VB.NET使用EmguCV捕获摄像头照片遇重载解析错误求助

错误原因 #

报错行是代码第25行：Dim bitmapFrame As Bitmap = New Bitmap(imageFrame)。EmguCV的Image(Of Bgr, Byte)属于自定义封装类型，并非.NET原生的System.Drawing.Image或可直接适配Bitmap构造函数的类型，因此编译器找不到匹配的重载方法，触发BC30518错误。

解决方法 #

直接使用EmguCV的Image(Of TColor, TDepth)对象自带的Bitmap属性，就能直接获取对应的.NET Bitmap实例，无需手动调用Bitmap构造函数：

修改这一行代码：

Dim bitmapFrame As Bitmap = imageFrame.Bitmap

修正后的完整代码 #

Imports Emgu.CV
Imports Emgu.CV.Structure
Imports Emgu.CV.CvEnum
Imports System.Drawing
Imports System.Globalization

Public Class WebCamForm
Private capture As VideoCapture
Public ReadOnly Property InstalledUICulture As CultureInfo

Private Sub PhotoCaptureForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    ' Initialize the Capture object for webcam access
    capture = New VideoCapture()
End Sub

Private Sub Button_CapturePhoto_Click(sender As Object, e As EventArgs) Handles Button_CapturePhoto.Click
    ' Capture a frame from the webcam
    Dim currentFrame As Mat = capture.QueryFrame()

    If currentFrame IsNot Nothing Then
        ' Convert the Mat object to an Image(Of Bgr, Byte) object
        Dim imageFrame As Image(Of Bgr, Byte) = currentFrame.ToImage(Of Bgr, Byte)()

        ' Convert the Image(Of Bgr, Byte) object to a Bitmap object
        Dim bitmapFrame As Bitmap = imageFrame.Bitmap

        ' Display the captured image in the PictureBox
        PictureBox1.Image = bitmapFrame

        ' Save the captured image to a file
        Dim fileName As String = "captured_photo.jpg"
        bitmapFrame.Save(fileName)
    End If
End Sub

Private Sub PhotoCaptureForm_FormClosing(sender As Object, e As FormClosingEventArgs) Handles Me.FormClosing
    ' Release the resources associated with the Capture object
    If capture IsNot Nothing Then
        capture.Dispose()
    End If
End Sub

End Class

额外说明 #

EmguCV的Image类已经封装了与.NET绘图对象的转换接口，直接使用Bitmap属性是最简洁且安全的方式，既避免了类型不匹配的问题，也能保证资源正确处理。

内容的提问来源于stack exchange，提问作者ASTRA