C9234 COMPUTER GRAPHICS

1. Define Computer graphics.Computer graphics is a sub-field of computer science which studies methods for

digitally synthesizing and manipulating visual content. Although the term often refers to thestudy of three-dimensional computer graphics, it also encompasses two-dimensional graphicsand image processing.

2. Define piel.!iel is shortened form of picture element. "t is the smallest discrete component of an

image or picture on a C#$ screen. %ach screen point is referred to as piel or pel.

  &. 'hat is bitmap(A raster graphics image or bitmap is a data structure  representing a generally

rectangular  grid of piels, or points of color , viewable via a monitor , paper , or other displaymedium. 

). 'hat is resolution(#esolution is the number of   piels contained on a display monitor, epressed in terms

of the number of piels on the horizontal ais and vertical ais. "t can be also referred asmaimum number of points that can be displayed without overlap on a C#$. $he sharpnessof the image on a display depends on the resolution and the size of the monitor.

  *. Define #andom scan and #aster scan displays.#andom scan is a method in which the display is made by the electronic beam which

is directed only to the points or part of the screen where the picture is to be drawn.#aster scan system is a scanning techni+ue in which the electrons sweep from top to

 bottom and from left to right. $he intensity is turned on or off to light and unlight the piel.

  . 'rite two techni+ues for producing color displays with a C#$.eam penetration method and shadow mas method.

  /. 'hat is a video controller("t is a special purpose controller, which is used to control the operation of the display

device. A fied area of the system is reserved for the frame buffer, and the video controller isgiven direct access to the frame buffer memory.

0. 'hat is frame buffer(A frame buffer is a video output device that drives a video display from a memory

 buffer containing picture definition. $he information in the buffer typically consists of colorvalues for every piel on the screen.

  . 'hat is beam penetration method($he beam-penetration method is an inepensive way for displaying color pictures has

 been used with random-scan monitors. $wo layers of phosphor, usually red and green, arecoated onto the inside of the C#$ screen, and the displayed color depends on how far theelectron beam penetrates into the phosphor layers.

1. 'hat is shadow mas method(3hadow-mas methods are commonly used in raster-scan systems which has three

 phosphor color dots 4red, green and blue5 at each piel position. $his type of C#$ has threeelectron guns, one for each color dot, and a shadow-mas grid 6ust behind the phosphor-coated screen.

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11. 'hat is run length encoding(#un length encoding is a compression techni+ue used to store the intensity values in

the frame buffer, which stores each scan line as a set of integer pairs. 7ne number each pairindicates an intensity value, and second number specifies the number of ad6acent piels onthe scan line that are to have that intensity value.

12. 'hat is 8CD(%lectronic device comprising of the molecules of a semi-li+uid material sandwiched

 between sheets of a transparent material. $he molecules are oriented by an electric currentapplied to them, and reflect light of different colors according to their orientation. "t is usedmainly in computer monitors and handheld devices such as cell phones and digital cameras,8CD usually consume very little current and have long service life.

1& . 8ist out the merits and demerits of D93$(Merits

• "t has a flat screen• #efreshing of screen is not re+uired

  De-merits

• 3elective or part erasing of screen is not possible• "t has poor contrast• !erformance is inferior to the refresh C#$.

1). 8ist out the merits and demerits of !lasma panel display(Merits

•   :#efreshing is not re+uired•   :!roduce a very steady flicer free image•   :8ess buly than a C#$

Demerits

•   :!oor resolution of up to dpi•   :"t re+uires comple addressing and wiring•   :"t is costlier than C#$

1*. 'hat is aspect ratio($he ratio of vertical points to the horizontal points necessary to produce length of

lines in both directions of the screen is called the aspect ratio.

1. 'hat is #egion Code("n Cohen-3utherland line clipping algorithm, every line end point in a picture is

assigned a four-digit binary code, called a region code, which identifies the location of the point relative to the boundaries of the clipping rectangle.

it 1 ; 8eftit 2 ; #ightit & ; elowit ) ; Above

1/. 'hat are the advantages and disadvantages of DDA algorithm(Advantages

• <aster method for calculating piel positions• %liminates the multiplication operations

Disadvantages

• Accumulation of round off error • #ounding operations and floating point arithmetic are time consuming

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10. 'hat is clipping(Any procedure that identifies portions of a picture that are either inside or outside of a

specified region of space is referred to as a clipping algorithm or simply clipping 1. 8ist down types of clipping.

