# INTRODUCTION TO COMPUTERS

## Full text

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### TEXT AND REF. BOOKS

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Text Book:

Peter Norton (2011), Introduction to Computers, 7 /e, McGraw-Hill

Reference Book:

Gary B (2012), Discovering Computers, 1/e, South Western

Deborah (2013), Understanding Computers, 14/e, Cengage Learning

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### Learning Outcome

 What Are Computer Graphics  Types Of Computer Graphics  Raster & Vector Graphics

 Types Of Images, Size, Compression & Formats  Cartesian Coordinate System

 Acquiring Images  Graphics Software

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### Types of Computer Graphics

 Two types of computer graphics

 Raster Graphics

 Raster graphics are composed of pixels

 Uses a grid of individual pixel, each pixel can be a

different color & shade, Commonly called bitmap images

 Best used for photographs and images

 Is an array of multicolor pixels those form an image

 Blocks images because each pixel increases the size of

the image.

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### Types of Computer Graphics

 Vector Graphics

 Vector graphics are generated with paths

 Use mathematical relationships between points &

the paths connecting them to describe an image

 Appear smooth at any size or resolution  Every path comprises of lines that may be

straight or curved

 Vector graphics can be scaled without losing the

image quality.

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### There are two types of images,

 2 Dimensional (2D)

 2D is used to create flat digital images  X and Y, horizontal and vertical axis

(Length, Width)

 2D graphics are used for printing and

Drawing applications

 2D graphics are vector based graphics.

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### 3 Dimensional (3D)

 3 dimensional representations of geometric

data, such as length, width and depth

 Use X, Y and Z axis to represent the image

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### coordinates

 The axes in 2D are X and Y

 The axes in 3D are X, Y and Z

 The origin in 2D is (0,0)

 The origin in 3D is (0,0,0)

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Image file size is positively correlated to the

 number of pixels in an image  color depth, or bits per pixel

 For example, a 640 * 480 pixel image with 24-bit

color would occupy almost a megabyte of space

 640 * 480 * 24 = 7,372,800 bits  = 921,600 B

### Image File Size

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Lossless Compression File size is reduced while preserving a perfect copy of the original uncompressed image

Lossy Compression Algorithms preserve a representation of the original uncompressed image that may appear to be a perfect copy, but it is not

 Lossy compression is able to achieve smaller file sizes

than lossless compression

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### File formats and compatibility

 Method for storing an image

 Hundreds of image file formats

 Each method has pros and cons

 Some formats are proprietary

 Graphic software can handle all formats

 Separated into the two main families of

graphics: Raster and Vector

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### Raster Formats

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 JPEG / JFIF

  Lossy compression method

 Significant reduction of the file size

 JPEG (Joint Photographic Experts Group)

compressed images are usually stored in

the JFIF (JPEG File Interchange Format) file format

  Filename extension is JPG or JPEG

 JPEG files suffer generational degradation when

repeatedly edited and saved

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### JPEG 2000

 Compression standard enables both lossless

and lossy storage

 Different from the standard JFIF/JPEG

 Improve quality and compression

 Require more computational power to process

 Used currently in professional movie editing

and distribution

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### Jpeg 2000

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 EXIF (Exchangeable image file format)

 Similar to the JFIF format with TIFF extensions

 Record and standardize the exchange of images with

meta data between digital cameras and editing sw

 camera settings, time and date, shutter speed, exposure,

image size, compression, name of camera, color information

### Raster Format

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 TIFF (Tagged Image File Format)

 Can be lossy and lossless

 Format is not widely supported by web browsers

 Widely accepted as a photograph file standard in the printing business

 OCR (Optical Character Recognition) software packages commonly generate some form of TIFF

image for scanned text pages

### Raster Format

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 RAW (Raw Image Format)

 Available on some digital camera

 Usually use a lossless or nearly lossless

compression

 File sizes smaller than the TIFF formats

 Yet to be standardized or documented

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### (Graphics Interchange Format)

 Limited to an 8-bit palette, or 256 colors

 GIF format suitable for storing graphics with

relatively few colors

 Simple diagrams, shapes, logos and

cartoon style images

 Format supports animation and is still

widely used

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### PNG (Portable Network Graphics)

 Free, open-source alternative to GIF

 PNG file format supports

 8 bit paletted images  24 bit truecolor

 48 bit truecolor

 Designed to work well in online viewing applications

 Lossless compression

### Raster Format

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 BMP (Windows Bitmap)

 Handles graphics files within the Microsoft

Windows OS

 BMP files are uncompressed with simple structure  Large size and lossless

 Image is drawn using a pixel grid  Each grid contains a color

 Used to store drawings or photographs  Resizing image can reduce quality

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NOTHING

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COFFIN

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### 

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He was wearing his Uniform 

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WINDOW 

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### 

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She was walking 

### but didn't break the law.

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 Most vector formats are proprietary

 Three universal formats exist

 DXF (Drawing eXchange Format)

 IGES (Initial Graphics Exchange Specification)

 Both format used by AutoCAD (a software use to

create, modify, analyze or optimize a design) users

### Vector File Formats

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 SVG (Scalable Vector Graphics)

 An open standard

 Developed by the World Wide Web Consortium

 Versatile, scriptable and all-purpose for WWW

 No compression scheme

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### Scanners

 Like a photocopier

 Image is saved onto disk

 Scanners import a variety of formats

 Ex JPG/JPEG, TIFF, PDF etc

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### Digital cameras

 Stores digitized images

 Uses long term storage

 Image is usually a JPG file

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### Digital video cameras

 Stores full motion video

 Uses long term storage

 Movie can be transferred to

DVD

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### Clip Art

 Originally a book with images

 Now a CD with images

 Most office suites include a

selection

 Additional clip art is online

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### Paint programs

 Create bitmap images

 Includes sophisticated tools

 Artists draw with several brushes

 Objects drawn become

permanent

 Windows Paint

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### Draw programs

 Create vector based images

 Used when accuracy is critical

 Objects have an outline and fill

 Both have line style and color  Can fill using pictures

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### Photo-Editing software

 Modify and manipulate digital images

 Work at the pixel level

 Images can be enhanced

 Picture flaws can be repaired

 Pictures can be completely changed

 Photoshop and GIMP

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### GNU Image Manipulation Program

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 Generates vector files

 Engineering and design fields

 Drawings accurate to the

millimeter

### Graphics Software

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 3D modeling software

 Generates three dimensional images

 Image can be shaped on screen

 Image is animated frame by frame

 AutoCAD, Autodesk 123D, Art of Illusion (Free +

Osource) etc

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### Computer generated imaging

 Generates photo realistic images

 Used for movies and television

 Software eliminates tedious parts

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### Exercise : PowerPoint

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 Create a Power Point presentation that contains:

 Minimum five slides

 First slide must contain “Title” of your presentation topic, your

name; roll number, batch and department.

 The next slide must contain Introduction about the selected topic  Last slide must contain “Conclusion”

 Use bullets to include text in the slides  Your slides must have slide number.

 Make use of Transitions and Slide Layout

 Apply an animation effect using the options in the Animation

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## Any Questions !!!

END OF LECTURE 4

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M 

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STOP IMAGEINING 

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His Mother 

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Letter “N” 

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### 57

Surgeon was His Mother 

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## References

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