Imports System.Drawing.Imaging
Public Class Form1
Private Bmp As Bitmap = New Bitmap(“C:\aaa.jpg”)
Private eBmp As Bitmap
Private Sub Picture_Box(ByVal sender As Object, ByVal e As PaintEventArgs) Handles PictureBox1.Paint
If eBmp Is Nothing Then Exit Sub
e.Graphics.DrawImage(eBmp, 0, 0)
End Sub
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
EdgeDetection()
PictureBox1.Invalidate()
End Sub
Private Sub EdgeDetection()
GrayScale(Bmp)
eBmp = New Bitmap(bmp.Width, bmp.Height, PixelFormat.Format24bppRgb)
Dim Col(8) As Color
Dim newR As Integer, newG As Integer, newB As Integer
Dim skew As Integer = -0
Dim around As Integer = -5
Dim center As Integer = 24
Dim s() As Single = {skew, around, skew, _
around, center, around, _
skew, around, skew}
Dim wa As Integer
For i As Integer = 0 To UBound(s)
wa += s(i)
Next
For y As Integer = 1 To bmp.Height – 2
For x As Integer = 1 To bmp.Width – 2
Col(0) = bmp.GetPixel(x – 1, y – 1)
Col(1) = bmp.GetPixel(x, y – 1)
Col(2) = bmp.GetPixel(x + 1, y – 1)
Col(3) = bmp.GetPixel(x – 1, y)
Col(4) = bmp.GetPixel(x, y)
Col(5) = bmp.GetPixel(x + 1, y)
Col(6) = bmp.GetPixel(x – 1, y + 1)
Col(7) = bmp.GetPixel(x, y + 1)
Col(8) = bmp.GetPixel(x + 1, y + 1)
For k As Integer = 0 To 8
newR += Col(k).R * s(k)
newG += Col(k).G * s(k)
newB += Col(k).B * s(k)
Next
newR = Math.Min(Math.Max(newR, 0), 255)
newG = Math.Min(Math.Max(newG, 0), 255)
newB = Math.Min(Math.Max(newB, 0), 255)
eBmp.SetPixel(x, y, Color.FromArgb(newR, newG, newB))
Next
Next
End Sub
Public Sub GrayScale(ByRef srcBmp As Bitmap)
Dim col As Color
Dim int As Integer
For y As Integer = 0 To srcBmp.Height – 1
For x As Integer = 0 To srcBmp.Width – 1
col = srcBmp.GetPixel(x, y)
int = Math.Min(col.R * 0.299 + col.G * 0.587 + col.B * 0.114, 255)
srcBmp.SetPixel(x, y, Color.FromArgb(int, int, int))
Next
Next
End Sub
End Class
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