Chapter 3 : IMAGE

Objectives
• Discuss the various factors that apply to the use of
images in multimedia.
• Describe the capabilities and limitations of bitmap
images.
• Describe the capabilities and limitations of vector
images.
• Define various aspects of 3D modeling.
• Describe the use of colors and palettes in multimedia.
• Cite the various file types used in multimedia.

Overview
• Creation of multimedia images.
• Creation of still images.
• Colors and palettes in multimedia.
• Image file types used in multimedia.

Creation of multimedia imagesCreation of multimedia images
• Images obviously play a very important role in
multimedia products
– Images may be photograph-like bitmaps, vector-based drawings, or 3D
renderings
• The type of still images created depends on the
display resolution, and hardware and software
capabilities.
• Access to the right tools and right hardware for
image development is important!
– E.g., graphic designers like to have large, high-resolution monitors or
multiple monitors

Types of Still ImagesTypes of Still Images
Still images are generated in two ways:
– Bitmaps (or raster-based) .
– Vector-drawn graphics.

Bitmaps
• Bitmap is derived from the words ‘bit’, which means
the simplest element in which only two digits are
used, and ‘map’, which is a two-dimensional matrix
of these bits.
• A bitmap is a data matrix describing the individual
dots of an image that are the smallest elements
(pixels) of resolution on a computer screen or
printer.

Bitmaps
• Bitmaps are an image format suited for
creation of:
– Photo-realistic images.
– Complex drawings.
– Images that require fine detail.
• Bitmapped images are known as paint
graphics.
• Bitmapped images can have varying bit and
color depths.

Bitmaps
Available binary Combinations for
Describing a Color
• More bits provide more color depth, hence more photo-realism;
• but require more memory and processing power

• Monochrome just requires one bit per
pixel, representing black or white
BMP – 16 KB

• 8 bits per pixel allows 256 distinct colors
BMP – 119KB

• 16 bits per pixel represents 32K distinct colors (Most
graphic chipsets now supports the full 65536 colors
and the color green uses the extra one bit)
BMP – 234 KB

• 24 bits per pixel allows millions of colors
• 32 bits per pixel – trillion of colors
BMP – 350KB

• Bitmaps are best for photo-realistic images
or complex drawings requiring fine detail

• Bitmaps picture and their suitability of use:-
– Use the native Microsoft bmp format as a raw image that will later be
processed. It faster to process.
– Use JPEG, for photo sharing on the web because of its size and quality.
– GIF is normally used for diagrams, buttons, etc., that have a small number of colours
• It is also suitable for simple animation because it
supports interlaced images.
– PNG is almost equal to gif except that it didn’t support the animation format.

Bitmaps
Bitmaps can be inserted by:
– Using clip art galleries.
– Using bitmap software.
– Capturing and editing images.
– Scanning images.
Clip Art
CaptureScan
Drawn

Using Clip Art GalleriesUsing Clip Art Galleries
• A clip art gallery is an assortment of graphics, photographs,
sound, and video.
• Clip arts are a popular alternative for users who do not
want to create their own images.
• Clip arts are available on CD-ROMs and on the Internet.
• Legal rights :
1)1) Public domain imagePublic domain image
2)2) Royalty free imageRoyalty free image
3)3) Right Managed ImageRight Managed Image

Using Bitmap SoftwareUsing Bitmap Software
The industry standard for bitmap painting and
editing programs are:
• Adobe's Photoshop and Illustrator.Adobe's Photoshop and Illustrator.
• Macromedia's Fireworks.Macromedia's Fireworks.
• Corel's Painter.Corel's Painter.
• CorelDraw.CorelDraw.
• Quark Express.Quark Express.

