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G0Q55A – Multimedia: modelleren en programmeren 2007/2008 Martin Wolpers & Erik Duval 09 November 2007 1

G0Q55A – Multimedia: modelleren en programmeren 2007/2008 Martin Wolpers & Erik Duval 09 November 2007 1

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G0Q55A – Multimedia: modelleren en programmeren 2007/2008

Martin Wolpers & Erik Duval

09 November 2007

1

Group presentation groups Some secrets of images Java & Java Media Framework Java Assignment

G0Q55A – Multimedia: modelleren en programmeren 2007/2008 2

Group 5 Jan Sebrechts Sébastien Devynck Pieter Gevers Kim Gressens Iwein Vranckx

Group 6 Jelle Wardenier Laurens Serneels Stijn Adriaensens Tim Boven

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Digital images vs. Analog images

Here Digital representations of images

No video! No recording! No capturing!

Presentation based on Fundamentals of Multimedia, Li&Drew, Prentice Hall 2003

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Color models (RGB vs. CYM) Gray Images

1-bit Gray scale

Color images (GIF) Color images compression (JPG)

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RGB: Red – Green – Blue For monitors: colors add

CMY: Cyan – Magenta – Yellow For printing: colors subtract

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G0Q55A – Multimedia: modelleren en programmeren 2007/2008 8

C 1 RM = 1 - GY 1 B

R 1 CG = 1 - MB 1 Y

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Color ~ (Voltage of color electron gun)gamma

=> not enough light with low voltages

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1-bit: white or black 640x480~37,5 kByte

Pixel??

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Graphic from www.wikipedia.org

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1 pixel = 1 gray value 1 gray value = 1 byte Bitmap = cube with dimension

image size x 8 bit Size 640x480x1Byte

= 300kByte E.g. bmp

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Transform 1 pixel to larger pattern Used for 1-bit printers Example

2x2 dither matrix: transform [0..255] -> [0..4] 0:0 1: [1..63], 2:[64..127], 3:[128..191], 4:

[192..255] Better ideas?

Size: 4x640x480x1Byte

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24-bit color images 3 channels, 1 Byte per channel 256x256x256 colors (~16M) (more later) Size: 640x480x24bit ~ 900kByte

32-bit color images 24-bit images + special effects channel (1

Byte) 8-bit color images

No direct color information Color look-up index

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900kByte300kByte

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1byte index into color palette (256 colors) Size: 1bytex640x480 ~ 300kByte

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Bitmaps and Container TIFF WMF 8-bit GIF

PNG JPEG

EXIF

Vector formats PS and PDF SVG

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TIFF: stands for Tagged Image File Format.

Attachment of additional information (referred to as “tags”) Flexibility

Most important tagformat signifier: type of compression etc. TIFF can store many different types of image

1-bit, grayscale, 8-bit color, 24-bit RGB, etc. TIFF is lossless format but JPEG compression

possible

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Microsoft Windows: WMF native vector file format: Consist of a collection of GDI (Graphics Device

Interface) function calls, also native to the Window environment.

“played” a file (typically using the Windows PlayMetaFile() function) == render graphics

Device-independent and unlimited in size.

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Graphics Interchange Format GIF87a (original) GIF89a (extension for simple animations)

8-bit color images Interlacing

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GIF Signatur

Screen Descriptor

Global Color Map

Image Descriptor

Local Color Map

Raster Area

GIF Terminator

Repeat n times

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Length: 2^(Pixel+1)

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PNG format: standing for Portable Network Graphics

→ meant to supersede the GIF standard, and extends it in important ways.

Special features of PNG files include: Support for up to 48 bits of color information — a

large increase. contain gamma-correction and alpha-channel

information Progressive display (2-dimensional fashion in

seven passes through each 8 × 8 block)

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JPEG Image compression standard (Joint

Photographic Experts Group) 1992 JPEG is a lossy image compression

method transform coding method using the

DCT (Discrete Cosine Transform). An image = F(i, j) in the spatial domain.

2D DCT yields a frequency response which is a function F(u, v) in the spatial frequency domain

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Observation 1 Intensity does not change widely in small

areas Observation 2

High spatial frequency less noticed by humans Observation 3

Visual acuity (accuracy in distinguishing closely spaced lines) is much greater for gray (“black and white”) than for color.

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Original 20% 5%

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EXIF (Exchange Image File) used for digital cameras: Compressed EXIF files use the baseline JPEG

format. Tags (many more than in TIFF) facilitate

higher quality printing, more information about the camera picture-taking conditions (flash, exposure, light

source, white balance, type of scene, etc.) Specification of file format for audio that

accompanies digital images.

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Images made up of simple mathematically describable geometrical forms E.g. lines, polygons, circles, bezier curves, etc. Combined and transformed to form complex

objects

File formats PS and PDF SVG: xml based, WWW consortium WMF: windows

Text, too: True Type fonts

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Layout and Content are true-copy enabled!

Postscript – language for typesetting Vector-based picture language

Postscript includes text as well as vector/structured graphics.

GL bit-mapped images included in output Encapsulated Postscript (eps) files add additional

information for inclusion no compression (stored as ASCII)

Portable Document format (PDF) LZW compression Without images (compression ratio, 2:1 or 3:1)

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Graphic from www.wikipedia.org

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Filtershttp://www.ph.tn.tudelft.nl/Courses/FIP/noframes/fip-Morpholo.html

Image processing at TU Delft http://www.ph.tn.tudelft.nl/Courses/FIP/noframes/fip.html

Java Tutorial http://java.sun.com/docs/books/

tutorial/

Java Media Framework http://java.sun.com/products/java-

media/jmf/

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Implementation of your CO2 calculator in JavaFollow strictly (!!) Your Storyboard Your Flow Chart /State Diagram Your Layout Your Timeline

Running Applet (!) including source code documentation

Deadline: 21.11.2007

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Applet works; name restrictions Programming Syle: readalbe, structured,

layout, naming, ... Document differences to flash, smil, etc.

wnd why! Say who did what for how long Used tools

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