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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Kuliah 02 : Citra Digital dan Matlab(beberapa slide diambil dari catatan kuliah Richard Alan Peters)
Yeni Herdiyeni
Departemen Ilmu Komputer – IPB
http://ilkom.fmipa.ipb.ac.id/yeni/ppcd/
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
3 September 2009 21999-2007 by Richard
Alan Peters II
Image Formation
projection through lens
image of object
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
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Image Sensing and Acquisition
• Other (MRI (Magnetic Resonance Imaging), Ultrasound)
Single Sensor
Line Scan
Array Sensor
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Jenis Sensor
• CCD (Charge Couple Device)
• CMOS (Complementary Metal Oxide Semi Conductor)
• Infra Red
• X-Ray
• Radar
• MRI (Magnetic Resonance Imaging)
• Radio Telescope
3 September 20091999-2007 by Richard Alan Peters
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra DigitalFundamentals
CCD = Charge Couple Device
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra DigitalFundamentals
CCD = Charge Couple Device
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
3 September 20091999-2007 by Richard Alan Peters
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
3 September 20091999-2007 by Richard Alan Peters
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Persepsi Visual Manusia
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
3 September 20091999-2007 by Richard Alan Peters
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Citra : Fungsi Kontinyu
• Citra kontinyu diperoleh dari sistem optik yang menerimasinyal analog, seperti mata manusia, kamera analog
• Citra diskrit/digital : dihasilkan dari proses digitalisasiterhadap citra kontinyu
3 September 20091999-2007 by Richard Alan Peters
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Sampling
3 September 20091999-2007 by Richard Alan Peters
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Y = sin(x) + 1/3 sin (3x)
Sampling adalah proses untuk menentukan warna pada piksel tertentu pada citra darisebuah gambar yang kontinu.
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Tahapan Sampling
3 September 20091999-2007 by Richard Alan Peters
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Sampling and Quantization
3 September 20091999-2007 by Richard Alan Peters
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sampledreal image quantized sampled &
quantized
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Sampling and Quantization
3 September 20091999-2007 by Richard Alan Peters
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sampledreal image quantized sampled &
quantized
pixel gridcolumn index
row
index
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Sampling
3 September 20091999-2007 by Richard Alan Peters
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),( crI S,CI
continuous image sampled image
Take the average within each square.
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Sampling
3 September 20091999-2007 by Richard Alan Peters
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),( crI S,CI
continuous image sampled image
Take the average within each square.
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Sampling
3 September 20091999-2007 by Richard Alan Peters
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),( crI S,CI
continuous image sampled image
Take the average within each square.
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Sampling
3 September 20091999-2007 by Richard Alan Peters
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),( crI S,CI
continuous image sampled image
Take the average within each square.
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Sampling dan Quantization
3 September 20091999-2007 by Richard Alan Peters
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Hasil Sampling dan Quantization
3 September 20091999-2007 by Richard Alan Peters
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
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Spatial Image Resolution:• Resolution
– The size of an area in a scene that is representedby one pixel in the image
• Different Resolutions are possible (256x256….16x16)
• Lower resolution leads to data reduction!
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Digital Image
3 September 20091999-2007 by Richard Alan Peters
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a grid of squares,
each of which
contains a single
color
each square is
called a pixel (for
picture element)
Color images have 3 values per
pixel; monochrome images have 1
value per pixel.
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Pixels
• A digital image, I, is a mapping from a 2D grid of uniformly spaced discrete points, {p = (r,c)}, into a set of positive integer values, {I( p)}, or a set of vector values, e.g., {[R GB]T(p)}.
• At each column location in each row of Ithere is a value.
• The pair ( p, I( p) ) is called a “pixel” (for picture element).
3 September 20091999-2007 by Richard Alan Peters
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Pixels
• p = (r,c) is the pixel location indexed by row, r, and column, c.
• I( p) = I(r,c) is the value of the pixel at location p.
• If I( p) is a single number then I is monochrome.
• If I( p) is a vector (ordered list of numbers) then I has multiple bands (e.g.,a color image).
3 September 20091999-2007 by Richard Alan Peters
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Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Pixels
3 September 20091999-2007 by Richard Alan Peters
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Pixel Location: p = (r , c)
Pixel Value: I(p) = I(r , c) Pixel : [ p, I(p)]
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Pixels
61
43
12
blue
green
red
)( pI
3 September 20091999-2007 by Richard Alan Peters
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277,272
col,row
,
##
crp
Pixel : [ p, I(p)]
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Tipe citra digital
3 September 20091999-2007 by Richard Alan Peters
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Citra Biner
Citra Keabuan
Citra BerwarnaCitra Indeks
Departemen Ilmu Komputer -IPBPengantar Pengolahan Citra Digital
Ukuran Citra
• Jika diasumsikan sebuah citra biner berukuran512 x 512, maka jumlah bit yang diperlukanuntuk menyimpan citra ini adalah
•
• 512 x 512 x 1 = 262.144 = 32.768 bytes
= 32, 768 Kb = 0.033 Mb (asumsi 1 Kb = 1000 byte).
3 September 20091999-2007 by Richard Alan Peters
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