原先是一个 VB6.0的 验证码识别源码，修改成了 VB2008下的。代码很初级，仅供参考。
验证码识别的基本思路：获取图片→二值化→去噪→分割匹配→识别
获取验证码图片并显示在PictureBox上 1 Dim WR As WebRequest = WebRequest.Create(TxtUrl.Text) 2 Dim RESP As WebResponse = WR.GetResponse 3 Dim BMP As New Bitmap(RESP.GetResponseStream) 4 PictureBox1.Image = BMP
二值化 1 Public Sub Binarization() ' 二值化 2 Dim NumS As String = "" 3 ' Dim pix(0, 0) As Boolean 4 ReDim pix(PictureBox1.Width - 1 , PictureBox1.Height - 1 ) 5 6 Dim iy As Integer 7 Dim ix As Integer 8 9 Dim BMP As Bitmap = New Bitmap(PictureBox1.Image) 10 11 Dim Pixel As Color 12 13 CG = TxtG.Text : CR = TxtR.Text : CB = TxtB.Text 14 For iy = 0 To BMP.Height - 1 15 For ix = 0 To BMP.Width - 1 16 Pixel = BMP.GetPixel(ix, iy) 17 If Pixel.G <> CG Or Pixel.R <> CR Or Pixel.B <> CB Then 18 pix(ix, iy) = False 19 Else 20 pix(ix, iy) = True 21 End If 22 Next 23 Next 24 25 Dim str As String = "" 26 For iy = 0 To pix.GetUpperBound( 1 ) ' UBound(pix(, ), 2) 27 For ix = 0 To pix.GetUpperBound( 0 ) ' UBound(pix(), 1) 28 If pix(ix, iy) Then 29 str = str & " ■ " 30 Else 31 str = str & " □ " 32 End If 33 Next 34 str = str & vbCrLf 35 Next 36 37 TxtChar.Text = str 38 End Sub
分割验证码 1 Public Sub SplitCheckCode() ' 分割验证码 2 Dim i, j, k, p As Integer 3 Dim bL, bR As Boolean 4 ' 第一步, 找出纵向分割界线 5 vCode( 0 ).Left = 0 6 For i = 0 To Pix.GetUpperBound( 0 ) 7 For j = 0 To Pix.GetUpperBound( 1 ) 8 If Pix(i, j) = False Then Exit For ' 检验是否整列均为■ 9 Next 10 If j = Pix.GetUpperBound( 1 ) + 1 Then 11 If i > Pix.GetLowerBound( 0 ) Then 12 For k = 0 To Pix.GetUpperBound( 1 ) 13 If Pix(i - 1 , k) = False Then Exit For ' 检验是否整列均为■ 14 Next 15 If k < Pix.GetUpperBound( 1 ) + 1 Then bL = True 16 End If 17 If i < Pix.GetUpperBound( 0 ) Then 18 For k = 0 To Pix.GetUpperBound( 1 ) 19 If Pix(i + 1 , k) = False Then Exit For ' 检验是否整列均为■ 20 Next 21 If k < Pix.GetUpperBound( 1 ) + 1 Then bR = True 22 End If 23 End If 24 If (bL Or bR) Then 25 p = p + 1 : bL = False : bR = False 26 Select Case p 27 Case 1 : vCode( 0 ).Right = i - 1 28 Case 2 : vCode( 1 ).Left = i + 1 29 Case 3 : vCode( 1 ).Right = i - 1 30 Case 4 : vCode( 2 ).Left = i + 1 31 Case 5 : vCode( 2 ).Right = i - 1 32 Case 6 : vCode( 3 ).Left = i + 1 33 Case 7 : vCode( 3 ).Right = i - 1 34 End Select 35 End If 36 Next 37 For k = 0 To 3 38 vCode(k).Top = 0 : vCode(k).Bottom = 9 : vCode(k).CodeChar = "" 39 Next 40 ' 第二步, 将所有字符转为特征码 41 For k = 0 To 3 42 For i = vCode(k).Left To vCode(k).Right 43 For j = vCode(k).Top To vCode(k).Bottom 44 If Pix(i, j) Then p = 0 Else p = 1 45 vCode(k).CodeChar = vCode(k).CodeChar & CStr (p) 46 Next 47 Next 48 Next 49 End Sub
识别验证码 1 Public Sub SpotCheckCode() ' 识别验证码 2 Dim BaseCode( 9 ) As String 3 BaseCode( 0 ) = " 011111111010000000011000000001100000000110000000010111111110 " 4 BaseCode( 1 ) = " 01000000010100000001111111111100000000010000000001 " 5 BaseCode( 2 ) = " 010000001110000001011000001001100001000110001000010111000001 " 6 BaseCode( 3 ) = " 010000001010000000011000100001100010000110001000010111011110 " 7 BaseCode( 4 ) = " 000001100000001010000011001000010000100111111111110000001001 " 8 BaseCode( 5 ) = " 111110001010001000011000100001100010000110001000011000011110 " 9 BaseCode( 6 ) = " 001111111001000100011000100001100010000110001000010000011110 " 10 BaseCode( 7 ) = " 110000000010000000111000001100100011000010110000001100000000 " 11 BaseCode( 8 ) = " 011101111010001000011000100001100010000110001000010111011110 " 12 BaseCode( 9 ) = " 011110000010000100011000010001100001000110001000100111111100 " 13 14 Dim i, k As Integer 15 Dim s As String 16 For k = 0 To 3 17 s = " $ " 18 For i = 0 To 9 19 If vCode(k).CodeChar = BaseCode(i) Then 20 s = CStr (i) : Exit For 21 End If 22 Next 23 TxtResult.Text = TxtResult.Text & s 24 Next 25 End Sub