prinsip radiologi digital

1. Prinsip Dasar GambarPrinsip Dasar Gambar
Radiologi DigitalRadiologi Digital
SumarsonoSumarsono

6. Digital Pictures
♦Made up of discrete points associated with colors
• Image: 2D array of pixels
2D Image2D Image

7. Digital Pictures
♦Color representations
• Grayscale: 1 value representing grays from black (lowest
value) to white (highest value)
• 8-bit (0-255), 16-bit, etc.
• RGB: 3 values each representing colors from black
(lowest value) to pure red, green, or blue (highest value).
• 24-bit (0-255 in each color)
• XYZ, HSL/HSV, CMYK, etc.
GrayscaleGrayscale
LowLow HighHigh
RGBRGB
Low RLow R High RHigh R
Low GLow G High GHigh G
Low BLow B High BHigh B
RR GG
BB

8. Pengolahan Citra
Sistem Pengolahan Citra Digital

9. Sistem Pengolahan Citra Digital
♦Merupakan suatu kesatuan yang saling berhubungan
atau terintegrasi untuk membentuk suatu sistem
antara data, perangkat keras, perangkat lunak,
prosedure pengolahan, dan tenaga pelaksana dalam
ekplorasi citra digital

10. Konsep Dasar
♦ Pengolahan citra digital merupakan manipulasi dan interprestasi
digital dari citra dengan bantuan komputer. Konsep dasar
pengolahan citra dengan data masukan pokok (internal data) berupa
langkah berikut :
1. Pengumpulan data yang relevan, yaitu citra digital
2. Klasifikasi atau pengelompokan dengan cara pengkelasan
3. Penyusunan data sesuai kelas
4. Perhitungan dan manipulasi
5. Pengujian ketelitian dan perhitungan
6. Penyimpulan dan rekapitulasi hasil
7. Informasi

11. Software
1.Aplikasi Grafik
2.Pengolahan Citra Design
1. Rancangan Arsitektur
2. Rancangan Design
3. Animasi
3.Pengolahan Citra
1. Pengolah Citra
2. Pembuatan Efek
3. Contras
4. Brightness
5. Emboss

12. Hardware
♦ Perangkat Input
• Scanner
• Digital Camera
♦ Perangkat Output
• Printer
• Plotter
• Monitor
♦ Aspek penentuan kualitas citra dari perangkat keras :
• Resolusi
• Warna
• Kecepatan
• Kapasitas

13. Proses Pengolahan Data Citra Secara
Umum
CitraCitra ADCADC Citra DigitalCitra Digital
ProsesProses
KompresiKompresi
Media PenyimpanMedia Penyimpan
ProsesProses
DekompresiDekompresi
Citra DigitalCitra Digital Pengkodean Bit kePengkodean Bit ke
Tabel WarnaTabel Warna
LayarLayar

14. Perangkat Input Data
♦Perangkat input data yang digunakan diantaranya perangkat
penangkap atau capture citra yang bekerja membaca citra
dengan cara dijelajahi dan kemudian dilakukan proses
konfersi kedalam data digital.
♦Perangkat capture ini memiliki 3 (tiga) elemen dasar :
• Sensor intensitas cahaya
• Penjelajah untuk merekam seluruh bagian citra
• Analog Digital Converter (ADC)

15. Perangkat Output data
♦Diantara perangkat keras output diantaranya layar menggunakan
perangkat pengolah data yang dikenal sebagai Card VGA atau Display
Processor dengan cara kerja seperti terlihat dalam gambar berikut :
♦Display ProcessorCPUMemoryDisplay Processor
♦Layar
♦
I/O
♦
Display Processor akan mengubah digital ke analog, digunakan untuk
berinteraksi dengan CPU dan mengontrol operasi dari display device
CPUCPU
MemoryMemory
DisplayDisplay
ProcessorProcessor
LayarLayar

16. Mode Layar Monitor
♦Mode Teks :
• 25 x 80
• 25 x 40
♦Mode Grafiks (Resolusi)
• 320 x 200
• 640 x 200
• 640 x 400
• 800 x 600
• 640 x 480
• 1024 x 768
• 1180 x 1024
• 1600 x 1400
♦Dibedakan oleh adanya Pixel  Resolusi Layar Monitor
♦Resolusi adalah jumlah penembakan titik pada horizontal atau vertical tiap pixel oleh
elektron gun. Resolusi merupakan jumlah pixel percentimer vertical dan horizontal.

