Your SlideShare is downloading. ×
computer graphics
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×

Saving this for later?

Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime - even offline.

Text the download link to your phone

Standard text messaging rates apply

computer graphics

2,661
views

Published on

ita computer graphics presentation

ita computer graphics presentation

Published in: Education

0 Comments
3 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
2,661
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
200
Comments
0
Likes
3
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide
  • Many hidden surface removal algorithms have been developed
  • Transcript

    • 1. Introduction to Computer Graphics Pradondet Nilagupta Dept. of Computer Engineering Kasetsart University204481 Foundation of Computer Graphics March 7, 2013 1
    • 2. Lecture Outline  Course Information: Format, Resources  Overview  Topics covered  What is computer graphics?  Applications204481 Foundation ofComputer Graphics March 7, 2013 2
    • 3. Course Info and Administrative  Instructor: Pradondet Nilagupta  E-mail: pom@ku.ac.th  Phone: 9428555 ext. 1415 (office)  Office hours: after class; 1-2pm Monday or by appointment  Web Page  Course Homepage: http://www.cpe.ku.ac.th/~pom/courses/204481/ 204481.html  Course Syllabus: http://www.cpe.ku.ac.th/~pom/courses/204481/syllabus.html204481 Foundation ofComputer Graphics March 7, 2013 3
    • 4. Course Overview (1/2)  Graphics Systems and Techniques  2-D, 3-D models: surfaces, visible surface identification, illumination  Photorealistic rendering : shading models, ray tracing, radiosity  Operations  Surface modeling, mapping  Pipelines for display, transformation, illumination204481 Foundation ofComputer Graphics March 7, 2013 4
    • 5. Course Overview (2/2)  Mathematical Review  Review of mathematical foundations of CG: analytic geometry, linear algebra  Line and polygon rendering  Matrix transformations204481 Foundation ofComputer Graphics March 7, 2013 5
    • 6. Relevant Disciplines Rendering Hardware CAD Immersive Training VR Systems CAE / CASE  Analytic Geometry Portable/Embedded CG CAM Tutoring Interfaces  Art and Graphic Design  Cognitive Science Color/Optical Models CG/Vision Duality  Computer Engineering Interface Design  Engineering Design Layout CG Design  Education Visualization  Film Parametric Equations  Human Factors Conics Computer Polygon Rendering  Linear Algebra Graphics  Numerical Analysis (CG) Surface Modeling Physically-Based Modeling Stat/Info Visualization Transformations Change of Coordinate Systems User Modeling Animation204481 Foundation of Ergonomic Interfaces, I/O Large-Scale CGComputer Graphics March 7, 2013 6
    • 7. What is Computer Graphics?204481 Foundation of Computer Graphics March 7, 2013 7
    • 8. This is not Computer Graphics 1% 8 9% 1 2 3 4 4% 6 2% 7  [ 29:akin@sgi.com ] Re: Future development of PEX/PHIGS]  [ 9:bthompso@reed] What is a good book for Digital Image Processing]  [ 15:csp48@seq1.ke] Help! ASCII picture needed…  [ 14:rcj2@cbnewsd.] Re: 3D igitizers… again  [240:raj@ms.uky.ed] Call For Papers -- ACM Multimedia 93204481 Foundation ofComputer Graphics March 7, 2013 8
    • 9. What is Computer Graphics ?  Computer graphics is commonly understood to mean the creation, st orage and manipulation of models a nd images. (Andries van Dam)  Computer graphic is concerned with  all aspects of producing pictures or images using a computer.  the pictorial synthesis or real or imaginary objects from their computer based model204481 Foundation ofComputer Graphics March 7, 2013 9
    • 10. Computer Graphics  Computer Graphics  Synthesis of graphical images  Visualization :  creating an image from an abstract, symbolic description.  Generation of Synthesis Image  using graphical primitives  data from real world phenomena204481 Foundation ofComputer Graphics March 7, 2013 10