!oint clipping, line clipping, area clipping, tet clipping and curve clipping

2. 8ist down the techni+ues used in tet clipping.• All or none string clipping• All or none character clipping• $et clipping

21. 'hich of the algorithm cohen sutherland algorithm or liang barsy algorithm is moreefficient Algorithm( 'hy(

8iang-arsy algorithm is more efficient than the cohen-sutherland algorithm, sinceintersection calculations are reduced. %ach updates of parameters =1 and =2 re+uires only onedivision> and window intersection of the line computed only once, when the final values of=1and =2 have been computed.

1. 'hat is $ransformation($ransformation is the process of introducing changes in the shape size and orientation

of the ob6ect using scaling rotation reflection shearing ? translation etc.

2. 'hat is translation($ranslation is the process of changing the position of an ob6ect in a straight-line path

from one coordinate location to another. %very point 4 , y5 in the ob6ect must under go adisplacement to 4@,y@5. the transformation is; @ B t > y@ yBty

&. 'hat is rotation(A 2-D rotation is done by repositioning the coordinates along a circular path, in the -

y plane by maing an angle with the aes. $he transformation isgiven by; @ r cos 4+ B f5 and y@ r sin 4+ B f5.

). 'hat is scaling(A 2-D rotation is done by repositioning the coordinates along a circular path, in the y

 plane by maing an angle with the aes. $he transformation is given by; @ r cos 4+ B f5 andy@ r sin 4+ B f5.

*. 'hat is fied point scaling($he location of a scaled ob6ect can be controlled by a position called the fied point

that is to remain unchanged after the scaling transformation.

. 'hat is shearing($he shearing transformation actually slants the ob6ect along the direction or the

direction as re+uired. ie> this transformation slants the shape of an ob6ect along a re+uired plane.

/. 'hat is reflection($he reflection is actually the transformation that produces a mirror image of an ob6ect.

<or this use some angles and lines of reflection.

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0. 'hat is antialiasing($he process of ad6usting intensities of the piels along the line to minimize the effect

of aliasing is called antialiasing.

. Distinguish between uniform scaling and differential scaling('hen the scaling factors 3 and 3y are assigned to the same value, a uniform scaling is

 produced that maintains relative ob6ect proportions. =ne+ual values for 3 and 3y result in adifferential scaling that is often used in design application.

1. 8ist the logical classification of input devices.87CA$7# device ; device for specifying coordinate positions3$#7E% device ; device for specifying a series of coordinate positions3$#"FG device ; device for specifying tet input9A8=A$7# device ; device for specifying scalar valueCH7"C% device ; device for selecting menu options!"CE device ; device for selecting picture components

11. 'hat are three modes for input devices(  $hree input modes are referred to as re+uest mode, sample mode, and event mode.

12. 'hat is a polygon(!olygons are small individual 2D shapes defined by verte which ordered in specific

way in &D space can produce comple &D ob6ects. Iore detailed &D ob6ects are defined fromof thousands of polygons.

1&. 'hat is conve and concave polygons(A polygon is conve if all interior angles are below 10 degree.A polygon is concave if at least one of its interior angle is greater than 10 degree.

1). Fame the different methods used for splitting a concave polygon(4i5 %dge vector cross product method4ii5 #otational method.

1*. Define forward and bacward rendering.$he direction of rendering describes how the relation between the &D scene and the

viewport is determined. 'ith forward rendering points in the scene are pro6ected on theviewport. "n bacward rendering, for each piel in the viewport a calculation is made todetermine what influence is of different points on the color and intensity of the screen piel.

1. 'hat is bezier curve(A ezier curve is a mathematically defined curve used in two-dimensional graphic

applications. $he curve is defined by four points; the initial position and the terminating position 4which are called JanchorsJ5 and two separate middle points 4which are calledJhandlesJ5. $he shape of a ezier curve can be altered by moving the handles

1/. 'hat are the important properties of ezier Curve(• "t needs only four control points• "t always passes through the first and last control points• $he curve lies entirely within the conve half formed by four control points

10. 'hat is a spline($o produce a smooth curve through a designed set of points, a fleible strip called

spline is used. 3uch a spline curve can be mathematically described with a piecewise cubic

)

 

 polynomial function whose first and second derivatives are continuous across various curvesection.