17. Monitor
♦ Tipe Resolusi
• High : Penampungan jumlah pixel pada layar maksimum
• Midle
• Low
♦ Tipe Monitor
• Monocrome
• CGA (Color Graphic Adapter)
• EGA (Enchanded Graphic Adapter)
• VGA (Video Graphic Array)
• SVGA (Super VGA)
• XGA (eXtra Graphic Array)
♦ Warna yang dihasilkan pada setiap monitor selain tergantung pada jenis monitor juga
tergantung dari interface yang berupa Card Monitor seperti VGA Card.
♦ Layar dari ukuran monitor terbatas dan tidak akan tampak jelas dilihat dari jarak jauh, untuk
keperluan tersebut digunakan Computer Display Projektor.

18. Sistem Monitor
♦Aspek Ratio (Y/X)
• Perbandingan antara Y dan X yang digunakan untuk mendapatkan panjang yang
sama antara garis vertical-horizontal yang dibutuhkan yaitu vertical 3 pixel dan
horizontal 4 pixel.
♦Random Scan Monitor
• Pengaksesan setiap titik secara langsung yang digunakan untuk menelusuri titik
pada tiap screen dengan cukup[ diwakili oleh 1 pixel
• Raster Scan Monitor
• Penggambaran suatu gambar yang sama dengan penelusuran setiap garis
• Refresh rate : 30 – 60 frames/sec
• Frame = banyak pixel pada layar
• Interlaced System : Teknik untuk mengatasi layar bergoyang, dengan cara
menampilkan tiap frame secara bergantian.

19. Jumlah Warna
♦Setiap Pixel dapat menampilakan 1 warna
♦Total warna yang dapat ditampilkan dapat ditentukan, sebagai contoh
Monitor resolusi 800 x 600 warna yang ditampilkan 16,7 Juta warna, memori yang
dibutuhkan  16,7 Juta = 24 Bit
Jumlah Pixel = 800 x 600 = 480.000
1 Pixel  24 Bit = 3 Byte
480.000 x 3 / 1024 = 1440 Kb = 1,44 Mb
2 4 16 256 64K 16,7 M …… Warna
High Color True Color
1 2 4 8 16 24 …. Bit

20. Image Media Types
♦Images can be generally divided into two formats:
• Bitmapped or Raster images
• Draw-type or Vector graphics or Metafile images
♦Bitmapped images are stored as an array of pixels. It
represents the image as an array of dots, called pixels
♦Vector graphics are stored as geometric shape to represent
the image

21. Bitmaps Image
♦A pixel is the smallest element of resolution on a computer screen
(Screen Resolution)
♦A pixel is the basic unit of a digital images. Digital image is a picture
that may be stored in, displayed on, processed by a computer.
♦As mentioned, bitmap is composed of a matrix elements called pixels
♦Each pixel can be in a specific colour and each pixel consists of two or
more colors.

22. Bitmaps Image
♦The range of these colours is known as the colour depth.
♦The color depth determined “How much data in bits used to
determined the number of colors”.
♦Colour depth is measured in bits per pixel
• Remember: a bit (binary digit) is either 1 or 0 and that there are
eight bits in a byte

23. Colour depth
♦1 bit per pixel = 2 colours (monochrome)
♦2 bits per pixel = 4 colours
♦4 bits per pixel = 16 colours
♦8 bits per pixel = 256 colours
• Generally good enough for colour images
♦16 bits per pixel = 65536 colours
• Better quality for photograph-like images, also known as high colour

