Module 1:Introduction to Computer Graphics
Que: Define Computer graphics.
Ans: Computer graphics is defined
as generation and editing of 2D or 3D images with the help of computer.
Que: Enlist and Explain applications of Computer graphics.
Ans:
1) Games and
entertainment: Computer graphics is used for the development of computer
games or mobile games. Also, computer graphics is used for creation and editing
of Movies, TV programs. Few movies totally created using computer graphics only
and in few movies some scene modified by adding special effects or animations.
2)Scientific
Visualization: Scientists or engineers are using computer-based models for
analyzing huge amount of data. Also, scientific models like solar system, galaxy,
black hole are used for education purpose.
3)Medical
visualization: Computer based Medical models like cut section of human
body, brain, DNA structure can be used for visualizing minute details from it.
Such models are used for education and training purpose.
4) Special
Effects: it is an illusion
created in movies or games using computer graphics. Today almost all movies contain
special effects to make it more presentable and attractive.
5) Art: Computer
graphics specialized software’s are used for painting, drawing of images and 3D
sculpture creation.
6) Computer
Aided Design (CAD/CAM/CAE): Computer Aided Design methods are used for
design and Analysis of Automobile, Aircraft, Buildings, Spacecrafts etc.
7)Data
Visualization: Today lots of data generated from markets, weather, banks,
sports etc. That data is represented on Computer screen using graphs, charts, plots.
8)Image
Processing: Image processing is used to improve, change or analyzing images
where Computer graphics is used for creation of images. Mostly both are used together.
Input Devices:
- Keyboard:
It is used to give input as numbers, strings and special characters.
- Mouse:
Motion of mouse translated as position on display.
- Scanner:
It optically scans printed material like documents, images and converted
into digital image.
- Joystick:
used to control movements in video games as input device. It selects screen
position with stick movement.
- Trackball:
it is 2D pointing device which detects movement based on rotating ball and
sensors.
- Space ball:
It provides six degree of freedom.
Output Devices:
- Displays: it is Visual Display Unit or Monitor to show information in pictorial form.
- Printers: It accepts text or picture data from computer and prints on paper as hard copy.
- Plotters: It draws picture on paper using pen based on instructions. It can be 2D plotter or 3D Plotter.
Que: Define pixel,aspect ratio,raster,scan line,frame buffer and size of screen.
Computer monitor is made up of
small discrete element i.e. pixel. We are drawing line or image on monitor by
glowing pixels which are part of line or image.
Pixel: it is smallest integer addressable location on display.
Pixel is also known as Pel or Picture element. Pixel on the screen have location
as (x, y).
Scan Line: Row of pixels is called scan line.
Raster: it is an array of pixels on the screen.
Aspect Ratio: Aspect ratio is ratio of width of the screen as to
height of screen. Standard aspect ratios are 4:3, 16:9 , 21:9.
Size of Display: Size of display is measured along diagonal in
inches.
Frame buffer: It is temporary storage just behind display which
have current pixel information in terms of gray scale or color to be displayed
on screen.
 |
| Monitor properties |
Que:Compare Raster Scan and Random Scan Displays
Raster Scan Display
|
Random Scan Display
|
The
beam will move from top to bottom scanning one line at a time
|
The
beam will move between endpoints of graphics primitive.
|
Raster
scan can draw any complex graphics
|
Raster
scan only draws lines and characters
|
Scan
Conversion is required.
|
Scan
conversion is not required
|
Cost
is Low
|
Cost
is more
|
Que: Explain working of CRT and Color CRT monitor.
CRT Monitor:
•CRT:
Cathode Ray Tube
•Electron
gun emits electron beam .
•Focusing
system converge electron beam to small spot when it strike to phosphorous
coating.
•Vertical and horizontal deflection systems controls
movement of beam in horizontal and vertical direction.
•Phosphorous
coating creates bright spot when
electron beam strike on it.
 |
| CRT monitor |
Color CRT Monitor:
•Three
Electron Guns: red, green and blue.
•Combined
resultant color of three colors is perceived by viewer.
 |
| Color CRT Monitor |
Que:Explain Raster Scan and Random Scan Architecture with block Diagram.
Architecture
of Raster Scan System
• It has special purpose processor as video controller
which is used to control operation of display device.
• Frame
buffer is a temporary storage which stores what to display at that time on
monitor.
• Video controller access frame buffer to refresh
screen.
 |
| Raster Scan System Architecture |
•Graphics commands from application program
translated into display file by graphics package.
• Display file is stored in system memory.
• Display Processor refreshes Screen using display
file.
• Graphics can be drawn by directly directing
electron beam along the components of graphics.
 |
| Random Scan System Architecture |
