows.Threading Imports Bytescout.BarCodeReader Imports TouchlessLib Public Class MainWindow ' Touchless lib manager object (to use it you should have TouchlessLib.dll and WebCamLib.dll) Private _touchlessMgr As TouchlessMgr ' USED IN POPUP MODE ONLY (see ShowScanPopup() method) ' Close or not on the first barcode found ' (results are saved in m_foundBarcodes) Public Property CloseOnFirstBarcodeFound As Boolean = False ' Indicates if the form is closed Public Property IsClosed As Boolean = False ' Background processing object Private _backgroundWorker As New BackgroundWorker() ' Barcode type to scan Private _barcodeTypeToFind As New BarcodeTypeSelector() ' Array with decoded barcodes from the last scanning session. Public Property FoundBarcodes As FoundBarcode() = Nothing ' Scanning delay (ms); default is to scan every 800 ms. Const ScanDelay As Integer = 800 ' Internal varaible to indicate the status. Public Shared Status As Boolean = True Public Sub New() InitializeComponent() lblScanning.Visibility = Visibility.Collapsed _backgroundWorker.WorkerSupportsCancellation = True AddHandler _backgroundWorker.DoWork, AddressOf BackgroundWorker_DoWork AddHandler _backgroundWorker.RunWorkerCompleted, AddressOf BackgroundWorker_RunWorkerCompleted End Sub Delegate Sub MyDelegate() ' Searches for barcodes in bitmap object Private Function FindBarcodes(bitmap As Bitmap) As FoundBarcode() Dim reader As New Bytescout.BarCodeReader.Reader() Try reader.RegistrationName = "demo" reader.RegistrationKey = "demo" Me.Dispatcher.Invoke(DispatcherPriority.Normal, Sub() UpdateBarcodeTypeToFindFromCombobox()) reader.BarcodeTypesToFind = _barcodeTypeToFind ' ----------------------------------------------------------------------- ' NOTE: We can read barcodes from specific page to increase performance . ' For sample please refer to "Decoding barcodes from PDF by pages" program. ' ----------------------------------------------------------------------- Dim result As FoundBarcode() = reader.ReadFrom(bitmap) Dim timeNow As String = String.Format("{0:HH:mm:ss:tt}", DateTime.Now) Dispatcher.Invoke(DispatcherPriority.Normal, Sub() If result IsNot Nothing And result.Length > 0 Then textAreaBarcodes.SelectAll() textAreaBarcodes.Selection.Text = Environment.NewLine & "Time: " & timeNow & Environment.NewLine ' insert barcodes into text box For Each barcode As FoundBarcode In result ' make a sound that we found the barcode Console.Beep() 'form the string with barcode value Dim barcodeValue As String = String.Format("Found: {0} {1}" & Environment.NewLine, barcode.Type, barcode.Value) ' add barcode to the text area output textAreaBarcodes.AppendText(barcodeValue & Environment.NewLine) ' add barcode to the list of saved barcodes lblFoundBarcodes.Content = String.Format("Found {0} barcodes:", result.Length) Next End If ' make "Scanning..." label flicker If lblScanning.Visibility = Visibility.Collapsed Then lblScanning.Visibility = Visibility.Visible Else lblScanning.Visibility = Visibility.Collapsed End If End Sub) ' return found barcodes Return result Finally reader.Dispose() End Try End Function ' Updates barcode type filter according with combobox selection Private Sub UpdateBarcodeTypeToFindFromCombobox() Dim selectedItemText As String = cbBarCodeType.Text If String.IsNullOrEmpty(selectedItemText) Then Throw New Exception("Empty barcode type selection.") _barcodeTypeToFind.Reset() ' Iterate through BarcodeTypeSelector bool properties ' and enable property by barcode name selected in the combobox For Each propertyInfo As PropertyInfo In GetType(BarcodeTypeSelector).GetProperties() ' Skip readonly properties If Not propertyInfo.CanWrite Then Continue For End If If propertyInfo.Name = selectedItemText Then propertyInfo.SetValue(_barcodeTypeToFind, True, Nothing) End If Next End Sub Private Sub Window_Loaded(sender As System.Object, e As RoutedEventArgs) Handles MyBase.Loaded 'Populate barcode types into the combobox PopulateBarcodeTypesCombobox() InitCamera() StartDecoding() End