INTRODUCTION Computer Graphics 1 INTRODUCTION: THE OUTLINE I. - - PowerPoint PPT Presentation

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INTRODUCTION Computer Graphics 1 INTRODUCTION: THE OUTLINE I. - - PowerPoint PPT Presentation

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INTRODUCTION Computer Graphics 1 INTRODUCTION: THE OUTLINE I. Image Processing / Computer Graphics II. Advantages III. Representative Uses IV. Classification of Applications V. History VI. Conceptual Framework VII. Our First Assignment 2

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1

Computer Graphics

INTRODUCTION

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SLIDE 2

INTRODUCTION: THE OUTLINE

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  • I. Image Processing / Computer Graphics
  • II. Advantages
  • III. Representative Uses
  • IV. Classification of Applications
  • V. History
  • VI. Conceptual Framework
  • VII. Our First Assignment
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  • I. IMAGE PROCESSING / COMPUTER GRAPHICS

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  • Image Processing:
  • Analysis and reconstruction of existing images
  • Sub-Areas:
  • Image Enhancement
  • Pattern Detection and Recognition
  • Scene Analysis
  • Computer Vision
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  • I. IMAGE PROCESSING

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SLIDE 5

IMAGE ENHANCEMENT

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Apex Sharpening of Andromeda Galaxy Image http://math.nist.gov/mcsd/highlights/carasso-spie06.html

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PATTERN DETECTION AND RECOGNITION

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Body parts detection for people tracking using trees of Histogram of Oriented Gradient descriptors, http://hal.inria.fr/INRIA/inria-00496980/en/

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SLIDE 7

SCENE ANALYSIS

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The Vision and Mobile Robotics Laboratory, http://www.cs.cmu.edu/~vmr/jobs/jobs.html

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SLIDE 8

COMPUTER VISION

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Software That Evaluates Facial Expressions , http://www.sciencedaily.com/videos/computers_math/internet/5/

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  • I. IMAGE PROCESSING / COMPUTER GRAPHICS

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  • Computer Graphics:
  • Synthesis of new images
  • Overlap between the two is

growing

  • William Latham,

Evolutionary Art

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SLIDE 10
  • II. ADVANTAGES

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  • Communication between user and computer
  • Interactive graphics
  • Creation of abstract, synthetic objects
  • Not confined to static images: animation
  • User controlled dynamics
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  • III. REPRESENTATIVE USES

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  • User Interfaces
  • Interactive Data Plotting
  • Office Automation / Electronic

Publishing

  • Computer-Aided Drafting and

Design

http://www.warmelin.com/cad-cam.html

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SLIDE 12
  • III. REPRESENTATIVE USES

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  • Simulation and Animation
  • Scientific
  • Entertainment
  • Art and Commerce
  • Process Control
  • Cartography
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  • IV. CLASSIFICATION OF APPLICATIONS

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  • Dimensionality
  • Kind of Picture
  • Type of Interaction
  • Role of the Image / Graphic
  • Relationship between Objects and Pictures
  • Logical
  • Temporal
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DIMENSIONALITY: 2D AND 3D

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http://www.media-freaks.com/articles/3d-animation-studios-what-goes-on-behind-those-closed-doors

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KIND OF PICTURE: LINE DRAWING / WIREFRAME

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Grand Designs 3D Software

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KIND OF IMAGE: COLOR / GRAYSCALE

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TYPE OF INTERACTION

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  • Offline Plotting
  • Interactive Plotting
  • User Moves Around (or within) Object
  • Interactive Object Design
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ROLE OF THE IMAGE / GRAPHIC

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  • Picture as End Product
  • Cartography
  • Drafting
  • Artwork
  • Animation
  • Picture as Means to an End
  • CAD/CAM
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SLIDE 19
  • V. HISTORY

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  • Beginnings
  • Crude Plotting
  • Sutherland 1963
  • Sketchpad
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  • V. HISTORY

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  • Output Technology
  • Vector Display
  • Oscilloscopes were some of the 1st computer displays
  • Computation results used to drive the vertical and horizontal axis (X-Y)
  • Intensity could also be controlled (Z-axis)
  • Used mostly for line drawings
  • Display list had to be constantly updated

(except for storage tubes)

  • Raster Display
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  • V. HISTORY

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  • Output Technology
  • Vector Display
  • Raster Display

Raster

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SLIDE 22
  • V. HISTORY

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  • Input Technology
  • Light Pens
  • Mouse, Tablet, Touch Screen, Audio
  • Kinect
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  • V. HISTORY

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  • Software
  • Device Dependent – Device Independent
  • Program Portability
  • Programmer Portability
  • Standards
  • Core
  • GKS and GKS-3D
  • PHIGS and PHIGS+
  • Industry Standards (as opposed to official standards)
  • OpenGL (SGI)
  • Java-2D and Java-3D (Sun)
  • DirectX (Microsoft)
  • X-Windows (MIT/Unix/Linux)
  • …
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SLIDE 24
  • VI. CONCEPTUAL FRAMEWORK

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Graphics System/ GPU Application Model/data base

