1

TOPICS TO BE COVERED

• Introduction to Computer Graphics

• Applications

• Graphics Hardware

• Input Devices

• Hard Copy Devices

2

APPLICATIONS– Computer Aided Design

– Presentation Graphics

– Entertainment

– Education and Training

– Visualization

– Image Processing

– Graphical User Interfaces

3

COMPUTER AIDED DESIGN

• Circuit Drawings

• Real-time Animations

• Virtual-Reality Environments

• Architectural Drawings

4

Credit: MICHAEL WESTFALL, MARTECH TECHNICAL SERVICES; FAIRFIELD, CA Date Created: 10/6/97 Software: AutoCAD and 3D Studio Max

A Magic VLSI Layout System

COMPUTER AIDED DESIGN

5

COMPUTER AIDED DESIGN

Credit: MIKE JUSTICE, UNIVERSITY OF MIAMI

SCHOOL OF ARCHITECTUREDate Created: 1/5/1999

Software: AutoCAD and 3D Studio Max R2

Towards Virtual Manufacturing

6

PRESENTATION GRAPHICS

• Presentation Graphics is representing descriptions and facts using graphs.

• Various Graphs such as Piechart, bargraphs line charts are used.

• Used to summarize financial, statistical, mathematical, scientific data etc.

7

ENTERTAINMENT

• Motion Pictures

• Music Videos

• Television Shows

• Games

8

EDUCATION AND TRAINING

• Computer Graphics is almost used in every field to teach and train

• Medicine• Human Anatomy Models

• Engineering• Animated Models : Explaining the working of

different models

• Fashion Designing• Designing and Creating new Patterns

9

VISUALIZATION

• Scientific Visualization• Business Visualization• Computer graphics makes vast quantities of data accessible.

• Numerical simulations frequently produce millions of data values.

• Similarly, satellite-based sensors amass data at rates beyond our abilities to interpret them by any other means than visually.

• Mathematicians use computer graphics to explore abstract and high-dimensional functions and spaces.

• Physicists can use computer graphics to transcend the limits of scale.

10

IMAGE PROCESSING

• Manipulating images with a computer • Image processing generally involves three steps:

– Import an image with an optical scanner or directly through digital photography.

– Manipulate the image in some way. This stage can include image enhancement and data compression.

• For example: Image processing can be used to reduce the noise (that infernal spec that comes from nowhere) in an image. – Output the result. The result is the image altered in some way.

 

11

GRAPHICAL USER INTERFACES

• Computer graphics is an integral part of every day computing.

• Nowhere is this fact more evident than the modern computer interface design.

• Graphical elements such as windows, cursors, menus, and icons are so common place it is difficult to imagine computing without them.

• Once graphics programming was considered a specialty.

• Today, nearly all professional programmers must have an understanding of graphics in order to accept input and present output to users

12

INPUT DEVICES• Keyboards• Mouse• Trackball• Spaceball• Joysticks• Data Glove • Digitizers• Image Scanners• Touch Panels• Light Pens• Voice Systems

13

KEYBOARD

Keyboard

Ergonomic KeyboardDesigned to help prevent cumulative trauma disorder (CTD) or damage to nerve tissues in the wrist and hand due to repeated motion

Cordless Keyboard

14

MOUSE•

Operating a mechanical mouse.1 Moving the mouse turns the ball.2 X and Y rollers grip the ball and transfer movement.3 Optical encoding disks include light holes.4 Infrared LEDs shine through the disks.5 Sensors gather light pulses to convert to X and Y velocities.

15

Optical Mouse1. Surface-independent

2. Uses an optoelectronic sensor to take successive pictures of the surface on which the mouse is operating.

3. Most of these mice use LEDs to illuminate the surface that is being tracked

16

1. In 2004, Logitech, along with Agilent Technologies, introduced the laser mouse

2. Uses a small laser

Wireless Mouse

17

Trackball

• A pointing device

• CAD workstations for ease of use

• Some clip onto the side of the keyboard and have integral buttons which have the same function as mouse buttons.

• Trackballs are sometimes seen on computerized special-purpose workstations, such as the radar consoles in an air-traffic control room or sonar equipment on a ship or submarine.

18

SPACEBALL

1. 6 degrees of freedom input device2. Developed by 3DConnexion. 3. Designed to ease navigation in 3D computer

models. 4. Major used by CAD and computer graphics

professionals

19

JOYSTICK

1. General control device consisting of a

handheld stick that pivots about one end and

transmits its angle in two or three dimensions

2. Available as Two-dimensional and 3D

3. 2D having two axes of movement

4. In three-dimensional movement, twisting the

stick left (counter-clockwise) or right

(clockwise) signals movement along the Z

axis. 28

20

• Touch panels are– pressure-sensitive (resistive)– electrically-sensitive (capacitive),– acoustically-sensitive (SAW – surface acoustic

wave) – photo-sensitive (infra-red).

TOUCH PANELS

21

DATA GLOVE• Equipped with sensors that sense the movements of the

hand and interfaces those movements with a computer.

