Visual Basic与图像处理（三）

3、特殊模板

有时候利用一些特殊的模板可以达到意外的效果，利用均值滤波类似的方法，只是改变模板就可能达到特殊的效果，这里以下面一个模板为例，可以达到边缘检测的效果：

 

下面是系统的

运行界面：

特殊模板按钮对应的代码如下：

Private Sub cmdSpecialFilter_Click()

    Dim i As Integer, j As Integer

    Dim PixelValue As Long

    Dim r As Integer, g As Integer, b As Integer

    Dim GrayValue As Integer

    

    Dim Temp(2, 2) As Integer

    Dim x As Integer, y As Integer

    Dim NGrayValue As Integer

   

     '设置目标图像的高度和宽度

    DestImHeight = SourceImHeight

    DestImWidth = SourceImWidth

   

    '设置目标PictureBox的大小

    PicDest.Height = DestImHeight

    PicDest.Width = DestImWidth

   

 

    ReDim dbits(DestImHeight - 1, DestImWidth - 1, 2) As Byte '重新定义目标数组的维数

    dbits = sbits '数组的直接复制，只有数组维数完全一样才可以

   

    '图像的特殊模板滤波

    For i = 1 To SourceImHeight - 2 '边界像素不处理

        For j = 1 To SourceImWidth - 2

            NGrayValue = 0

            For x = 0 To 2

                For y = 0 To 2

                    r = sbits(i + 1 - x, j + 1 - y, 0)

                    g = sbits(i + 1 - x, j + 1 - y, 1)

                    b = sbits(i + 1 - x, j + 1 - y, 2)

              '插入图像处理的过程，对r, g, b进行处理

                    Temp(x, y) = 0.3 * r + 0.59 * g + 0.11 * b

                Next y

            Next x

            NGrayValue = Temp(0, 1) + Temp(1, 0) + Temp(2, 1) + Temp(1, 2) - 4 * Temp(1, 1)

         

        

            If NGrayValue < 0 Then NGrayValue = 0

            If NGrayValue > 255 Then NGrayValue = 255

            dbits(i, j, 0) = NGrayValue

            dbits(i, j, 1) = NGrayValue

            dbits(i, j, 2) = NGrayValue

        Next j

    Next i

   

       

   

    Dim tDBmpInfo As BITMAP

    Dim hDestBmp As Long

       

 

    hDestBmp = PicDest.Image.Handle

 

        '获得位图信息

    Call GetObject(hDestBmp, Len(tDBmpInfo), tDBmpInfo)

    ReDim ImageArray(1 To DestImWidth * 4, 1 To DestImHeight) As Byte

     

   

    For i = 1 To DestImHeight

        For j = 1 To DestImWidth

            ImageArray((j - 1) * 4 + 1, i) = dbits(i - 1, j - 1, 2)

            ImageArray((j - 1) * 4 + 2, i) = dbits(i - 1, j - 1, 1)

            ImageArray((j - 1) * 4 + 3, i) = dbits(i - 1, j - 1, 0)

        Next j

    Next i

   

'获得源图与目标图二进制位

 

Call SetBitmapBits(hDestBmp, tDBmpInfo.bmWidthBytes * tDBmpInfo.bmHeight, ImageArray(1, 1))

 

End Sub

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