3、逆反（底片）
算法：
原图像：颜色值color=（R，G，B）
新图像：
RNew=255-R
GNew=255-G
BNew=255-B
color=（RNew，GNew，BNew）
'逆反
Private Sub btnInversion_Click(sender As Object,e As EventArgs) Handles btnInversion.Click
Dim pSourceColor As Color
Dim pDestColor As Color
Dim destImg As New Bitmap(sourceImg.Width,sourceImg.Height)
Dim R,G,B As Integer
For i As Integer = 0 To sourceImg.Width - 1
For j As Integer = 0 To sourceImg.Height - 1
pSourceColor = sourceImg.GetPixel(i,j)
R = pSourceColor.R
G = pSourceColor.G
B = pSourceColor.B
R = 255 - R
G = 255 - G
B = 255 - B
pDestColor = Color.FromArgb(R,B)
destImg.SetPixel(i,j,pDestColor)
Next
Next
picDest.Image = destImg
End Sub
处理结果如下：
4、曝光
算法：先定义一个阈值，通常取得是128
原图像：颜色值color=（R，G，B）
新图像：
如果R<阈值，那么RNew=255-R
如果G<阈值，那么GNew=255-G
如果B<阈值，那么BNew=255-B
color=（RNew，GNew，BNew）
'曝光
Private Sub btnExposure_Click(sender As Object,e As EventArgs) Handles btnExposure.Click
Dim pSourceColor As Color
Dim pDestColor As Color
Dim destImg As New Bitmap(sourceImg.Width,j)
R = pSourceColor.R
G = pSourceColor.G
B = pSourceColor.B
If R < 128 Then R = 255 - R
If G < 128 Then G = 255 - G
If B < 128 Then B = 255 - B
pDestColor = Color.FromArgb(R,pDestColor)
Next
Next
picDest.Image = destImg
End Sub
处理结果如下：
由于.net平台下C#和vb.NET很相似，本文也可以为C#爱好者提供参考。
学习更多vb.net知识，请参看 vb.net 教程 目录