Software Hardware

Application program Graphics Library

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  • VI. CONCEPTUAL FRAMEWORK

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  • Application Model
  • Application Database
  • Property Information
  • Created by:
  • Application Program
  • User Interaction
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  • VI. CONCEPTUAL FRAMEWORK

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  • Application Program
  • Translation of the Model to Graphics Commands
  • Database Traversal
  • Translation to Geometric Primitives
  • User Interaction Handling
  • Sampling vs. Event Driven
  • Event Loop Model
  • State and Screen Update vs. State, Screen and

Database Update

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SLIDE 27
  • VI. CONCEPTUAL FRAMEWORK

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  • Application Program
  • Two Basic Paradigms: Sample-Based and Geometry-Based
  • Sample-based graphics: discrete samples are used to describe visual

information

  • pixels can be created by digitizing images, using a sample-based

“painting” program, etc.

  • often some aspect of the physical world is sampled for visualization, e.g.,

temperature across the US

  • example programs: Adobe Photoshop™, GIMP™ , Adobe AfterEffects™
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SLIDE 28
  • Images are made up of grid of discrete

pixels, for 2D “picture elements”

  • Pixels are point locations with

associated sample values, usually of light intensities/colors, transparency, and

  • ther control information
  • Samples created directly in paint-type

program, or as sampling of continuous (analog) visual materials

  • Sample values can also be input

numerically

  • Once an image is defined as pixel-

array, it can be manipulated via:

  • Image editing
  • Image processing

SAMPLE-BASED GRAPHICS

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SLIDE 29

SAMPLE-BASED GRAPHICS

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  • Advantages:
  • Once image is defined in terms of colors at (x, y)

locations on grid, can change image easily by altering location or color values

  • Pixel information from one image can be copied

and pasted into another, replacing or combining with previously stored pixels

  • Disadvantages:
  • WYSIAYG (What You See Is All You Get):
  • no depth information
  • can’t examine scene from different point of view
  • at most can play with the individual pixels or

groups of pixels to change colors, enhance contrast, find edges, etc.

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SLIDE 30

GEOMETRY-BASED GRAPHICS

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  • Geometry-based graphics (also called scalable vector

graphics or object-oriented graphics)

  • Store mathematical descriptions, or “models,” of geometric

elements (lines, polygons, polyhedrons…) and associated attributes (e.g., color, material properties).

  • Images created as pixel arrays (via sampling of geometry) for

viewing, but not stored as part of model. Images of many different views are generated from same model

  • Users cannot usually work directly with individual pixels in

geometry-based programs; as user manipulates geometric elements, program resamples and redisplays elements

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SLIDE 31

GEOMETRY-BASED GRAPHICS

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  • Modeling
  • Create models
  • Apply materials to models
  • Place models around scene
  • Place lights in scene
  • Place the camera

MODELING VS. RENDERING

  • Rendering
  • Take “picture” with camera
  • Both can be done with commercial software:
  • Autodesk MayaTM,3D Studio MaxTM,

BlenderTM, etc.

Directional Light Ambient Light Point Light Spot Light

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  • VI. CONCEPTUAL FRAMEWORK

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  • Graphics Library
  • Graphics Subroutine Library or Package
  • Intermediary between Application and Display Hardware
  • Examples: OpenGL™, DirectX™, Windows Presentation Foundation™ (WPF),

RenderMan™

  • Primitives (characters, lines, polygons, meshes,…)
  • Attributes
  • Color, line style, material properties for 3D
  • Lights
  • Transformations
  • Immediate mode vs. retained mode
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SLIDE 33
  • VI. CONCEPTUAL FRAMEWORK

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  • Graphics System / GPU
  • Logical Display Device
  • User Interaction
  • Modification of Model and/or Image
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SLIDE 34

OUR FIRST ASSIGNMENT

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THE CODE

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import static com.jogamp.opengl.GL4.*; import java.nio.FloatBuffer; import javax.swing.JFrame; import com.jogamp.common.nio.Buffers; import com.jogamp.opengl.*; import com.jogamp.opengl.awt.*; @SuppressWarnings("serial") public class Code extends JFrame implements GLEventListener { private GLCanvas myCanvas; public Code() { setTitle("Chapter2 - program1"); setSize(600,400); setLocation(200,200); myCanvas = new GLCanvas(); myCanvas.addGLEventListener(this); getContentPane().add(myCanvas); setVisible(true); } public void display(GLAutoDrawable drawable) { GL4 gl = (GL4) GLContext.getCurrentGL(); float bkg[] = { 1.0f, 1.0f, 0.0f, 1.0f }; FloatBuffer bkgBuffer = Buffers.newDirectFloatBuffer(bkg); gl.glClearBufferfv(GL_COLOR, 0, bkgBuffer); } public static void main(String[] args) { new Code(); } public void init(GLAutoDrawable drawable) {} public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {} public void dispose(GLAutoDrawable drawable) {} }

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SLIDE 36

SUMMARY

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  • I. Image Processing / Computer Graphics
  • II. Advantages
  • III. Representative Uses
  • IV. Classification of Applications
  • V. History
  • VI. Conceptual Framework
  • VII. Our First Assignment