用vb.net写的验证码识别代码

一个很简单用vb.net写的验证码识别代码，代码质量不是太高，而且去噪部分算法很不好，但识别现在网站上的图形验证码已经够用了。比起前段时间给一群 人渣做的自动投票系统中用的一个带有相当强大的图形处理类的ocr来识别和去噪相比就差太远了，放代码只是提醒下要注意登陆入口的管理和管理员的密码安全 性，只要我能有一定的几率正确识别图形验证码，就能通过向http包头中添加新的头信息，就能对管理员帐号进行暴力破解:

Imports System
Imports System.Text
Imports System.Data
Imports System.Data.OleDb
Imports System.Drawing
Imports System.Drawing.Graphics

Public Class CrackImage

Private ConnStr As String = "Provider=Microsoft.Jet.OLEDB.4.0;User ID=Admin;Data Source=Learn.mdb"
Private resultNumber As String
Private rsultStudy As Boolean = False

'识别
Public Sub New(ByVal SrcImage As Bitmap)
GetImageNumber = GetIamgeResultNumber(GetNewIamge(SrcImage))
End Sub

'学习
Public Sub New(ByVal SrcImagePath As String, ByVal StudyNumber As String)
rsultStudy = StudyCode(SrcImagePath, StudyNumber)
End Sub

Public Property GetImageNumber() As String
Get
Return resultNumber
End Get
Set(ByVal Value As String)
resultNumber = Value
End Set
End Property

Public Property GetStudyImageResult() As Boolean
Get
Return rsultStudy
End Get
Set(ByVal Value As Boolean)
rsultStudy = Value
End Set
End Property

'处理新图片
Private Function GetNewIamge(ByVal srcBitBmpImage As Bitmap) As Bitmap
'建立临时表
Dim myDataTable As New DataTable
Dim myCol2 As New DataColumn
myCol2.DataType = System.Type.GetType("System.Int32")
myCol2.ColumnName = "RgbValue"
myDataTable.Columns.Add(myCol2)

Dim myCol3 As New DataColumn
myCol3.DataType = System.Type.GetType("System.Int32")
myCol3.ColumnName = "RgbCount"
myDataTable.Columns.Add(myCol3)

'载入图片
Dim img As Bitmap = srcBitBmpImage
Dim x, y As Integer

'去除杂点
'遍历所有点，存储每点的颜色代码，并对各种颜色进行统计 （这些代码可以不要，直接将图转化成黑白只剩下噪点和感染线条）
For x = 0 To img.Width - 1
For y = 0 To img.Height - 1
Dim Found As Boolean = False
If myDataTable.Rows.Count > 0 Then
For k As Integer = 0 To myDataTable.Rows.Count - 1
If myDataTable.Rows(k).Item("RgbValue") = img.GetPixel(x, y).ToArgb Then
myDataTable.Rows(k).Item("RgbCount") += 1
Found = True
Exit For
End If
Next
End If

If Found = False Then
Dim myRow As DataRow
myRow = myDataTable.NewRow()
myRow.Item("RgbValue") = img.GetPixel(x, y).ToArgb
myRow.Item("RgbCount") = 1
myDataTable.Rows.Add(myRow)
End If
Next
Next

'获取背景色码
'象素点出现最多的就视为背景色
Dim intMaxRgbValue As Integer = 0
If myDataTable.Rows.Count > 0 Then
myDataTable.DefaultView.Sort = "RgbCount DESC"
intMaxRgbValue = myDataTable.DefaultView.Item(0).Item("RgbValue")
End If

'勾画数字轮廓
For x = 0 To img.Width - 1
For y = 0 To img.Height - 1
Dim x1, y1 As Integer 'x1和y1记录的是相对当前象素的上一个象素的坐标
If x = 0 Then
x1 = x
Else
x1 = x - 1
End If

If y = 0 Then
y1 = y
Else
y1 = y - 1
End If

Dim x2, y2 As Integer 'x2和y2记录的是相对当前象素下一个象素的坐标
If x = img.Width - 1 Then
x2 = img.Width - 1
Else
x2 = x + 1
End If

If y = img.Height - 1 Then
y2 = img.Height - 1
Else
y2 = y + 1
End If

'都是普通的去噪手法，去噪成黑白色，这里是去噪成黑黄 色
If img.GetPixel(x2, y).ToArgb = intMaxRgbValue Or img.GetPixel(x1, y).ToArgb = intMaxRgbValue Then
img.SetPixel(x, y, Color.Black)
ElseIf img.GetPixel(x, y).ToArgb <> intMaxRgbValue Then
img.SetPixel(x, y, Color.Yellow)
Else
img.SetPixel(x, y, Color.Black)
End If
Next
Next

Return img
End Function

'获取处理后的数字
Private Function GetIamgeResultNumber(ByVal srcNewImg As Bitmap) As String
Dim RawData As New StringBuilder
'设置分割大小
Dim imgNewWidth As Integer = 16
Dim imgNewHeight As Integer = 13