Sub Private Sub InitCamera() Try ' Create Touchless lib manager to work with video camera _touchlessMgr = New TouchlessMgr() ' Iterate through available video camera devices For Each camera As Camera In _touchlessMgr.Cameras ' Add to list of available camera devices cbCamera.Items.Add(camera) Next ' Select first available camera cbCamera.SelectedItem = _touchlessMgr.Cameras(0) ' Setting default image dimensions; see also camera selection event. _touchlessMgr.Cameras(0).CaptureWidth = Integer.Parse(tbCameraWidth.Text) _touchlessMgr.Cameras(0).CaptureHeight = Integer.Parse(tbCameraHeight.Text) Catch exception As Exception MessageBox.Show("No video camera available. Please connect camera." + Environment.NewLine + exception.Message) End Try End Sub Sub StartDecoding() UpdateCameraSelection() ' Clear the text box output Dim txt As New TextRange(textAreaBarcodes.Document.ContentStart, textAreaBarcodes.Document.ContentEnd) txt.Text = "" ' Clean list of found barcodes FoundBarcodes = Nothing ' Check camera selected If cbCamera.SelectedIndex <> -1 Then ' Set status Status = True ' Update UI buttons btnStart.IsEnabled = False btnStop.IsEnabled = True cbBarCodeType.IsEnabled = False cbCamera.IsEnabled = False tbCameraHeight.IsEnabled = False tbCameraWidth.IsEnabled = False lblScanning.Content = "Scanning..." ' Start the decoding thread _backgroundWorker.RunWorkerAsync(CloseOnFirstBarcodeFound) Else MessageBox.Show("Please select camera") End If End Sub Private Sub Window_Closing(sender As System.Object, e As CancelEventArgs) Handles MyBase.Closing Deinitialize() End Sub Private Sub cbCamera_SelectionChanged(sender As System.Object, e As SelectionChangedEventArgs) Handles cbCamera.SelectionChanged UpdateCameraSelection() End Sub Private Sub btnStart_Click(sender As System.Object, e As RoutedEventArgs) Handles btnStart.Click StartDecoding() End Sub Private Sub btnStop_Click(sender As System.Object, e As RoutedEventArgs) Handles btnStop.Click StopDecoding() End Sub Private Sub btnExit_Click(sender As System.Object, e As RoutedEventArgs) Handles btnExit.Click Close() End Sub Private Sub btnTryPopup_Click(sender As System.Object, e As RoutedEventArgs) Handles btnTryPopup.Click ' Stop scan if any StopDecoding() ' Deinit the current camera DeinitCamera() ShowScanPopup() ' Reinit current camera InitCamera() End Sub Sub BackgroundWorker_DoWork(sender As Object, e As DoWorkEventArgs) Dim worker As BackgroundWorker = sender Dim closeOnFirstBarcode As Boolean = e.Argument While True ' Work till user canceled the scan If worker.CancellationPending Then e.Cancel = True Return End If ' Get current frame bitmap from camera using Touchless lib Dim bitmap As Bitmap = _touchlessMgr.CurrentCamera.GetCurrentImage() ' Search barcodes Dim result As FoundBarcode() = Nothing If bitmap IsNot Nothing Then result = FindBarcodes(bitmap) ' Check if we need to stop on first barcode found If closeOnFirstBarcode AndAlso result IsNot Nothing AndAlso result.Length > 0 Then e.Result = result Return End If ' Wait a little to lower CPU load Thread.Sleep(ScanDelay) End While End Sub Sub BackgroundWorker_RunWorkerCompleted(sender As Object, e As RunWorkerCompletedEventArgs) ' Clear last results FoundBarcodes = Nothing If e.Cancelled Then lblScanning.Content = "Canceled" ElseIf e.Error IsNot Nothing Then lblScanning.Content = "Error: " & e.Error.Message Else lblScanning.Content = "Done." FoundBarcodes = e.Result End If StopDecoding() End Sub ' Update picture box with the latest frame from video camera Sub CurrentCamera_OnImageCaptured(sender As Object, e As CameraEventArgs) ' You can change image dimensions if needed '_touchlessMgr.CurrentCamera.CaptureWidth = 320 '_touchlessMgr.CurrentCamera.CaptureHeight = 240 Dispatcher.Invoke(DispatcherPriority.Normal, Sub() If _touchlessMgr IsNot Nothing Then pictureVideoPreview.BeginInit() Dim imageSource As BitmapImage = BitmapToImageSource(_touchlessMgr.CurrentCamera.GetCurrentImage(), ImageFormat.Png) Dim st = New