图像处理.水平sobel Vb 6.0中的溢出

Question

我在Vb 6.0中实现了水平sobel检测器，但在（grand）值中出现了"Overflow"错误，这是我编写的sobel函数：

Public Sub HorSobel()
Dim Op_X(-1 To 1, -1 To 1) As Integer, Op_Y(-1 To 1, -1 To 1) As Integer
Dim X As Integer, Y As Integer, i As Integer, J As Integer
'Pic5.Cls
Dim Grand As Double
Grad = 0
Op_X(-1, -1) = -1: Op_X(0, -1) = -2: Op_X(1, -1) = -1
Op_X(-1, 0) = 0: Op_X(0, 0) = 0: Op_X(1, 0) = 0
Op_X(-1, 1) = 1: Op_X(0, 1) = 2: Op_X(1, 1) = 1

For Y = 0 To Pic1.Height - 1
    For X = 0 To Pic1.Width - 1
        GradX = 0: GradY = 0: Grad = 0
        If X = 0 Or Y = 0 Or X = Pic1.Width - 1 Or Y = Pic1.Height - 1 Then
            Grad = 0
        Else
            For i = -1 To 1
                For J = -1 To 1
                PixelValue = GetPixel(Pic5.hdc, X + i, Y + J)
                GradX = GradX + (PixelValue * Op_X(i, J))
                Next J
            Next i
            Grad = Round(Sqr(Abs(GradX * GradX)))
        End If
        If Grad <= 0 Then Grad = 0: If Grad >= 255 Then Grad = 255
        SetPixel Pic6.hdc, X, Y, RGB(Grad, Grad, Grad)
        'Pic5.Refresh
    Next X
Next Y
Pic6.Refresh

结束子

Answer 1

您尚未在提供的代码中声明以下变量：

• Grad
• GradX
• GradY
• PixelValue

如果您将它们声明为Long或Integer，那么这可能就是您出现Overflow错误的原因。