24. Bitmaps Image
♦The more colours that are allowed per pixel, the greater the
size of the image
♦The number of pixels is related to the size of file that
required to store an image.
♦Remember, two factors effect the size file bitmap are:
• Resolution
• Color Depth

25. Bitmaps images
Original imageOriginal image
ShownShown
magnifiedmagnified

26. 8
bytesinsize
depthcolourheightwidth ××
=
Calculating the size
of a raster image
♦Where:
• Width of the images measured in pixels
• Height of the images measured in pixels
• Colour depth is the number of bits used for color measured in bits per pixel
♦Remember:
• 1024 bytes = 1 kilobyte (KB)
• 1024 kilobytes = 1 megabyte (MB)

27. Example
♦A 640 x 480 pixel image in 24-bit colour would require how
much disk space?
900KB
bytes921600
8
7372800
8
24480640
bytesinsize
=
=
=
××
=

28. Popular bitmap formats
♦ Microsoft bitmap (.bmp)
• Used in microsoft windows
♦ TIFF - Tagged Image File Format (.tif)
• Used for faxing images (amongst other things)
♦ JPEG - Joint Photographic Expert Group (.jpg)
• Useful for storing photographic images
♦ GIF - Graphics Interchange Format (.gif)
• Used a lot on web sites
♦ PNG - Portable Network Graphics (.png)
• A new format for web graphics
♦ PCD – Kodak photo CD
• A new format for store image in a compressed form on a CD

29. Advantages and Disadvantages
of using bitmap images
♦Advantages
• Convey detail of information quickly
• Real life
♦Disadvantages
• Depend on a Resolution
• Effect to the image quality
• Size file is big

30. Software to create bitmap images
♦Popular PC packages include:
• Microsoft Paint
• Included with microsoft windows
• Microsoft PhotoDraw 2000
• http://www.microsoft.com/office/photodraw/
• Adobe Photoshop
• http://www.adobe.com/products/photoshop/main.html
• Paint Shop Pro
• http://www.jasc.com/psp6.html
• Macromedia Fireworks
• http://www.macromedia.com/software/fireworks/productinfo/

31. Vector images
♦Vector images are stored as the set of graphic primitives
required to represent the image
♦A graphic primitive is a simple graphic based on drawing
elements or objects such as shape
• e.g. square, line, ellipse, arc, etc.
♦The image consists of a set of commands (mathematical
equations) that are drawn the object when needed.

32. Vector images
♦Storing and representing images by mathematical equations is called
vector graphics or Object Oriented graphics.
♦Each primitive object has various attributes that go to make up the
entire image
• e.g. x-y location, fill colour, line colour, line style, etc.
♦Example:
• RECTANGLE : rectangle top, left, width, height, color is ( 0, 0, 200, 200, red)
• CIRCLE : circle top, left, radius, color
• LINE : Line x1, y1, x2, y2, color

33. Vector images
♦Vector image or vector graphics can be resized without
losing the integrity of the original image.
♦Scaling a vector is a mathematical operation - only the
attributes change, the image is unaffected

34. Primitive geometric drawing objects
♦Shapes
• Circle
• Ellipse
• Rectangle
• Square
• Pie segment
• Triangle
• Pentagon,
hexagon,
heptagon,
octagon, etc
♦Basic
• Line
• Polyline
• Arc
• Bezier curve
♦Text
• Font, weight T e x tT e x t

35. Scaling vector graphics
Original imageOriginal image
V e c t o r
g r a p h i c s
ShownShown
magnifiedmagnified
V e c t o r
g r a p h i c s

36. Advantages and Disadvantages
of using vector image
♦Advantages
• Relatively small amount of data required to represent the
image.
• Therefore, it does not required a lot of memory to store
• Easier to manipulate
♦Disadvantages
• Limited level of detail than can be presented in an image