    • 11. Image Processing  Image Processing  the transformation of an existing image into a more desirable or useful image.  image enhancement, pattern detection The following images represent how noise affects images204481 Foundation ofComputer Graphics March 7, 2013 11
    • 12. Image Analysis  Image Analysis (Computer Vision)  extracting symbolic information from the image. Computer Graphics Data => Picture Image Processing Picture => Picture204481Image Analysis of Foundation Picture => DataComputer Graphics March 7, 2013 12
    • 13. What is Interactive Computer Graphics?  User controls contents, structure, and appearance of objects and their displayed images via rapid visual feedback  Basic components of an interactive graphics system  input (e.g., mouse, tablet and stylus, force feedback device,scanner…)  processing (and storage)  display/output (e.g., screen, paper-based printer, video recorder…)204481 Foundation ofComputer Graphics March 7, 2013 13
    • 14. Why Computer Graphics? (1/5)  Humans communicate well with images  1/3 of your brain is devoted to visual processing  A picture is worth a few hundred megabytes204481 Foundation ofComputer Graphics March 7, 2013 14
    • 15. Why Computer Graphics? (2/5)  Developing Computational Capability  Rendering: synthesizing realistic-looking, useful, or interesting images  Animation: creating visual impression of motion  Image processing: analyzing, transforming, displaying images efficiently204481 Foundation ofComputer Graphics March 7, 2013 15
    • 16. Why Computer Graphics? (3/5)  Better Understanding of Data, Objects, Processes through Visualization  Visual summarization, description, manipulation  Virtual environments (VR), visual monitoring, interactivity  Human-computer intelligent interaction (HCII): training, tutoring, analysis, control systems204481 Foundation ofComputer Graphics March 7, 2013 16
    • 17. Why Computer Graphics? (4/5)  Time is Right  Recent progress in algorithms and theory  Rapidly emergence of new I/O (display and data acquisition) technologies  Available computational power, improving price- performance-ratio of hardware  Growth and interest of graphics industries (e.g., information visualization, entertainment CAD)204481 Foundation ofComputer Graphics March 7, 2013 17
    • 18. Why Computer Graphics? (5/5)  advances in the last decade due mostly to the microchip  software advances, especially in object-oriented programming and real-time rendering algorithms  Hardware advances continue to benefit graphics:  faster inexpensive microprocessors and dedicated graphics chips  screen technology: High-definition television (HDTV), colour LCD  virtual reality interfaces (corneal implants?)204481 Foundation ofComputer Graphics March 7, 2013 18
    • 19. Image Synthesis Pipeline Graphics Database Editing Front-End Graphics Database (Geometry Processing) Back-End Display Traversal Modeling Transformation Viewing Operation  (Rasterization) • Visible-Surface Determination • Scan Conversion Image • Shading / Illumination204481 Foundation ofComputer Graphics March 7, 2013 19
    • 20. A Brief History  teletype printouts were first graphical output devices lightpens were an early input device CAD applications beg an in the 1960s plotters also a 60s development: high-res olution, but slow main bottlenecks of computer graphics ba ck then  cost of graphics hardware  expense of computer resources batch systems werent suitable for interactive graphics non-portability of hardware and software a new field: technology was 204481 primitive Foundation ofComputer Graphics March 7, 2013 20
    • 21. History of Computer Graphics (1/5)  1950 MIT’s Whirlwind computer had computer generated CRTs mid 19 50s SAGE command an d control  1960s Ivan Sutherland’s thesis - Sketchpad  introduced data structures and interactive techniques http://www.computer.org/history/development/1951.htm204481 Foundation ofComputer Graphics March 7, 2013 21
    • 22. History of Computer Graphics (2/5)  1960s GM (general Motor)  developed CAD (Computer Aided Design) and CAM  1968 Tektronix storage tubes  1970s Boeing CAD CAM204481 Foundation ofComputer Graphics March 7, 2013 22
