WIA (Windows Image Acquisition) WebCam Sample Project

[gigemboy]

Here's a sample VB.NET 2003 project I made that shows how to capture snapshots from a webcam using WIA (Windows Image Acquisition). It detects the available device (tested with a Logitec Webcam), and allows you to grab an image. Being that it is a WIA Sample project, you have to use a WIA enabled device (usually if the device shows up in "Scanners & Cameras" in control panel, it should be WIA enabled).

The ability to use WIA, you first need to have the WIA Automation Layer, provided in "wiaaut.dll", registered. If you need this, you can download it from Microsoft here: http://www.microsoft.com/downloads/d...DisplayLang=en
You then need to add a reference to the dll if you wish to use it in a project of yours. It should already be done so in the sample project download at the end.

***Note - WIA 2.0 is only supported in Windows XP SP1 or later.

Sample project code for the procedure to get the available devices (see full code in zip file):

Private Sub GetDevice()
        Dim MyDevice As WIA.Device
        Dim MyDialog As New WIA.CommonDialogClass
        Try
            'shows selectdevice dialog, if only one device, It automatically selects the device
            '(not tested with two or more devices)
            '**Note - Device Type checks for VideoDeviceType, for webcams, in this sample
            MyDevice = MyDialog.ShowSelectDevice(WIA.WiaDeviceType.VideoDeviceType, False, True)
            If Not MyDevice Is Nothing Then
                'loops through device properties, only gets the ones we want to display
                For Each prop As WIA.Property In MyDevice.Properties
                    Select Case prop.Name
                        Case "Manufacturer"
                            lblMfg.Text = prop.Value.ToString
                        Case "Description"
                            lblDesc.Text = prop.Value.ToString
                        Case "Name"
                            lblName.Text = prop.Value.ToString
                        Case "WIA Version"
                            lblWIA.Text = prop.Value.ToString
                        Case "Driver Version"
                            lblDriver.Text = prop.Value.ToString
                    End Select
                Next
                'sets MyDevice form level selected device
                SelectedDevice = MyDevice
            Else
                lblName.Text = "No WIA Devices Found!"
            End If
        Catch ex As System.Exception
            MessageBox.Show("Problem! " & ex.Message, _
                  "Problem Loading Device", MessageBoxButtons.OK, MessageBoxIcon.Warning, _
                  MessageBoxDefaultButton.Button1, MessageBoxOptions.DefaultDesktopOnly)
            lblName.Text = "No WIA Devices Found!"
        End Try
    End Sub

Sample project code to grab the picture from the device (see full code in zip file):

Private Sub btnGrab_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGrab.Click
        Dim item As WIA.Item
        Try
            'executes the device's TakePicture command
            item = SelectedDevice.ExecuteCommand(WIA.CommandID.wiaCommandTakePicture)
        Catch ex As System.Exception
            MessageBox.Show("Problem Taking Picture. Please make sure that the camera" & _
                          "is plugged in and is not in use by another application. " & vbCrLf & _
                          "Extra Info:" & ex.Message, "Problem Grabbing Picture", _
                          MessageBoxButtons.OK, MessageBoxIcon.Warning, MessageBoxDefaultButton.Button1, _
                          MessageBoxOptions.DefaultDesktopOnly)
            Exit Sub
        End Try
        Dim jpegGuid As String
        'retrieves jpegKey from registry, used in getting JPEG format of pic, can be hard coded
        Dim jpegKey As Microsoft.Win32.RegistryKey = _
                 Microsoft.Win32.Registry.ClassesRoot.OpenSubKey("" & _
                 "CLSID\{D2923B86-15F1-46FF-A19A-DE825F919576}\SupportedExtension\.jpg")
        jpegGuid = CType(jpegKey.GetValue("FormatGUID"), String)
        'loops through available formats for the captured item, looking for the JPG format
        For Each format As String In item.Formats
            If (format = jpegGuid) Then
                'transfers image to an imagefile object
                Dim imagefile As WIA.ImageFile = CType(item.Transfer(format), WIA.ImageFile)
                Dim Counter As Integer 'counter in loop appended to filename 
                Dim LoopAgain As Boolean = True
                'searches directory, gets next available picture name
                Do Until LoopAgain = False
                    Dim Filename As String = SavePath & "\" & txtPrefix.Text & Counter.ToString & ".jpg"
                    'if file doesnt exist, save the file
                    If Not System.IO.File.Exists(Filename) Then
                        SavedFilePath = Filename
                        imagefile.SaveFile(Filename) 'saves file to disk
                        lblCapName.Text = FormatPath(Filename)
                        lblImageName.Text = txtPrefix.Text & Counter.ToString & ".jpg"
                        picCap.Image = Image.FromFile(Filename) 'loads captured file to picturebox
                        LoopAgain = False
                    End If
                    Counter = Counter + 1
                Loop
            End If
        Next
        If grpSaved.Enabled = False Then
            grpSaved.Enabled = True
        End If
End Sub

The code automatically saves the picture to a new filename, so you can grab multiple captures one after another.

The project so far is only for webcams, but can be extended to do similar things with digital cameras, camcorders, basically any supported WIA device.