Capturing and Editing ImagesCapturing and Editing Images
• Capturing and storing images directly from the
screen is another way to assemble images for
multimedia.
• The PRINT SCREENPRINT SCREEN button in Windows and
COMMAND-CONTROL-SHIFT-4COMMAND-CONTROL-SHIFT-4 keystroke on the
Macintosh copies the screen image to the
clipboard.
• Clipboard : a temporary memory to store the
COPY, CUTCOPY, CUT and PASTEPASTE data

Capturing and Editing ImagesCapturing and Editing Images
Image editing programs enable the user to:
– Enhance and make composite images.Enhance and make composite images.
– Alter and distort images.Alter and distort images.
– Add and delete elements.Add and delete elements.
– Morph (manipulate still images to create animatedMorph (manipulate still images to create animated
transformations).transformations).
High Resolution Image : based on dot per inch (dpi) & effect file size

High Resolution PhotoHigh Resolution Photo
High resolution photoHigh resolution photo
• A high resolution picture is determined
by its number of pixels; more pixels
improves the sharpness of the picture.
• This is print quality
Low resolution photoLow resolution photo
• Any pictures found on the web
normally are low resolution and not
suitable for print quality.
• A picture that is low-resolution cannot
be made into a high resolution photo

Scanning ImagesScanning Images
• Users can scan images from conventional
sources and make necessary alterations and
manipulations.

Example of MorphingExample of Morphing

ApplicationsApplications of Vector-Drawnof Vector-Drawn
ImagesImages
• Vector-drawn images - created from geometric
objects such as lines, rectangles, ovals, polygons
using mathematical formulas
• Vector-drawn images are used in the following areas:
– Computer-aided design (CAD) programs.
– Graphic artists designing for the print media.
– 3-D animation programs.
– Applications requiring drawing of graphic shapes.

HowHow Vector-Drawn Images WorkVector-Drawn Images Work
• A vector is a line that is described by the location oflocation of
its two endpoints.its two endpoints.
• Vector drawing makes use of Cartesian co-ordinatesmakes use of Cartesian co-ordinates.
• Cartesian coordinates are numbers that describe a
point in two or three-dimensional space as the
intersection of X, Y, and Z axis.
X
Y
Z

• Example
RECT 0,0,200,300,RED,BLUE says
– “Draw a rectangle starting at 0,0 (upper left corner of screen) going
200 pixels horizontally right and 300 pixels downward, with a RED
boundary and filled with BLUE.”
300
pixel
200 pixel

Vector-Drawn ImagesVector-Drawn Images v/sv/s
BitmapsBitmaps
• Vector images use less memory space and
have a smaller file size (.svg) as compared to
bitmaps.
• For the Web, pages that use vector graphics in
plug-ins download faster, and when used for
animation, draw faster than bitmaps.

• Vector images cannot be used for
photorealistic images.
• Vector images require a plug-in for Web-
based display.
• Bitmaps are not easily scalable and resizable.
• Bitmaps can be converted to vector images
using autotracing.
Vector-Drawn ImagesVector-Drawn Images v/sv/s
BitmapsBitmaps

3-D Drawing and Rendering3-D Drawing and Rendering
• 3D graphics tools, such as Macromedia
Extreme3D, or Form-Z, typically extend
vector-drawn graphics in 3 dimensions (x, y
and z)
X
y
Z

• A 3D scene consist of object that in turn contain many
small elements, such as blocks, cylinders, spheres or
cones (described in terms of vector graphics)
• The more elements, the finer the object’s resolution and
smoothness.

• Objects as a whole have properties such as
shape, color, texture, shading & location.
• A 3D application lets you model an object’s
shape, then render it completely.

Features of a 3-D ApplicationFeatures of a 3-D Application
1. Modeling involves drawing a shape, such as a 2D letter,
then extruding it or lathing it into a third dimension.
– extruding : extending its shape along a defined path
– lathing : rotating a profile of the shape around a
defined axis

• Modeling also deals with lighting, setting a
camera view to project shadows

2.Rendering : produces a final output of a
scene and is more compute-intensive.

3-D Animation Tools3-D Animation Tools
3-D animation, drawing, and rendering tools
include:
– Ray Dream Designer.Ray Dream Designer.
– Caligari True Space 2.Caligari True Space 2.
– Specular Infini-D.Specular Infini-D.
– Form*Z.Form*Z.
– NewTek's Lightwave.NewTek's Lightwave.