    • 23. History of Computer Graphics (3/5)  Mid 1970s engineering workstations and personal computers emerged separately  1980s new algorithms and techniques  new standards  ever more powerful system  transition from specialized field  1990s widespread use low cost, but powerful personal workstations   networks  essential part of systems  now part of multimedia204481 Foundation ofComputer Graphics March 7, 2013 23
    • 24. History of Computer Graphics (4/5) At first - progress was slow because  cost of equipment was high (specially memory)  significant computing resources needed  difficulty in writing software ( harder than it looks)  lack of standard and thus portability  lack of software tools204481 Foundation ofComputer Graphics March 7, 2013 24
    • 25. History of Computer Graphics (5/5) Now - previous use  cost of equipment is low.  Most computer have necessary computing resources for graphics  established standards, implementations and tools  still difficulty in writing software ( still harder than it looks)204481 Foundation ofComputer Graphics March 7, 2013 25
    • 26. Some of Historical Picture (1/2)  First truly interactive graphics system, Sketchpad, pioneered at MIT by Ivan Sutherland for h is 1963 Ph.D. thesis. Sketchpad , A Man-Machine Graphical Comm unication System:  Sketchpad in 1963. Note the use of a CRT monitor, light pe n and function-key panel.204481 Foundation ofComputer Graphics March 7, 2013 26
    • 27. Some of Historical Picture (2/2) http://www.man.ac.uk/Science_Engineering/CHSTM/nahc.htm John VonNeuman http://ei.cs.vt.edu/~history/VonNeumann.html Mark I204481 Foundation ofComputer Graphics March 7, 2013 27
    • 28. Applications of Computer Graphics Applications of Computer Graphics  divided in 4 majors area  Display of Information  Design  Simulation  User Interface204481 Foundation ofComputer Graphics March 7, 2013 28
    • 29. Display of Information  Geographic information system (GIS)  Computerized Tomography (CT)  Magnetic resonance http://www.soest.hawaii.edu/soest/about.ftp.html imaging (MRI)  Ultrasound  positron-emission tomography (PET)204481 Foundation of http://www.queens.org/qmc/services/imaging/ct.htmComputer Graphics March 7, 2013 29
    • 30. Design  Computer-Aided Design (CAD)  Architecture  Design of Mechanical part  VLSI  etc... http://www.memagazine.org/contents/current/features/push/push.html204481 Foundation ofComputer Graphics March 7, 2013 30
    • 31. Simulation  Graphical flight simulator  reduce training process  Robotic simulation The Concorde Panel.  TV, Movie, advertising industries  generate photo realistic images  Virtual Reality (VR)  reduce risk of training  surgery  astronaut204481 Foundation of http://www.motionshop.com/pr/festocosimirlg.shtmlComputer Graphics March 7, 2013 31
    • 32. User Interfaces  Window system  Window 2003  X window  MAC OS  Graphical Network browsers  Netscape  Internet Explorer204481 Foundation ofComputer Graphics March 7, 2013 32
    • 33. Areas of research in Graphics (1/2)  mathematical modeling:  interpolation, curve and surface fitting  computational geometry: algorithmic applications in geometry  study of light and optical phenomenon: colour, texture, shades  modelling the characteristics of physical objects (bouncing Jello)204481 Foundation ofComputer Graphics March 7, 2013 33
    • 34. Areas of research in Graphics (2/2)  Software technology  standardized graphics languages and libraries  graphics tools and interfaces  algorithm design  Hardware  specialized graphics chips, monitors, interface devices204481 Foundation ofComputer Graphics March 7, 2013 34
    • 35. Graphics Applications  Entertainment: Cinema Pixar: Geri’s Game Universal: Jurassic Park Antz204481 Foundation of A bug’s LifeComputer Graphics March 7, 2013 35
    • 36. Graphics Applications (1/4)  Entertainment: Games Aki Ross : Final Fantasy Star Wars Jedi Outcast: Jedi Knight II204481 Foundation of Quake IIIComputer Graphics March 7, 2013 36
    • 37. Graphics Applications (2/4)  Medical Visualization The Visible Human Project204481 Foundation of http://www.ercim.org/publication/Ercim_News/enw44/koenig.htmlComputer Graphics March 7, 2013 37
