VB.NETでOpenCV

python C#でopencvの例が山ほど上がっているが
vb.netが見当たらないのでアップしてみた

1．事前準備
　vbのフォームアプリを作成
　giuhubでOpenCvSharpと検索
　OpenCvSharp4.Windowsと
　OenCvSharp4.Extensionsをインストール
　注意：　OpenCvSharp4でなく　OpenCvSharp4.Windows

2．ネットで検索するとpythonもC#もwhile文での取り込みで
　なぜかvb.netでCv2.WaitKey()が利かない

　よってtimerで作成する事にした

3．importsの定義

Imports OpenCvSharp
Imports OpenCvSharp.Extensions

4．フォーム共通エリアでキャプチャーとマットの定義
Dim capture As VideoCapture = Nothing
Private flame As Mat = Nothing

5．ピクチャ－ボックスの初期化とサイズ
‘PictureBoxのサイズに合わせて表示
PictureBox1.SizeMode = PictureBoxSizeMode.Zoom
PictureBox2.SizeMode = PictureBoxSizeMode.Zoom
PictureBox1.Image = Nothing
PictureBox2.Image = Nothing

6．スタートボタン
VideoCaptureのインスタンスの作成

capture = New VideoCapture()
capture.Open(0)

If capture.IsOpened() = False Then
MsgBox(“capture initialization failed”, vbInformation)
End If

タイマースタート
Timer1.Interval = 30
Timer1.Start()

7．タイマーイベント

flame = New Mat()
capture.Read(flame)
If flame.Empty() Then
Exit Sub
End If
If flame.Size().Width > 0 Then
‘PictureBoxに表示　MatをBitMapに変換 PictureBox1.Image = BitmapConverter.ToBitmap(flame)
End If

8．ボタン2でキャプチャー

If flame Is Nothing Then Return End If
‘//PictureBoxに表示　MatをBitMapに変換
PictureBox2.Image = BitmapConverter.ToBitmap(flame)

9．ボタン3で終わり

Timer1.Stop()
capture.Dispose()
PictureBox1.Image = Nothing

10．全ソース

Imports OpenCvSharp
Imports OpenCvSharp.Extensions
Public Class Form1
    Dim capture As VideoCapture = Nothing
    Private flame As Mat = Nothing

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'PictureBoxのサイズに合わせて表示
        PictureBox1.SizeMode = PictureBoxSizeMode.Zoom
        PictureBox2.SizeMode = PictureBoxSizeMode.Zoom
        PictureBox1.Image = Nothing
        PictureBox2.Image = Nothing

    End Sub

    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        flame = New Mat()
        capture.Read(flame)
        If flame.Empty() Then
            Exit Sub
        End If
        If flame.Size().Width > 0 Then

            'PictureBoxに表示　MatをBitMapに変換
            PictureBox1.Image = BitmapConverter.ToBitmap(flame)
        End If
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        capture = New VideoCapture()
        capture.Open(0)
        If capture.IsOpened() = False Then
            MsgBox("capture initialization failed", vbInformation)
        End If

        Timer1.Interval = 30
        Timer1.Start()
    End Sub
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        If flame Is Nothing Then

            Return
        End If
        '//PictureBoxに表示　MatをBitMapに変換
        PictureBox2.Image = BitmapConverter.ToBitmap(flame)
    End Sub

    Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
        Timer1.Stop()
        capture.Dispose()
        PictureBox1.Image = Nothing

    End Sub

サンプル通りだと以下になるがあまりwhile文はおすすめできない
かつ
cv2.wait()がきかない

Imports OpenCvSharp
Imports OpenCvSharp.Extensions
Public Class Form1
    Private flame As Mat

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        'PictureBoxのサイズに合わせて表示
        PictureBox1.SizeMode = PictureBoxSizeMode.Zoom
        PictureBox2.SizeMode = PictureBoxSizeMode.Zoom
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim capture As VideoCapture = New VideoCapture()

        capture.Open(0)
        If capture.IsOpened() = False Then

            MsgBox("capture initialization failed", vbInformation)
        End If
        '画像取得用のMatを作成
        flame = New Mat()


        Do While True

            Try
                capture.Read(flame)
                If flame.Empty() Then
                    Exit Do
                End If
                If flame.Size().Width > 0 Then

                    'PictureBoxに表示　MatをBitMapに変換
                    PictureBox1.Image = BitmapConverter.ToBitmap(flame)
                End If

                Dim key As Integer = Cv2.WaitKey()

                If IsDisposed Then

                    Exit Do

                End If

            Catch ex As Exception
                Exit Do
            End Try

        Loop
        capture.Dispose()
        PictureBox1.Image = Nothing
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        If flame Is Nothing Then

            Return
        End If
        '//PictureBoxに表示　MatをBitMapに変換
        PictureBox2.Image = BitmapConverter.ToBitmap(flame)
    End Sub
End Class