1 basics of computer graphics

Basics of Computer Graphics
Dheeraj S. Sadawarte
1Dheeraj S Sadawarte https://dheerajsadawarte.blogspot.com

Introduction
• Field of science concerned with digitally
synthesizing and manipulating the visual content.
– creating,
– Storing
– Displaying
– manipulating images
• Focus on mathematical & computational
foundations of image generations .
• Manipulation of visual & geometric information
using computational techniques.

Images and object
• Image is a representation of an object on a
computer
• Symbolic representation other than the text
• 2D array of data with values at each element
of the array related to a color
• Objects are real entities defined in 3D world
co-ordinates.

Image Representation
• Pictures are represented as a collection of
discrete picture element called PIXELS.
• It is the smallest addressable screen element.
• resolution is the number of pixels contained on
a display screen.
• It expressed in terms of the number of pixels on
the horizontal axis and the number on the
vertical axis.
• The process of determining the appropriate
pixels for representing pictures or objects is
called RASTERIZATION.

Rasterization and Scan Conversion
• Rasterization is the task of taking an image
described in a vector graphics format (shapes)
and converting it into a raster image (pixels or
dots) for output on a video display or printer,
or for storage in a bitmap file format
• Scan conversion: The process of representing
continuous pictures as graphical object(as a
collection of discrete pixel) is called scan
conversion.

Image Representation

Basic graphic pipeline
• Object in a real world are expressed with respect
to a world co ordinate system
• The world is then projected into a view plan from
a view point
• Z axis determines the view direction
• Window specifies the area of interest
• View volume is the infinite volume swept by the
rays
• Near and far clipping plane
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Dheeraj S Sadawarte
https://dheerajsadawarte.blogspot.com

Bitmap and vector based graphics
BITMAP (raster) VECTOR BASED
• Composed of pixels
• Created and edited in photo
or paint program
• Images are mapped to a grid
or an array of pixels
• Not easily scalable
• Used in photorealistic images
involves complex variation
• The larger we display a
bitmap, the jagged it appears
• Composed of paths
• Created and edited in
software like CoralDraw and
Adobe Illustrator
• Images have smooth edges
and create curves or shapes
• Good for precise illustrator
but not as good as bitmap
• Easily scalable due to the use
of mathematical formula
• A vector image remains
smooth in any size
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Dheeraj S Sadawarte

Application of computer graphics
• Special effects-illusions used in film, television industries
to simulate the imagined events in a story.
• Visual effects-involves integration of live-action footage
with computer generated elements in order to create
scenarios which look realistic.
• Digital art-an art created on a computer in a digital form
• Video games: gaming and animation industry
• Computer aided design-used by civil, mechanical &
electronic engineers to build the models of buildings,
bridges or circuit boards
• Medical imaging-used in molecular biology to study the
model of the genes
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Dheeraj S Sadawarte

Display device
• Display device is a device for presentation of
information such as images or a text for visual
display.
• Eg:CRT(Cathode ray tube)
• It is a specialized vacuum tube in which
images are produced when an electron beam
strikes a phosphorescent surface.
• Heat is supplied to the cathode by passing
current through a heater element. The
cathode is a cylindrical metallic structure
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Dheeraj S Sadawarte

Cathode Ray Tube
• Cathode ray tube:
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You can
Download the complete PPT from the following link
Dheeraj S Sadawarte
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