    • 38. Graphics Applications (3/4)  Computer Aided Design (CAD)204481 Foundation ofComputer Graphics March 7, 2013 38
    • 39. Graphics Applications (4/4)  Scientific Visualization204481 Foundation ofComputer Graphics March 7, 2013 39
    • 40. Hypermedia User Interfaces (1/2) NCSA D2K: http://chili.ncsa.uiuc.edu Visual programming system for high-performance knowledge discovery in databases (KDD)  Hypermedia  Database format (similar to hypertext) that provides display-based access to (internetworked) multimedia (text, image, audio, video, etc.) documents  Chimera: http://www.ics.uci.edu/pub/chimera/204481 Foundation ofComputer Graphics March 7, 2013 40
    • 41. Hypermedia User Interfaces (2/2)  Virtual Environments  Immersion: interactive training, tutoring systems  Entertainment hypermedia  Visualization and Computer- Aided Design and Engineering (CAD/CAE)  Visualization: scientific, data/information, statistics  User interfaces for CAD/CAE/CAM/CASE: http://www.isii.com http://www.psl.cs.columbia.edu/chime/204481 Foundation ofComputer Graphics March 7, 2013 41
    • 42. Curve and Surface Modeling 1 http://www.geocities.com/SiliconValley/Lakes/2057/nurbs.html 2 3 4 5 8 7 6204481 Foundation ofComputer Graphics March 7, 2013 42
    • 43. Photorealistic Illumination Models http://www.pixar.com http://www.ktx.com/3dsmaxr3/ http://www.aliaswavefront.com204481 Foundation ofComputer Graphics March 7, 2013 43
    • 44. Fractal Systems204481 Foundation of http://sprott.physics.wisc.edu/fractals.htmComputer Graphics March 7, 2013 44
    • 45. Information Visualization204481 Foundation of Visible Decisions SeeIT (http://www.vdi.com)Computer Graphics March 7, 2013 45
    • 46. Interesting Industrial Applications 6500 news stories from the WWW in 1997 Cartia ThemeScapes – http://www.cartia.com Hypermedia and Statistical Visualization Destroyed Normal Extinguished Ignited Fire Alarm Engulfed Flooding Virtual Environments for204481 Foundation of DC-ARM – http://www-kbs.ai.uiuc.edu Immersive TrainingComputer Graphics March 7, 2013 46
    • 47. Overview of Programmer’s Model (1/2)  Pixel - smallest addressable unit of display  Hardware (I/O)  output display device (normally raster scan)  on the order of a million pixels displayed  image stored in memory by pixel (how much memory?)  video controller  scans the memory periodically (30-72 times a second) produces video signal to drive a video monitor (or flat screen di splay)  input devices - keyboard, mouse (track ball), tablet, voice etc.204481 Foundation ofComputer Graphics March 7, 2013 47
    • 48. Overview of Programmer’s Model (2/2) Software  application data  application program  graphics interface  operating system204481 Foundation ofComputer Graphics March 7, 2013 48
    • 49. Graphical System And Standard (1/5)  Graphical Systems  High level language interface to graphical devices.  Intended for development of portable code.  Standard graphical systems include CORE,   Graphical Kernel System (GKS), GKS+  Programmers Hierarchical Interactive Graphics System (PHIGS), PHIGS+  OpenGL, DirectX, Quickdraw 3D, VRML, Open Inventor, X-Windows.204481 Foundation ofComputer Graphics March 7, 2013 49
    • 50. Graphical System And Standard (2/5)  Requirements of Graphical Systems  Portability  Device Independence Concept of a logical device.  Language Independence Language Bindings for graphical systems.  Computer Independence Trade-off between standard hardware and high performance hardware.  Programmer Independence  Flexibility - In conflict with portability.204481 Foundation ofComputer Graphics March 7, 2013 50
    • 51. Graphical System And Standard (3/5)  Graphical Kernel System (GKS)  Workstation  GKS has concept of a workstation.  Device Normalisation  World Coordinates, Window in World Coordinates  Clipping to the window  Normalised Device Coordinates [0,1]x[0,1]  Normalisation Transformation  Viewports in normalised device coordinates204481 Foundation ofComputer Graphics March 7, 2013 51