Dim imgNew As New Bitmap(srcNewImg)
Dim x, y As Integer
Dim result As String = ""

Dim ImageSplitWidth As Integer = imgNew.Width - imgNewWidth

For m As Integer = 0 To ImageSplitWidth Step imgNewWidth
Dim Rc As New Rectangle(m, 0, imgNewWidth, imgNewHeight)
Dim B As Bitmap
B = imgNew.Clone(Rc, imgNew.PixelFormat)
'对比分割的颜色，黑色取1，其他取0，就此生成特征码
For x = 0 To imgNewWidth - 1
For y = 0 To imgNewHeight - 1
If B.GetPixel(x, y).ToArgb <> Color.Black.ToArgb Then
RawData.Append("1")
Else
RawData.Append("0")
End If
Next
Next

result += GetIamgeRawToNumber(RawData.ToString)
RawData.Replace("0", "").Replace("1", "")
Next

Return result
End Function

'学习新图片
Private Function StudyCode(ByVal srcImage As String, ByVal objNumber As String) As Boolean
If objNumber = "" Or objNumber.Length < 4 Then Exit Function
Dim RawData As New StringBuilder
Dim imgNewWidth As Integer = 16
Dim imgNewHeight As Integer = 13
Dim p As Integer = 0
Dim x, y As Integer

Dim srcBitbmp As New Bitmap(srcImage)
Dim imgNew As Bitmap = GetNewIamge(srcBitbmp)

'分割图片并保存学习代码
Dim ImageSplitWidth As Integer = imgNew.Width - imgNewWidth
For m As Integer = 0 To ImageSplitWidth Step imgNewWidth
Dim CurNumber As String
CurNumber = objNumber.Substring(p, 1)
If CurNumber <> "." Then
Dim Rc As New Rectangle(m, 0, imgNewWidth, imgNewHeight)
Dim B As Bitmap
B = imgNew.Clone(Rc, imgNew.PixelFormat)

For x = 0 To imgNewWidth - 1
For y = 0 To imgNewHeight - 1
If B.GetPixel(x, y).ToArgb <> Color.Black.ToArgb Then
RawData.Append("1")
Else
RawData.Append("0")
End If
Next
Next
SaveImageRaw(objNumber.Substring(p, 1), RawData.ToString)
RawData.Replace("0", "").Replace("1", "")
End If
p += 1
Next

Return True
End Function

'获取图片Raw数据
Private Function GetIamgeRawToNumber(ByVal strRaw As String) As String
Dim conn As New OleDbConnection(ConnStr)
Dim comm As New OleDbCommand
Dim reader As OleDbDataReader

Dim myDataTable As New DataTable
Dim myCol1 As New DataColumn
myCol1.DataType = System.Type.GetType("System.Int32")
myCol1.ColumnName = "MatchNumber"
myDataTable.Columns.Add(myCol1)

Dim myCol2 As New DataColumn
myCol2.DataType = System.Type.GetType("System.Int32")
myCol2.ColumnName = "MatchCount"
myDataTable.Columns.Add(myCol2)

comm.CommandText = "select LearnCharacter,Eigenvalue from tbLearn"
conn.Open()
comm.Connection = conn
reader = comm.ExecuteReader

If reader.HasRows Then
While reader.Read
Dim myRow As DataRow
myRow = myDataTable.NewRow()
myRow.Item("MatchNumber") = reader.Item(0)
myRow.Item("MatchCount") = CompareRaw(reader.Item(1), strRaw)
myDataTable.Rows.Add(myRow)
End While
End If
conn.Close()

Dim reuslt As String = ""
If myDataTable.Rows.Count > 0 Then
myDataTable.DefaultView.Sort = "MatchCount DESC"
reuslt = myDataTable.DefaultView.Item(0).Item("MatchNumber")
End If

Return reuslt

End Function

'比较图片Raw数据
Private Function CompareRaw(ByVal strDataBaseRaw As String, ByVal strObjRaw As String) As Integer
Dim intRawLen As Integer = strDataBaseRaw.Length
Dim MatchCount As Integer = 0
For i As Integer = 0 To intRawLen - 1
If strDataBaseRaw.Substring(i, 1) = strObjRaw.Substring(i, 1) Then
MatchCount += 1
End If
Next
Return MatchCount
End Function

'保存图片Raw数据
Private Sub SaveImageRaw(ByVal strNumber As String, ByVal strRaw As String)
Dim conn As New OleDbConnection(ConnStr)
Dim comm As New OleDbCommand
comm.CommandText = "insert into tbLearn(LearnCharacter,Eigenvalue) values ('" + strNumber + "','" + strRaw + "')"
conn.Open()
comm.Connection = conn
comm.ExecuteNonQuery()
conn.Close()
End Sub

End Class