ScaleTransform() st.ScaleX = 320.0F / imageSource.PixelWidth st.ScaleY = 240.0F / imageSource.PixelHeight pictureVideoPreview.Source = New TransformedBitmap(imageSource, st) pictureVideoPreview.EndInit() pictureVideoPreview.UpdateLayout() End If End Sub) End Sub Function BitmapToImageSource(bitmap As Bitmap, imageFormat As ImageFormat) As BitmapImage Using memoryStream As New MemoryStream bitmap.Save(memoryStream, imageFormat) memoryStream.Position = 0 Dim bitmapImage As New BitmapImage() bitmapImage.BeginInit() bitmapImage.StreamSource = memoryStream bitmapImage.CacheOption = BitmapCacheOption.OnLoad bitmapImage.EndInit() Return bitmapImage End Using End Function Sub StopDecoding() _backgroundWorker.CancelAsync() ' Update UI elements lblScanning.Visibility = Visibility.Collapsed ' Change working status Status = False btnStart.IsEnabled = True btnStop.IsEnabled = False cbBarCodeType.IsEnabled = True cbCamera.IsEnabled = True tbCameraHeight.IsEnabled = True tbCameraWidth.IsEnabled = True If CloseOnFirstBarcodeFound Then If FoundBarcodes IsNot Nothing AndAlso FoundBarcodes.Length > 0 Then Close() End If End If End Sub Sub UpdateCameraSelection() If cbCamera.Items.Count > 0 And cbCamera.SelectedIndex > -1 Then If _touchlessMgr.CurrentCamera IsNot Nothing Then RemoveHandler _touchlessMgr.CurrentCamera.OnImageCaptured, AddressOf CurrentCamera_OnImageCaptured End If _touchlessMgr.CurrentCamera = Nothing Dim currentCamera As Camera = _touchlessMgr.Cameras(cbCamera.SelectedIndex) ' Setting camera output image dimensions currentCamera.CaptureWidth = Integer.Parse(tbCameraWidth.Text) currentCamera.CaptureHeight = Integer.Parse(tbCameraHeight.Text) _touchlessMgr.CurrentCamera = currentCamera AddHandler _touchlessMgr.CurrentCamera.OnImageCaptured, AddressOf CurrentCamera_OnImageCaptured End If End Sub Sub PopulateBarcodeTypesCombobox() cbBarCodeType.Items.Clear() Dim items As New List(Of String)() For Each propertyInfo As PropertyInfo In GetType(BarcodeTypeSelector).GetProperties() ' Skip readonly properties If Not propertyInfo.CanWrite Then Continue For End If items.Add(propertyInfo.Name) Next items.Sort() cbBarCodeType.ItemsSource = items ' Select first item in combobox (first is "Find All") cbBarCodeType.SelectedItem = cbBarCodeType.Items(0) End Sub Sub Deinitialize() ' Cancel decoding thread _backgroundWorker.CancelAsync() ' Deinit camera DeinitCamera() ' Mark as closed _isClosed = True End Sub Sub DeinitCamera() If _touchlessMgr IsNot Nothing Then RemoveHandler _touchlessMgr.CurrentCamera.OnImageCaptured, AddressOf CurrentCamera_OnImageCaptured _touchlessMgr.CurrentCamera = Nothing End If If cbCamera.SelectedItem IsNot Nothing Then cbCamera.SelectedItem = Nothing End If cbCamera.Items.Clear() _touchlessMgr = Nothing Thread.Sleep(500) End Sub Sub ShowScanPopup() ' Create another MainWindow instance to scan barcodes Dim popup As New MainWindow() ' Set new popup position shifted by 20 pixels popup.Left = Left + 20 popup.Top = Top + 20 ' Set the new popup window to close on first found barcode popup.CloseOnFirstBarcodeFound = True ' Hide btnTryPopup button popup.btnTryPopup.Visibility = Visibility.Hidden popup.btnStop.Visibility = Visibility.Hidden popup.btnStart.Visibility = Visibility.Hidden ' Set the popup title popup.Title = "POPUP DIALOG - ONE-TIME SCAN" ' Show the dialog popup.Show() ' Now wait while the popup is closed (it will be closed on barcode found or canceled) While Not popup.IsClosed ' HACK: Simulate "DoEvents" Dispatcher.Invoke(DispatcherPriority.Background, Sub() Thread.Sleep(20)) Thread.Sleep(20) End While ' Checking if one-time scan dialog found barcodes If popup.FoundBarcodes IsNot Nothing AndAlso popup.FoundBarcodes.Length > 0 Then MessageBox.Show("Popup scan found the barcode: " & Environment.NewLine & popup.FoundBarcodes(0).Value, "POPUP RESULT") Else MessageBox.Show("Popup canceled. Returning to the main window") End If ' Close the dialog popup.Close() End Sub End Class

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