    • 52. Graphical System And Standard (4/5)  Output Functions  Line-Drawing Primitives  Area-filling primitives  Text Output  Input Functions  Logical input types : Locator, Valuator, Choice, String, Pick, Stroke.204481 Foundation ofComputer Graphics March 7, 2013 52
    • 53. Graphical System And Standard (5/5)  Input Modes  Request mode: waits for a request for an event.  Sample mode: continually samples value of input device.  Event mode: unsolicited input stored on a stack, made available for processing in FIFO order.  Mixed mode.204481 Foundation ofComputer Graphics March 7, 2013 53
    • 54. Professional Societies ACM SIGGRAPH - Association for Computing Machinery Special Interest G roup in Graphics IEEE - The Institute of Electrical and Electronics Engineers, Technical Committee on Co mputer Graphics204481 Foundation ofComputer Graphics March 7, 2013 54
    • 55. Software Portability and graphics standards STANDARD ORGANIZATION  ANSI = American National Standard Institute (private, non government)  ISO = International Standards Organization(voluntary, non treaty)  ANSI is a member of ISO204481 Foundation ofComputer Graphics March 7, 2013 55
    • 56. History: graphics libraries  initially, low-level device-dependent packages were the norm  movement towards high-level device- independent packages, in order to promote application program portability  requires standardization:204481 Foundation ofComputer Graphics March 7, 2013 56
    • 57. Official Standards  1977 and 1979 - 3D SIGGRAPH CORE (ACM SIGGRAPH)  3D Core Graphics System ("Core") devd in late 70s as unofficial std  GKS (Graphical Kernel System, 1985): official 2D standard built from Core  GKS-3D (1988): 3d objects ANSI X3.124-1985  PHIGS (Programmers Hierarchical Interactive Graphics System, 1988) 3D nested objects  PHIGS+ (1988): rendering enhancements204481 Foundation ofComputer Graphics March 7, 2013 57
    • 58. Emerging Standards in APIs  OpenGL (developed by Silicon Graphics)  open standard  available on all platforms  intended for professional-level graphics like CAD  Direct3D  developed by Microsoft  Windows only  intended for games204481 Foundation ofComputer Graphics March 7, 2013 58
    • 59. Some Notable Systems  Tektronix commands in BASIC (mid-1970s)  HP commands (Hewlett Packard)  Microsoft BASIC (for PCs) graphics commands (early 1980s)  QuickDraw (Apple Macintosh)  X (MIT)  OpenGL (Silicon Graphics)  SRGP (Simple Raster Graphics Package)  SPHIGS (Simple PHIGS)  MS Windows  Java AWT204481 Foundation ofComputer Graphics March 7, 2013 59
    • 60. Good graphics requires ? (1/3)  ability to control every dot (pixel) of display  ability to control primitive shapes on the screen  models to deal with images as a whole  use of color, lighting, and shading  construction of "languages" or "packages" to extend languages  knowledge of hardware  systems work204481 Foundation ofComputer Graphics March 7, 2013 60
    • 61. Good Graphics requires ? (2/3)  mathematical transformations and representations  transmission of pictures and commands to make pictures  ability to store lots of information  high performance computers  algorithms such as visible surface algorithms204481 Foundation ofComputer Graphics March 7, 2013 61
    • 62. Good Graphics requires ? (3/3)  understanding and manipulation of data structures  good software engineering principles  human factors engineering  some feeling for artistic principles  lots of effort - harder than it looks204481 Foundation ofComputer Graphics March 7, 2013 62
    • 63. Lecture Topics  Introduction Visible Surface  Mathematical Determination Foundation  Algorithm efficiency  Coordinate Systems  Z-buffer algorithm  Introduction to  Scan line algorithms Graphics in 2D  Visible-surface Ray Tracing  Windows and Clipping  Introduction to  Other algorithms Graphics in 3D  Color Models  Viewing in 3D  Illumination and Shading204481 Foundation ofComputer Graphics March 7, 2013 63
