Computer Graphics & Designs

8/2/2019 Computer Graphics & Designs

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PRESENTED BY:

KSHITIJ DIXIT

NEHA KACKER

RADHIKA ARORA

RICHA KAPOOR SHASHANK CHAUHAN


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COMPUTER AIDED DESIGN A major use of computer graphics is in designprocesses, particularly for engineering andarchitectural systems, but almost all products are

now computer designed. Generally referred to asCAD, computer aided design methods are nowroutinely used in the design ofbuildings,automobiles,aircraft,watercraft,spacecraft,

computers,textiles,and many, many other products.


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PRESENTATION of GRAPHICS Another major application area is presentationgraphics, used to produce illustrations for repots orto generate 35-mm slides or transparencies for use

with projectors. Presentation graphics commonlyused to summarize financial, statistical,mathematical, scientific, and economic data forresearch reports, managerial reports, consumer

information bulletins, and other types of reports.


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EntertainmentComputer graphics methods are now commonlyused in making motion pictures, music videos, andtelevision shows. Sometimes the graphics scenes are

displayed by themselves, and sometimes objects arecombined with the actors and live scenes.


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EDUCATION AND TRAININGComputer-generated models of physical, financial,and economic systems are often used as educationalaids. Models of physical systems, physiological

systems, population trends or equipment, such asthe color-coded diagram in fig 1-41, can help traineesto understand the operation of the system.


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VISUALISATIONScientists, engineers, medical personnel, businessanalysts, and others often need to analyze largeamounts of information to study the behavior of

certain processes. Similarly, satellite cameras andother sources are amassing large data files fasterthan they can be interpreted. Scanning these largesets of numbers to determine trends and

relationships is a tedious and ineffective process. Butif the data are converted to a visual form, the trendsand patterns are often immediately apparent.


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Due to the widespread recognition of the power and utility

of computer graphics in virtually all fields, a broad range of

graphics hardware and software systems is now available.For higher quality applications, we can choose from a

number of sophisticated special purpose graphics hardware

systems and technologies. Some of them are as follows:-


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VIDEO DISPLAY DEVICESTypically, the primary output device in a graphics

system is a video monitor (fig 2-1). The operation of

video monitor is based on the standard cathode ray

tube (CRT) design, but several other technologies existand solid-state monitors may eventually predominate.


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REFRESH CATHODE-RAYTUBES

A beam of electrons emitted by an electron gun, passes

through focusing and deflection systems that direct the

beam toward specified positions on the phosphor-coatedscreen. The phosphor then emits a small spot of light at

each position contacted by the electron beam. Because the

light emitted by the phosphor fades very rapidly. One way

to keep the phosphor growing is to redraw the picturerepeatedly by quickly directing the electron beam back over

the same points. This type of display is called a refresh CRT.


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RASTER- SCAN DISPLAYSThe most common type of graphics monitor employing a

CRT is the raster scan display, based on television

technology. In a raster scan system, the electron beam is

swept across the screen, one row at a time from top to

bottom. As the electron beam moves across each row, the

beam intensity is turned on and off to create a pattern of

illuminated spots .Picture definition is stored in a memory

area called the refresh buffer. This memory area holds the

set of intensity values for all the screen points. Stored

intensity values are then retrieved from the refresh buffer

and painted on the screen one row at a time (fig2-7).

Each screen point is referred to as a pixel.


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COLOR CRT MONITORSA CRT monitor displays color pictures by using a

combination of phosphors that emit different-colored light.

By combining the emitted light from the different

phosphors, a range of colors can be generated. The two

basic techniques for producing color displays with a CRT are

the beam penetration method and the shadow-mask

method.


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FLAT-PANEL DISPLAYSThe term flat-panel displays refers to a class of video

devices that have reduced volume, weight, and power

requirements compared to a CRT. A significant feature of

flat-panel displays is that they are thinner than CRTs, and

we can hang them on walls or wear them on our wrists.

Current uses of flat panel displays include small TV

monitors, calculator, pocket video games, laptops

computers, armrest viewing of movies on airlines, as

advertisement boards in elevators, etc.


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PLASMA PANEL DISPLAYPlasma panels, also called gas discharge displays, are

constructed by filling the region between two glass plates

with a mixture of gases that usually includes neon. A series

of vertical conducting ribbons is placed on one glass panel,

and a set of horizontal ribbons is built into the other glass

panel (fig 2-11). Firing voltages applied to a pair of

horizontal and vertical conductors cause the gas at the

intersection of the two conductors to break down into

glowing plasma of electrons and ions. Picture definition is

stored in a refresh buffer, and the firing voltages are applied

to refresh the pixel positions 60 times per second.


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LIQUID-CRYSTAL DISPLAYS(LCDS)

The term liquid crystal refers to the fact that these

compounds have a crystalline arrangement of molecules,

yet they flow like a liquid. They are commonly used in smallsystems, such as calculators (fig. 2-14) and portable, laptops

computers (fig.2-15).


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RASTER-SCAN DISPLAYPROCESSOR

The organization of a raster system containing a separatedisplay processor, sometimes referred to as a graphics

controller or a display coprocessor. The purpose ofthe display processor is to free the CPU from thegraphics chores. In addition to the system memory, aseparate display-processor memory area can also be

provided.


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INPUT DEVICESVarious devices are available for data input on a graphicsworkstation. Most systems have a keyboard and one ormore additional devices specially designed forinteractive input these include a mouse and digitizer.Some other input devices used in particular applicationsare data glove, touch panels, image scanners, and lightpen.


