用来检测物体的灰度值的代码，为什么用久了会卡
[code][/Private Sub Timer1_Timer()
 Dim h As Long, dc As Long
 Dim Xa As Long, Xb As Long, Xc As Long, Xd As Long, Xe As Long

 Dim Ra As Byte, Ga As Byte, Ba As Byte, Rb As Byte, Gb As Byte, Bb As Byte, Rc As Byte, Gc As Byte, Bc As Byte, Rd As Byte, Gd As Byte, Bd As Byte, Re As Byte, Ge As Byte, Be As Byte

 dc = GetDC(0)
 Xa = GetPixel(dc, heng, zong)
 Ra = (Xa Mod 256) \ 16
 Ga = (Xa Mod 65536) \ 256
 Ba = (Xa Mod 16777216) \ 65536
 ReleaseDC dc, 0
 Na = Ra / 3 + Ga / 3 + Ba / 3
 Za = Int(Abs(Na - Ca))

 Xb = GetPixel(dc, heng - 16, zong)
 Rb = (Xb Mod 256) \ 16
 Gb = (Xb Mod 65536) \ 256
 Bb = (Xb Mod 16777216) \ 65536
 ReleaseDC dc, 0
 Nb = Ra / 3 + Ga / 3 + Ba / 3
 Zb = Int(Abs(Nb - Cb))

 Xc = GetPixel(dc, heng + 16, zong)
 Rc = (Xc Mod 256) \ 16
 Gc = (Xc Mod 65536) \ 256
 Bc = (Xc Mod 16777216) \ 65536
 ReleaseDC dc, 0
 Nc = Rc / 3 + Gc / 3 + Bc / 3
 Zc = Int(Abs(Nc - Cc))

 Xd = GetPixel(dc, heng + 8, zong)
 Rd = (Xd Mod 256) \ 16
 Gd = (Xd Mod 65536) \ 256
 Bd = (Xd Mod 16777216) \ 65536
 ReleaseDC dc, 0
 Nd = Rd / 3 + Gd / 3 + Bd / 3
 Zd = Int(Abs(Nd - Cd))

 Xe = GetPixel(dc, heng - 8, zong)
 Re = (Xc Mod 256) \ 16
 Ge = (Xc Mod 65536) \ 256
 Be = (Xc Mod 16777216) \ 65536
 ReleaseDC dc, 0
 Ne = Re / 3 + Ge / 3 + Be / 3
 Ze = Int(Abs(Ne - Ce))



 Text5.Text = Za & "*" & Zb & "*" & Zc & "*" & Zd & "*" & Ze

 If Za > 25 Or Zb > 25 Or Zc > 25 Or Zc > 25 Or Zc > 25 Then
 Sleep (50)
 Else
 Exit Sub
 End If
 If Za > 25 Or Zb > 25 Or Zc > 25 Or Zc > 25 Or Zc > 25 Then
 M = M + 1
 Text1.Text = M & "辆"
T1 = GetTickCount()
 DoEvents
 Sleep (50)
 Else
 Exit Sub
 End If
 Timer2.Enabled = True
 DoEvents
 Timer1.Enabled = False
 End Subcode]