    • 64. Mathematical foundation  Mathematical appears throughout 3D graphics Example:  Object surfaces can be represented as polygons whose vertex position are specified by vectors  Rendering requires testing whether vertices lie in front of or behind various planes.  The test involves a dot product with the plane’s normal vector.204481 Foundation ofComputer Graphics March 7, 2013 64
    • 65. Geometric transformation  Goal: specify object’s position and orientations in a 3D world  Use Linear transformations that rotate and translate objects’ vertices.  Apply these transformations in matrix form204481 Foundation ofComputer Graphics March 7, 2013 65
    • 66. Viewing  Goal: map the visible part of a 3D world to a 2 D image  Use camera-like parameters to define a 3D view volume  Project the view voulme onto a 2D image plane  Map viewport on the image plane to the screen204481 Foundation ofComputer Graphics March 7, 2013 66
    • 67. OpenGL  OpenGL is strictly defined as “a software interface to graphics hardware”.  It is a 3D graphics and modeling library  variety purposes, CAD engineering, architectural applications, computer-genera ted dianosaurs in blockbuster movies  Developed by SGI204481 Foundation ofComputer Graphics March 7, 2013 67
    • 68. Clipping  Goal: cut off the part of objects outside the view volume to avoid rendering them204481 Foundation ofComputer Graphics March 7, 2013 68
    • 69. Scan Conversion  Goal: convert a project, clipped object into pixels on raster lines.  Use efficient incremental methods204481 Foundation ofComputer Graphics March 7, 2013 69
    • 70. Antialiasing  Raster displays produce blocky aliasing artifacts  Antialiasing techniques reduces the problem by applying the theory of sam pling and signal processing204481 Foundation ofComputer Graphics March 7, 2013 70
    • 71. Color  Various color spaces provide ways to specify colors in term of components:  red, green, blue  hue, saturation, value  Different output devices display different subsets of the perceptible col ors204481 Foundation ofComputer Graphics March 7, 2013 71
    • 72. Hidden Surface Removal  When several overlapping polygons are drawn on the screen, which one is on top? Which is right?204481 Foundation ofComputer Graphics March 7, 2013 72
    • 73. Z-buffering  A fast hardware solution is This pixel is drawn on the Z-buffer screen  The “depth” of each pixel relative to the screen is Screen calculated and saved in a Polygons buffer  The pixel with the smallest depth is the one that is displayed  The other pixels are on Z surfaces that are hidden204481 Foundation ofComputer Graphics March 7, 2013 73
    • 74. Lighting Models and Shading  For visual realism, lighting Ambient lighting: models have been developed to illuminate the surfaces of solid models  These models incorporate incident reflected light  ambient lighting and illumination light  diffuse reflection of directional lighting  specular reflection of directional reflected light incident lighting light204481 Foundation ofComputer Graphics March 7, 2013 74
    • 75. Ray Tracing Light Source Shadow Ray Eye Object Eye Ray Shadow Ray Object Light Source  Ray tracing traces a ray of light from the eye to a light source  Ray tracing realistically renders scenes with shiny and transparent204481 objects Foundation ofComputer Graphics March 7, 2013 75
    • 76. Radiosity  Diffuse illumination results from the absorption and reflection of diffuse light from many objects in the scene  Radiosity uses thermal models of emission and reflection of radiation to Radiosity is very good at accurately calculate rendering architectural interiors diffuse lighting204481 Foundation ofComputer Graphics March 7, 2013 76
    • 77. Texture Mapping  For realism, photographic textures are “mapped” onto the surfaces of objects  Example textures: texture mapping  woodgrain  concrete  grass reflections  marble shadows  Texture mapping is very computationally intensive204481 Foundation ofComputer Graphics March 7, 2013 77
    • 78. Example of Shading Wireframe Flat Shaded Smooth Shaded Shadows204481 Foundation ofComputer Graphics March 7, 2013 78