Determines that this image is a blank image.
Visual Basic |
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Public Function AcquiredImages_IsBlank( _ ByVal index As Long, _ ByVal maxNoiseLevel As Single, _ ByRef currentNoiseLevel As Single _ ) As Boolean |
Private VSTwain1 As New VintaSoftTwain() ''' <summary> ''' Scans images asynchronously. ''' </summary> Private Sub StartScan() ' open the device manager If Not VSTwain1.DeviceManager_Open() Then Console.WriteLine(VSTwain1.errorString) Exit Sub End If ' select device using standard device selection dialog VSTwain1.DeviceManager_ShowDefaultDeviceSelectionDialog() ' specify that device UI must be shown VSTwain1.Device_ShowUI = True ' subscribe to the device events AddHandler VSTwain1.DeviceImageAcquired, AddressOf VSTwain1_ImageAcquired AddHandler VSTwain1.DeviceScanCompleted, AddressOf VSTwain1_ScanCompleted AddHandler VSTwain1.DeviceScanFailed, AddressOf VSTwain1_ScanFailed AddHandler VSTwain1.DeviceScanCanceled, AddressOf VSTwain1_ScanCanceled ' acquire images asynchronously VSTwain1.Device_AcquireImage() End Sub Private Sub VSTwain1_ImageAcquired() ' get index of acquired image Dim imageIndex As Integer = VSTwain1.AcquiredImages_Count - 1 Dim currentNoiseLevel As Single ' if image is blank If VSTwain1.AcquiredImages_IsBlank(imageIndex, 0.01, currentNoiseLevel) Then Console.WriteLine("Image is blank.") Else If currentNoiseLevel = 100 Then Console.WriteLine("Image is not blank. " + VSTwain1.errorString) Else Console.WriteLine("Image is not blank. Noise level is " + Str(currentNoiseLevel) + "%") End If End If End Sub Private Sub VSTwain1_ScanCompleted() Console.WriteLine("Scan is completed.") End Sub Private Sub VSTwain1_ScanFailed(errorString As String) Console.WriteLine(String.Format("Scan is failed: {0}.", errorString)) End Sub Private Sub VSTwain1_ScanCanceled() Console.WriteLine("Scan is canceled.") End Sub