Natural Light and ColorNatural Light and Color
• Light comes from an atom where an electron passes from a
higher to a lower energy level.
• Each atom produces uniquely specific colors.
• Color is the frequency of a light wave within the narrow band
of the electromagnetic spectrum, to which the human eye
responds.
• Eye can differentiate 80,000 different colors.
• Color and Culture
• Color and Emotion

Color and CultureColor and Culture
COLOR CHINA JAPAN EGYPT FRANCE UNITED
STATE
Red Happiness Anger
Danger
Death Aristocracy Danger
Stop
Blue Heavens
Clouds
Villainy Virtue
Faith
Truth
Freedom
Peace
Masculine
Green Ming
Dynasty
Heavens
Future
Youth
Energy
Fertility
Strength
Criminality Safety
Go
Yellow Birth
Wealth
Power
Grace
Nobility
Happiness
Prosperity
Temporary Cowardice
Temporary
White Death
Purity
Death Joy Neutrality Purity

Color and EmotionColor and Emotion
EMOTION COLOR EMOTION COLOR
Happy Yellow Inexpensive Brown
Pure White Powerful Red
Good Luck Green Dependable Blue
Good Red High Quality Black
Dignity Purple Nausea Green
High Technology Silver Deity White
Sexiness Red Bad Luck Black
Mourning Black Favorite Color Blue
Expensive Gold Least Favorite Color Orange

Computererized ColorComputererized Color
• The tools we use to describe color are different when the
color is printed than from when it is projected
• 2basic method of making color
– Additive
– Subtractive
ColorColor

Additive ColorAdditive Color
• In the additive color method, a color is
created by combining colored light sources in
three primary colors - red, green, and blue
(RGB).
• OLD TV and computer monitors use this
method.

Subtractive ColorSubtractive Color
• In the subtractive color method, color is
created by combining colored media such as
paints or ink.
• The colored media absorb (or subtract) some
parts of the color spectrum of light and reflect
the others back to the eye.

Subtractive ColorSubtractive Color
• Subtractive color is the process used to create
color in printing.
• The printed page consists of tiny halftone dots
of three primary colors- cyan (complement of
Red), magenta (complement of Green), and
yellow (Complement of Blue) (CMY).

Monitor-Specific ColorsMonitor-Specific Colors
• Colors should be used according to the target
audience's monitor specifications.
• The preferred monitor resolution is higher
1024x768 pixels and higher.
• The preferred color depth is 24 bits or more
which can display 16,777,216 different colors .

Computer Color ModelsComputer Color Models
• Different ways of representing information
about color.
• Models used to specify color in computer
terms are:
– RGB model - A 24-bit methodology where color is specified in terms of red,
green, and blue values ranging from 0 to 255.
– HSB and HSL models – Color is specified as an angle from 0 to 360 degrees on
a color wheel.
– Other models include CMYK, CIE, YIQ, YUV, and YCC.

RGB ModelRGB Model
 Add red, green and blue to create colors, so it is an
additive model.
 Assigns an intensity value to each pixel ranging from
0 (black) to 255 (white)
 A bright red color might have R 246, G 20, B 50

RGB Color ModelRGB Color Model

HSB and HSL Color ModelsHSB and HSL Color Models
• Based on human perception of color, three
fundamental properties of color:
– Hue – angle of 0 -360 degrees
– Saturation – intensity of color (%)
– Brightness / Lightness - relative lightness or
darkness of color (%)

HSB and HSL Color ModelsHSB and HSL Color Models
• Hue - color reflected from or transmitted
through an object, measured on color wheel

HSB and HSL ColorModelHSB and HSL ColorModel
• Saturation (or chroma) - strength or purity
of color (% of grey in proportion to hue)

HSB ModelHSB Model
• Brightness - relative lightness or darkness of
color, also measured as %
Black white
0% 50% 100%