1. 'hat are the different ways of specifying spline curve(• =sing a set of boundary conditions that are imposed on the spline.• =sing the state matri that characterize the spline• =sing a set of blending functions that calculate the positions along the curve path

 by specifying combination of geometric constraints on the curve

2. 'hat is window and view port(A window defines a rectangular area in world coordinates.A viewport  defines in normalized coordinates a rectangular area on the display devicewhere the image of the data appears

1. Define !ro6ection($he process of displaying &D into a 2D display unit is nown as pro6ection. $he

 pro6ection transforms &D ob6ects into a 2D pro6ection plane

2. 'hat is meant by differential scaling(3caling transformation alters the size of an ob6ect. $he scaling factors 3 and 3y scales

ob6ects in the and y direction. 'hen 3  and 3y are assigned different values 43 K 3y5 itis called different scaling.

&. 'hat is 9iew plane($he plane onto which an ob6ect is pro6ected in a parallel or perspective pro6ection

). 'hat is parallel pro6ection("n parallel pro6ection, the observer position is at an infinite distance, so the pro6ection

lines are considered parallel. $his techni+ue is used in engineering and architectural drawingsto represent an ob6ect with a set of views that maintain relative proportions of the ob6ect

*. 'hat is perspective pro6ection("n a perspective pro6ection, ob6ect positions are pro6ected onto the view plane along

lines which converge at the observer, or Centre of !ro6ection 4C7!5. 3cenes displayed using perspective pro6ections appear more realistic, since images are formed similarly in humaneyes and a camera lens.

. 'hat is !ro6ection reference point("n !erspective pro6ection, the lines of pro6ection are not parallel. "nstead, they all

converge at a single point called !ro6ection reference point.

/. Differentiate perspective and parallel pro6ection.Perspective:

• visual effect is similar to human visual system...• has Lperspective foreshorteningL• size of ob6ect varies inversely with distance from the center of pro6ection.• angles only remain intact for faces parallel to pro6ection plane.

Parallel:

• less realistic view because of no foreshortening• however, parallel lines remain parallel.• angles only remain intact for faces parallel to pro6ection plane

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0. 'hat are the two principle types of parallel pro6ection.(Orthographic : direction of pro6ection is e+ual to normal to the pro6ection plane.Oblique : direction of pro6ection is not e+ual to normal to the pro6ection plane

 . 'rite short note on classification of visible surface detection methods.9isible-surface detection algorithms are broadly classified according to whether 

they deal with ob6ect definitions directly or with their pro6ected images. $hese twoapproaches are called ob6ect-space methods and image-space methods, respectively.

An 7bject-Space Method compares ob6ects and parts of ob6ects to each other withinthe scene definition to determine which surfaces, as a whole should label as visible.

"n an "mage-Space Algorithm, visibility is decided point by point at each piel position on the pro6ection plane.

1. 8ist few surface detection methods• ac-<ace Detection• Depth-uffer Iethod 4M-uffer Iethod5• A-uffer Iethod• 3can-8ine Iethod• Depth-3ort Iethod• inary 3pace !artitioning43!5 $ree Iethod• Area-subdivision Iethod• 7ctree Iethod• #ay-Casting Iethod

11. 'hat is the use of color looup tables($here are several advantages in storing color codes in a looup table.

4i5 =se of color table can provide a reasonable number of simultaneous color withoutre+uiring large frame buffers.

4ii5 Color table entries can be changed at any time allowing a user to be able toeperiment easily with different color combination.

12. 8ist different color models.• #G• H83• CI• H39• "N

1&. Define animation.3imulation of movement created by displaying a series of pictures, or frames

1). 'rite down the steps in designing an animation se+uence.• 3tory oard layout• 7b6ect definitions• Eey-frame specifications• Generation of in-between frame

1*. 'hat is ey frame(A ey frame is a detailed drawing of the scene at a certain time in the animation

 

se+uence. 'ithin each ey frame, each ob6ect is positioned according to the time for thatframe.

1. 'hat is tweening("t is the process, which is applicable to animation ob6ects defined by a

se+uence of points, and that change shape from frame to frame.

1/. Define Iorphing.$ransformation of ob6ect shapes from the form to another is called morphing, which is

a shortened form of metamorphosis. Iorphing methods can be applied to any motion ortransition involving a change in shape.

10. Define forward and bacward rendering.$he direction of rendering describes how the relation between the &D scene and the

viewport is determined.'ith forward rendering points in the scene are pro6ected on the viewport. "n bacward

rendering, for each piel in the viewport a calculation is made to determine what influence isof different points on the color and intensity of the screen piel.

1. 'hat is inematics or dynamic description of animation(Animation can be specified with motion parameters 4position, velocity, and

acceleration5 without giving reference to the forces that cause the motion. "t is calledinematics or dynamic description of animation. <or constant velocity 4zero acceleration5, wedesignate the motions of rigid bodies in a scene by giving an initial position and velocityvector for each ob6ect.