37. Software to create images
♦Graphics programs are tools that allow an artist to create and edit
designs used in multimedia applications.
♦Generally, graphics programs can be categorized as:
• Drawing programs
• Creating draw type graphics
• Provide freehand. Example geometric shape
• Example : Adobe Illustrator, Corel Draw, Macromedia Freehand
• Paint programs
• Those creating bitmaps
• Useful in creating original art
• Example: Paint Shop Pro
• Image editing programs
• Making changes to existing images, such as manipulating the brightness or contrast,
applying textures, patterns
• Examples : Adobe Photoshop, Corel PhotoPaint

38. Vector formats
♦ Windows metafile (.wmf)
• Used by Microsoft Windows
♦ SVG - Scalable Vector Graphics (.svg)
• A new format devised for the web
♦ CGM - Computer Graphics Metafile (.cgm)
• Older format commonly used for clip art
♦ Adobe PostScript (.ps)
• A page description language used to control printers
♦ Adobe Portable Document Format (.pdf)
• A page description language common on the web
♦ Drawing Exchange Format (.dfx)
• Store 3D image created by design program AutoCAD

39. 3-Dimensional Graphic models
♦A 3D model is a variation on the vector
format
♦The location of a 3-dimensional object
is specified using x, y and z co-
ordinates
♦Further primitives can be found in 3D
models
• Cube, sphere, pyramid, etc.
• Camera, spotlight, texture, shading etc.
3D model3D model
XX
YY
ZZ

40. 3-Dimensional Graphic models
♦3D graphics offer the photorealistics effects that have you
seen in TV, Computer Games
♦Examples, Motion Picture films such as:
• Jurassic Park, Terminator 2, Lost World and Toy Story
♦Examples 3D programs:
• Carigali Truespace
• 3D Studio Max
• Infini-D

41. 3-Dimensional Graphic models

42. Hardware used to acquire images
♦Scanners and digital imaging products
♦Many forms of scanner
• Drum
• Flat-bed
• Negative / slide
• Hand-held
♦Important to check the optical resolution of
the scanner
• measured in dots per inch (DPI)

43. Hardware used to acquire images
♦Digital camera
• Uses digital memory instead of film
• Images are transferred to computer via a
cable
• Can be very high resolution
♦Stills from a camcorder or PC “web-
cam” type camera
• Home products tend to be low resolution

44. Hardware used to create / edit images
♦Graphics tablet and pen
• Preferred by digital artists
• Pressure sensitivity
♦Digitiser tablet
• Preferred by technical artists
• Mouse has accurate crosshair to
help digitise drawings
Tablet and penTablet and pen
DigitiserDigitiser

45. Converting image formatsTextTextTextText
BitmappedimageBitmappedimageBitmappedimageBitmappedimage
VectorimageVectorimageVectorimageVectorimage
Bitmapped fontBitmapped font
TrueType / PostScript Type fontTrueType / PostScript Type font
Optical CharacterOptical Character
Recognition (OCR)Recognition (OCR)
Contour traceContour trace
Render as bitmapRender as bitmap

46. Digital Pictures
♦Made up of discrete points associated with colors
• Volume: 3D array of voxels
3D Volume3D Volume
VoxelVoxel

47. 1
2
3
1 2 3 4
5
Matrix 4x 5
Ukuran Matriks baris pixel x kolom = 20 pixelUkuran Matriks baris pixel x kolom = 20 pixel

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AA
BB
FOV: 10 cmFOV: 10 cm
Pixel Size: 1 cmPixel Size: 1 cm
FOV:FOV:
Pixel Size:Pixel Size:
10 cm10 cm
2 cm2 cm

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AA BB
FOV: 10 cmFOV: 10 cm
Pixel Size: 1 cmPixel Size: 1 cm
FOV:FOV:
Pixel Size:Pixel Size:
5 cm5 cm
1 cm1 cm

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FOV: 10 cmFOV: 10 cm
Pixel Size: 1 cmPixel Size: 1 cm
FOV:FOV:
Pixel Size:Pixel Size:
20 cm20 cm
2 cm2 cm