CMYK ModelCMYK Model
• Based on light-absorbing quality of ink printed on
paper
• As light is absorbed, part of the spectrum is
absorbed and part is reflected back to eyes
• Associated with printing; called a modsubtractive
model
• Four channels: Cyan (C ), magenta (M), yellow (Y)
and black (K)
 In theory, pure colors should produce
black, but printing inks contain impurities,
so this combination produces muddy
brown
 K is needed to produce pure black, hence
CMYK is four-color process printing

Color PalettesColor Palettes
• Palettes are mathematical tables that
define the color of pixels displayed on
the screen.
• Palettes are called ‘color lookup tables’
or CLUTs on Macintosh.
• The most common palettes are 1, 4, 8,
16, and 24-bit deep.

DitheringDithering
Dithering:
– Dithering is a process whereby the color value of
each pixel is changed to the closest matching
color value in the target palette.
– This is done using a mathematical algorithm.

Dithering
Original Picture Undeterred Picture Deterred Picture

Image File Types used inImage File Types used in
MultimediaMultimedia
• Macintosh formats.
• Windows formats.
• Cross-platform formats.

Macintosh FormatsMacintosh Formats
• On the Macintosh, the most commonly used
format is PICT.
• PICT is a complicated and versatile format
developed by Apple.
• Almost every image application on the
Macintosh can import or export PICT files.

Windows FormatsWindows Formats
• The most commonly used image file format on
Windows is DIB or known as BMP.
• DIB stands for Device-independent bitmaps.

Bitmap formats used most often by Windows
developers are:
– BMP - A Windows bitmap file.BMP - A Windows bitmap file.
• Native bitmap file format of the Microsoft Windows
environment
– TIFF - Extensively used in DTP packages.TIFF - Extensively used in DTP packages.
• Used to exchange documents between different
applications and platforms
– PCX - Used by MS-DOS paint software.PCX - Used by MS-DOS paint software.
• One of the oldest bitmapped formats popularized by
MS-DOS paint programs that first appeared in the early
1980's

Cross-Platform FormatsCross-Platform Formats
The image file formats that are compatible
across platforms are:
• DXF, IGS or IGES - Used by CAD applications.
• CDR – CorelDraw, PSD – Photoshop n AI - Illustrator
• JPEG, PNG and GIF - Most commonly used formats on
the Web.

Most Popular Image File FormatsMost Popular Image File Formats
• JPEG (Joint-Photographic Experts Group)
• GIF (Graphical Interchange Format)
• PNG (Portable Network Graphic)
• Other formats:
–BMP, PSD, TIFF/TIF, TGA, EPS, PCX,
ICO

• JPEG
– For continuous tone images, such as full-color
photographs
– Supports more than 16 millions of color (24-bit)
– Uses lossy compression (averaging may lose
information)

• GIF
– For large areas of the same color and a moderate
level of detail.
– Supports up to 256 colors
– Allows transparency and interlacing
– Uses lossless compression

• PNG
 lossless, portable, well-compressed storage of
raster images
 patent-free replacement for GIF
 also replace many common uses of TIFF
 Support indexed-color, grayscale, and true color
images + an optional alpha channel for
transparency

Information DeliveryInformation Delivery
 Images or Graphics are used to convey information in
multimedia products.
 For example, a picture of an automobile engine is much
more effective than text that merely describes it.

 Images or Graphics for information delivery include:
 Drawn images
 Charts and graphs
 Maps
 Scenery
 People

 In each case, the image must be relevant to the overall
product.
 Image size, color in respect to the application and other
images, and positioning must all be considered when using
images.

SummarySummary
• The computer generates still images as
bitmaps and vector-drawn images.
• Images can be incorporated in multimedia
using clip arts, bitmap software, or by
capturing, editing, or scanning images.
• Creating 3-D images involves modeling,
extruding, lathing, shading, and rendering.
• Color is one of the most vital components of
multimedia.

Chapter 3 : IMAGE

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