2. Define depth curing.A simple method for indicating depth with wire frame displays is to vary the intensity

of ob6ects according to their distance from the viewing position. $his is nown as depthcuring.

1. Define IultimediaIultimedia is the use of the computer to present and combine tet, graphics, audio

and video with lins and tools that lets the user to navigate, interact, create and communicate.

2. 8ist out the building blocs of multimedia.• $et• "mage• 3ound• Animation• 9ideo

&. How audio files are stored in 'A9 format($he 'A9 format is one of the simplest for string audio information. $he data is

stored in the raw with no preprocessing. $he 'A9 format is a Iicrosoft proprietary formatand is a special case of #esource "nterchange <ile <ormat.A 'A9 file contains three chuns of information.

• $he #"<< chun O identifies the file• $he <7#IA$ chun O identifies the parameters• $he DA$A chun contains the actual samples

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). Define the following respective to sound; 4i5 'aveform 4ii5 <re+uency 4iii5 Amplitudei) Waveorm

3ound is produced by the vibration of matter. During the vibration pressure variationare created in the air surrounding it. $he pattern of the oscillation is called a waveform.!ii) "requenc#

$he fre+uency of the sound is the reciprocal value of the period. "t represents thenumber of period s in a second and it is measured in Hertz 4Hz5 or cycles per second.!iii) Amplitude

A sound also has amplitude. $he amplitude of a sound is a measure of thedisplacement of the air pressure wave from its, or +uiescent state.

*. Define +uantization 4or5 resolution($he resolution 4or5 +uantization of a sample value depends on the number of bits used

in measuring the height of the waveform. An 0-bit +uantization yields 2* possible values,1-bit CD-+udra +uantization results in over **& values.

. 'hat are the types of sound ob6ects that can be used in multimedia production($here are four types of sound ob6ects that can be used in multimedia production;

• 'aveform audio• I"D" sound tracs• Compact disc 4CD5 audio• I!& files

/. 8ist out the input devices of multimedia."nput devices for a multimedia system are as follows;

•  Eeyboards•  Iouse•  $racball•  $ouch screen•  Iagnetic card %ncoders and #eaders•  Graphics $ablets•  3canners•  7ptical Character #ecognition 47C#5 devices•  9oice #ecognition 3ystems•  Digital cameras

0. 8ist out the components of I"D" interface.A I"D" interface has two different components;

• Hardware• Data format

$ard%are connects the e+uipment. "t specifies the physical connection betweenmusical instruments, stimulate that a port I"D" port is built into an instrument, specifies aI"D" cable and deals with electronic signals t that are sent over the cable.

Data ormat encodes the information traveling through the hardware I"D" dataformat includes an instrument Oconnected data format. $he encoding includes, besides theinstrument specification, the notion of the beginning and end of a note, basic fre+uency andsound volume> I"D" data allow an encoding of about 1 octaves, which corresponds to 120notes.

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. Define the following terms; 4i5 Compression #atio 4ii5 "mage Nuality &ompression 'atio:

$he Compression #atio represents the size of the original image divided by thesize of the compressed image.(mage ualit#:

Compression ratio typically affects picture +uality, the higher the compression ratio,the lower the +uality of the decompressed image.

1. 'hat are the basic tools that are re+uired for the multimedia 3oftware(• $et %diting ? 'ord !rocessing $ools• !ainting ? Drawing $ools• "mage O %diting $ools• 3ound %diting $ools• Animation, video ? Digital Iovie $ools

11. 'hat is I"D"( How audio files are converted to I"D"( I"D"4Iusical "nstrument Digital "nterface5 is an industry-standard protocol that

enables electronic musical instruments, computers and other e+uipment to communicate,control and synchronize with each other.

12. 8ist the challenges in multimedia.• 3torage organization and management.• A viable physical bandwidth in the delivery path to the users.• Nuality of service 4No35 management4real time delivery and adaptability

to the environment5• "nformation management4indeing and retrieval5• =ser satisfaction• 3ecurity4especially management of content rights5

1&. 'hat is called authoring tool(Iultimedia authoring tools provide the important framewor needed for organizing

and editing the elements of multimedia pro6ect including graphics sounds, animations andvideo clips.