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KEYBOARDAn alphanumeric keyboard on a graphics system is usedprimarily as a device for entering text strings. Thekeyboard is an efficient device for inputting such non-graphic data as picture labels associated with a graphicsdisplay. Keyboards can also be provided with features tofacilitate entry of screen coordinates, menu selections,or graphics functions.


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MOUSEA mouse is small hand-held box used to position the screencursor. Wheels or roller on the bottom of the mouse can beused to record the amount and direction of movement .another method for detecting mouse motion is with an

optical sensor. For these system ,the mouse is moved over aspecial mouse pad that has a grid of horizontal and verticallines . the optical sensor detects movement across the lines inthe grid.


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IMAGE SCANNERSDrawings, graphs, color and black and white photos, ortext can be stored for computer processing with animage scanner by passing an optical scanningmechanism over the information to be stored. The

gradations of gray scale or color are then recorded andstored in an array. Once we have the internalrepresentation of a picture, we can applytransformations to rotate, scale or crop the picture to a

particular screen area. We can also apply various image-processing methods to modify the array representationof the picture.


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LIGHT PENFigure 2-56 shows the design of one type of light pen.Such pencil-shaped devices are used to select screenpositions by detecting the light coming from points onthe CRT screen. They are sensitive to the short burst oflight emitted from the phosphor coating at the instantthe electron beam strikes a particular point. Other lightsources such as background lighting the room, areusually not detected by a light pen.


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DESIGN OF ANIMATIONSEQUENCES

In general, an animation sequence is designed with thefollowing steps:

Storyboard layout

Object definitions

Key-frame specifications

Generation of in-between frames


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STORYBOARD LAYOUTThe storyboard is the outline of the action. It defines asthe motion sequence as a set of basic events that are totake place. Depending on the type of animation to beproduced, the storyboard could consist of a set of roughsketches or it could be a list of the basic ideas for themotion.


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OBJECT DEFINITIONSAn object definition is given for each participant in theaction. Objects can be defined in terms of basic shapes,such as polygons or splines. In addition, the associatedmovements for each object are specified along with theshape.


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Key-frame specifications A key frame is a detailed drawing of the scene at acertain time in the animation sequence. Within each keyframe, each object is positioned according to the time forthat frame. Some key frame is chosen at extremepositions in the action; others are spaced so that thetime interval between key frames is not too great.


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GENERATION OF IN-BETWEEN FRAMES

In-betweens are the intermediate frames between thekey frames. The number of in-betweens needed is

determined by the media to be used to display theanimation. Film requires 24 frames per second, andgraphics terminals are refreshed at the rate of 30 to 60frames per second.


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RASTER ANIMATIONSOn raster systems, we can generate real-time animationin limited applications using raster operations. Two-dimensional rotations in multiples of 90 are also simpleto perform, although we can rotate rectangular blocks ofpixels through arbitrary angles using antialiasingprocedures. To rotate a block of pixels, we need todetermine the percent of area coverage for those pixelsthat overlap the rotated block.


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MULTIMEDIAMultimedia means that the computer information canbe represented through audio, video and animation inaddition to traditional media (that in text, graphics,drawing and images) however the general definition ofmultimedia is as follows, Multimedia is a fieldconnected with the computer controlled,integration of text, graphics drawing, moving,images(video),audio, animation, and any othermedia where every type of information can berepresented, stored, transmitted and processeddigitally.


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Component of Multimedia

The Alphabets, words, sentences and paragraphsconsists of text. Text processing refers to the ability tomanipulate words, lines and pages. There are someproperties of any text such as size, font, color and style.

Text:


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A picture or image is data represented in two

dimensional scenes. A digital image compared of pixelsarrange in rectangular array with a certain height and width. Each pixel may contain one or more bits ofinformation representing the brightness of the image at

the point and possibly including color information andencoded as RGB triples.

GRAPHICS (PICTURE/IMAGES)


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Audio:Sound with in an aromatic range available to human. On

a computer an audio files are record of captured soundthat can be play back. Audio files are usually compressedfor storage purpose or faster transmission.


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Video:It refers to displaying still images in a high speed that

our mind interrupts the sequences of images as amovement. You can compare it with the number offrames/second i.e. higher with video with animation.


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Animation:The animation is the stimulation of movements created

by displaying the series of pictures or frames. A cartoonmovie on T.V. is the example of animation. Animationcan be made with special technique like flash and withimage application like photo-shop.


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APPLICATIONS OFMULTIMEDIA

Multimedia in business: The multimedia in businessincludes presentation, training, marketing, advertising,product demo and database.

Voice mail:Here we can communicate by the voice only bysending the voice in the form of electronic pulse from onesystem to another system, which converts it into voice.

Multimedia in education: Multimedia is also useful ineducational field. The computer generated modal of thephysical, financial and economical systems can be used as theeducational purpose.


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Multimedia of public sector: It is obvious thatpersonal places and public places are not awaiting to the multi

media. The public place cannot be beyond the reach of themultimedia such that the multimedia used in hotelsreservation, shopping and department store.

Virtual Realities: The multimedia is used in the CAD

application, circuit designing and stimulation of vehicles and itis used in the games.


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DVD TECHNOLOGYDVD initially stood for digital video disk but now standsfor digital versatile disk. Like a CD, DVD is an opticalstorage system for read only, recordable and writeableapplication but being similar to the CD in many ways.DVD is considered to be a CD future replacement.

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Computer Graphics & Designs