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具体算法请参看《vb.net 教程 5-13 图像处理之像素处理 3》
灰度:均值法：
'灰度:均值法
'http://blog.csdn.net/uruseibest
Private Sub btnGray1_Click(sender As Object, e As EventArgs) Handles btnGray1.Click
Dim destImg As New Bitmap(sourceImg.Width, sourceImg.Height)
Dim sourceData As BitmapData = sourceImg.LockBits(New Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb)
Dim destData As BitmapData = destImg.LockBits(New Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb)
Dim pSource As IntPtr = sourceData.Scan0
Dim allBytes As Integer = sourceData.Stride * sourceData.Height
Dim rgbvalues() As Byte
ReDim rgbvalues(allBytes - 1)
Marshal.Copy(pSource, rgbvalues, 0, allBytes)
Dim pos As Integer = 0
Dim R, G, B As Integer
Dim avgValue As Integer
For j As Integer = 0 To sourceData.Height - 1
For i As Integer = 0 To sourceData.Width - 1
B = rgbvalues(pos)
G = rgbvalues(pos + 1)
R = rgbvalues(pos + 2)
avgValue = (B + G + R) / 3
rgbvalues(pos) = avgValue
rgbvalues(pos + 1) = avgValue
rgbvalues(pos + 2) = avgValue
pos = pos + 3
Next
pos = pos + sourceData.Stride - sourceData.Width * 3
Next
Dim pDest As IntPtr = destData.Scan0
Marshal.Copy(rgbvalues, 0, pDest, allBytes)
sourceImg.UnlockBits(sourceData)
destImg.UnlockBits(destData)
picDest.Image = destImg
End Sub
灰度:指数加权法：
'灰度:指数加权法
'http://blog.csdn.net/uruseibest
Private Sub btnGray2_Click(sender As Object, e As EventArgs) Handles btnGray2.Click
Dim destImg As New Bitmap(sourceImg.Width, sourceImg.Height)
Dim sourceData As BitmapData = sourceImg.LockBits(New Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb)
Dim destData As BitmapData = destImg.LockBits(New Rectangle(0, 0, sourceImg.Width, sourceImg.Height), ImageLockMode.WriteOnly, PixelFormat.Format24bppRgb)
Dim pSource As IntPtr = sourceData.Scan0
Dim allBytes As Integer = sourceData.Stride * sourceData.Height
Dim rgbvalues() As Byte
ReDim rgbvalues(allBytes - 1)
Marshal.Copy(pSource, rgbvalues, 0, allBytes)
Dim pos As Integer = 0
Dim R, G, B As Integer
Dim y As Integer
For j As Integer = 0 To sourceData.Height - 1
For i As Integer = 0 To sourceData.Width - 1
B = rgbvalues(pos)
G = rgbvalues(pos + 1)
R = rgbvalues(pos + 2)
y = R * 0.3 + G * 0.59 + B * 0.11
rgbvalues(pos) = y
rgbvalues(pos + 1) = y
rgbvalues(pos + 2) = y
pos = pos + 3
Next
pos = pos + sourceData.Stride - sourceData.Width * 3
Next
Dim pDest As IntPtr = destData.Scan0
Marshal.Copy(rgbvalues, 0, pDest, allBytes)
sourceImg.UnlockBits(sourceData)
destImg.UnlockBits(destData)
picDest.Image = destImg
End Sub
学习更多vb.net知识，请参看 vb.net教程 目录
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