lecture notes: digital images and matlabyeni/files/ppcd/kuliah 02 - pengolahan citra... · 1...

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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/


3 September 2009 21999-2007 by Richard

Alan Peters II

Image Formation

projection through lens

image of object


3

Image Sensing and Acquisition

• Other (MRI (Magnetic Resonance Imaging), Ultrasound)

Single Sensor

Line Scan

Array Sensor


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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Persepsi Visual Manusia





3





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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


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Sampling


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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.


Tahapan Sampling


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4


Sampling and Quantization


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sampledreal image quantized sampled &

quantized


Sampling and Quantization


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sampledreal image quantized sampled &

quantized

pixel gridcolumn index

row

index


Sampling


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),( crI S,CI

continuous image sampled image

Take the average within each square.


Sampling


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),( crI S,CI




Sampling


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),( crI S,CI




Sampling


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),( crI S,CI



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Sampling dan Quantization


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Hasil Sampling dan Quantization


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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!


Digital Image


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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.


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).


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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).


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6


Pixels


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Pixel Location: p = (r , c)

Pixel Value: I(p) = I(r , c) Pixel : [ p, I(p)]


Pixels

61

43

12

blue

green

red

)( pI


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277,272

col,row

,

##

crp

Pixel : [ p, I(p)]


Tipe citra digital


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Citra Biner

Citra Keabuan

Citra BerwarnaCitra Indeks


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).


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lecture notes: digital images and matlabyeni/files/ppcd/kuliah 02 - pengolahan citra... · 1...

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