• Commonly used in virtual reality environments where the

user sees an image of the data glove and can

manipulate the movements of the virtual environment

using the glove

22

DIGITIZERS1. A computer peripheral device that allows one to

hand-draw images directly into a computer,

generally through an imaging program.

2. They consist of a flat surface upon which the user

may "draw" an image using an attached stylus, a

pen-like drawing apparatus.

3. The image generally does not appear on the tablet

itself but, rather, is displayed on the computer

monitor.

4. It is interesting to note that the stylus, as a

technology, was originally designed as a part of the

electronics, but later it simply took on the role of

providing a smooth, but accurate "point" that would

not damage the tablet surface while "drawing".

23

IMAGE SCANNER• Scanner is a device that analyzes a physical image (such as a

photograph, printed text, or handwriting) or an object (such as an

ornament) and converts it to a digital image.

• Types of Scanner Available

– desktop (or flatbed) scanner

– Hand-held scanners,

• Both these types of scanners use a charge-coupled device (CCD) as the

image sensor

– drum scanner uses a photomultiplier tube as the image sensor.

24

LIGHT PEN1. Computer input device in the form of a light-sensitive wand used in conjunction with the computer's

CRT monitor.

2. It allows the user to point to displayed objects, or draw on the screen, in a similar way to a touch screen but with greater positional accuracy.

3. It can work with any CRT-based monitor, but not with LCD screens, projectors or other display devices.

4. Fairly simple to implement.

5. It works by sensing the sudden small change in brightness of a point on the screen when the electron gun refreshes that spot.

6. By Noting exactly where the scanning has reached at that moment, the X,Y position of the pen can be resolved.

7. This is usually achieved by the light pen causing an interrupt, at which point the scan position can be read from a special register, or computed from a counter or timer. The pen position is updated on every refresh of the screen.

25

First Light Pen

This handmade prototype of a "light gun" in 1952 was part a Project at MIT.

LIGHT PEN

26

VOICE SYSTEMS

• The Voice system input can be used to initiate graphics operations to enter data

• Microphone is such designed to minimize input of other background sounds

• Words as spoken by the operator is stored so as to analyze and recognize the speech pattern.

27

HARD-COPY DEVICES

– Impact Printers• Dot-Matrix Printer (Character Based)

– Non-Impact Printers• Laser Printer• Ink- jet Printer• Electrostatic device• Plotters

– Flatbed – Drum Plotter

28

IMPACT PRINTER• Dot-matrix printers

– Low cost devices– Produce noise – Speed, resolution and color quality are generally poor,– Dot-matrix printers are often satisfactory for drafts or in-house

presentations.– Typical resolution 80-120 dpi

29

Non-Impact PrintersLaser printers• Good quality paper and OHP transparency output at 300 dpi• Reasonable speed, • Costly than DMP• Being a raster device it can integrate text (permitting many

typefaces) with graphics and raster images Dots of electrostatic charge deposited on drum, picks up toner (black powder form of ink) and is rolled on to paper , which is then fixed with heat.

• Typically 600dpi or better. • These printers are also called page printers as they print one page

at a time

30

• A color raster device that is becoming ever more popular, which creates images by transferring colored wax to paper.

• It is a high quality hardcopy device supported by many software packages in the areas of presentation graphics, graphics design, image processing, solid modeling and scientific visualization.

• Depending upon the interface connection, large image files can take a considerable time to transmit and process. It is a multi pass device with a nominal resolution of 300 dpi

Thermal Transfer Printers

31

• These printers use heat sensitive paper that alters color when heated. Paper is heated by pins where a dot is required. Usually one line of dots created per pass

Thermal Printer

32

Ink Jet Printers• Generally, these devices are not capable of

reproducing the output quality, versatility or efficiency of laser and thermal printers, but are popular with personal computer users for immediate hardcopy output.

• The capital cost is low and the consumable costs are tolerable: somewhat more expensive than the laser printer for mono, but less than the thermal printer for color.

• The number of colors varies from around 300 for low-cost devices to full color for high-end 'prepress' printers.

• These printers use one or more nozzles in printhead to emit a steady stream of tiny ink drops.

Non-Impact Printers

33

• This hardcopy device offers full color output similar to photographic quality.

• Capital cost is high, and consumable cost is also high, ranging from 2 pounds (in-house) up to 20 pounds (commercially).

Thermal Dye Sublimation Printers

34

Plotters

1. A device that draws pictures on paper based on commands from a computer.

2. Vector graphics printing device 3. Plotters differ from printers in that they draw lines

using a pen.4. As a result, they can produce continuous lines,

whereas printers can only simulate lines by printing a closely spaced series of dots.

5. Multicolor plotters use different-colored pens to draw different colors.

6. In general, plotters are considerably more expensive than printers. They are used in engineering applications where precision is mandatory.

35

• Drum plotter draws on paper wrapped around a drum

which turns to produce one direction of the plot, while the

pens move to provide the other direction

• A flatbed plotter draws on paper placed on a flat surface

• An Electrostatic plotter draws on negatively charged

paper with positively charged toner.

Plotters