Transformasi Fourier pada Image Processing

          Penerapan Transformasi Fourier pada Image Processing dapat dicontohkan pada cuplikan program VB berikut ini.

Langkah 1 : Buka program VB, kemudian buat property - property pada tabel berikut ini ke dalam form

Langkah 2 : Kemudian masukkan Program berikut ini kedalam code VB sesuai dengan Property di atas.

Dim n1, n2, m1, m2 As Single

Dim x(400, 400) As Single

Dim xr(400, 400), xi(400, 400) As Single

Private Sub Command1_Click()

n1 = 0

For i = 1 To Picture1.ScaleWidth Step 15

n1 = n1 + 1

n2 = 0

For j = 1 To Picture1.ScaleHeight Step 15

warna = Picture1.Point(i, j)

r = warna And RGB(255, 0, 0)

g = Int((warna And RGB(0, 255, 0)) / 256)

b = Int(Int((warna And RGB(0, 0, 255)) / 256) / 256)

n2 = n2 + 1

x(n1, n2) = Int((r + g + b) / 3)

Picture1.PSet (i, j), RGB(x(n1, n2), x(n1, n2), x(n1, n2))

Next j

Next i

Picture2.ScaleHeight = m1 + 1

Picture2.ScaleWidth = m2 + 1

Picture3.ScaleHeight = m1 + 1

Picture3.ScaleWidth = m2 + 1

For i = 1 To m1

For j = 1 To m2

fr = 0

fi = 0

For k1 = 1 To n1

For k2 = 1 To n2

fr = fr + x(k1, k2) * Cos(6.28 * (i * k1 / m1 + j * k2 / m2))

fi = fi - x(k1, k2) * Sin(6.28 * (i * k1 / m1 + j * k2 / m2))

Next k2

Next k1

w = 255 * Abs(fr) / (n1 * n2)

Picture2.Line (i - 0.5, j - 0.5)-(i + 0.5, j + 0.5), RGB(w, w, w), BF

w = 255 * Abs(fi) / (n1 * n2)

Picture3.Line (i - 0.5, j - 0.5)-(i + 0.5, j + 0.5), RGB(w, w, w), BF

xr(i, j) = fr

xi(i, j) = fi

Next j

Next i

End Sub

Private Sub Command2_Click()

Dim xa(100, 100), xg(100, 100) As Single

Picture4.ScaleHeight = m1 + 1

Picture4.ScaleWidth = m2 + 1

Picture5.ScaleHeight = m1 + 1

Picture5.ScaleWidth = m2 + 1

xam = 0

xgm = 0

For i = 1 To m1

For j = 1 To m2

xa(i, j) = (xr(i, j) ^ 2 + xi(i, j) ^ 2) ^ 0.5

xg(i, j) = xi(i, j) / xr(i, j)

If xa(i, j) > xam Then xam = xa(i, j)

If Abs(xg(i, j)) > xgm Then xgm = Abs(xg(i, j))

Next j

Next i

For i = 1 To m1

For j = 1 To m2

w = Int(256 * xa(i, j) / xam)

Picture4.Line (i - 0.5, j - 0.5)-(i + 0.5, j + 0.5), RGB(w, w, w), BF

w = Int(256 * Abs(xg(i, j)) / xgm)

Picture5.Line (i - 0.5, j - 0.5)-(i + 0.5, j + 0.5), RGB(w, w, w), BF

Next j

Next i

End Sub

Private Sub Command3_Click()

Unload Me

End Sub

Private Sub Form_Load()

m1 = 16: m2 = 16

End Sub

Langkah 3 : Run Program tersebut, maka hasilnya akan seperti pada gambar di bawah ini.

Sebelum

Sesudah

Langkah 4 : Done 

To be Continued....