Authoring tools used for designing interactive and the user interface for presenting the pro6ect on screen and for assembling elements into a single cohesive pro6ect*#pes :

• Card or page based tools• "con based, event O driven tools• $ime based and presentation tools• ob6ect oriented tools

1). Iention the various hypermedia document models• 3GI8 43tandard Generalized Iarup 8anguage5• 7DA 47pen Document Architecture5

1*. Define the term flicer in video.A periodic fluctuation of brightness perception is called flicer effect.

1. 'hat is audio streaming(  $he ability to play audio as it is being received as opposed to downloading an entireaudio file and launching an audio player is called audio streaming.

1/. 'hat #$!(#eal-time $ransport !rotocol 4#$!5 provides support for the transport of real-

 

time data such as video and audio streams.

10. 'hat is P!%G(Point !hotographic %perts Group 4P!%G5 or P!G files are a type of compressed

 bitmap file. $his lossy compression techni+ue reduces the size of an image by discardingdetails that are typically too insignificant for the human eye to detect.

1. 'rite applications of multimedia.Iultimedia finds its application in various areas including, but not limited to,

• Advertisements• Art• %ducation• %ntertainment• %ngineering• Iedicine• Iathematics• usiness• 3cientific #esearch• 3patial $emporal Applications

2. 'hat is rasterization(#asterization is the tas of taing an image described in a vector graphics format and

converting it into a raster image for output on a video display or printer, or for storage in a bitmap file format.

1. 'hat are the minimum re+uirements needed for running multimedia application($o develop a multimedia application good hardware and software support is needed.

Iost importantly developing a multimedia re+uires creative sills.$he minimum re+uirements are

$ard%are : "nput devices lie mouse, tracballSot%are : 7perating system, multimedia authoring tools

2. Different between database and multimedia databaseA conventional database system does contain tet and discrete data whereas

multimedia database system besides tet and decrete data, it contains audio and videoinformation. $he components of multimedia database include

• $et• "mages• Audio

&. How is sharing of applications performed in a centralized architecture and replicatedarchitecture(

"n the case of centralized architecture every process has to wait and share commonmemory. $hus applications are loaded and sharing is possible.

"n the case of replicated architecture copy of the application will be loaded in thelocal memory of each processor, so they need not wait for sharing.

). 'hat are the N73 parameters($he N73 parameters describe the speed and reliability of data transmission. $hey are

• $hroughput• $ransit delay• %rror rate• 3ynchronization

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*. Define synchronization3ynchronization is timeeeping which re+uires the coordination of events to operate a

system in unison. "n a multimedia presentation, synchronization ensures that the audio andvideo components are timed correctly. "n a computer to computer communications, thehardware and software must be synchronized to that the file transfers can tae place.

. 'hat is a session manager(3ession management architecture is built around an entity session manager, which

separates the control from the transport. y creating a reusable session manager, which isseparated from the user interface, conference oriented tools avoid a duplication of their effort.

/. 8ist the various functionalities of session manager 3ession manager includes local and remote functionalities. 8ocal functionalities include;

• Iembership control management• <loor control• Iedia control management• Configuration management• Conference control management

0. 'hy file format is necessary(<ile formats are necessary to;

• Define the storage of media data on diss• 3pecify synchronization• 3pecify timing• $o hold metadata

. 'hat is virtual reality(9irtual reality 49#5 is a technology which allows a user to interact with a computer-

simulated environment. $he user is presented with simulated environment which may be areal world or an imaginary world but appears and feels lie a real environment.

1. How virtual scenes are generated($wo methods are used for generating virtual scenes. $hey are

$he computer O generated scene is displayed through a load-mounted viewing system asa stereoscopic pro6ection

Display stereoscopic pro6ection on a sister monitor, with the two stereoscopic viewsdisplayed on a alternate refresh cycle.

11. 3tate the problems faced in the event-loop based programs method ofvirtual reality.

3imulation loops; 3ets of ob6ects participated in a simulation. A procedure iscreated, and a time step is allocated, for each ob6ect. $he simulation rate is bound to displayrate and each procedures is assigned a slot in the time line for the simulation. $his is called aloop because the main process loops around a simple logic of which ob6ect is scheduled net.Disadvantages: Controlling the duration of a procedure. %ample, A server may tae toolong.

12. 'hat are the higher levels of multimedia communication system 4IC35($he higher layers of the multimedia communication system are divided into two

architectural subsystems;• Application subsystem

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• $ransport subsystem.

1&. 8ist out the tools for collaborative computing$he tools used for collaborative computing are as follows;

• %lectronic mail• ulletin boards4e.g. =senet news5• 3creen sharing tools4e.g. show me from sunsoft5• $et-based conferencing systems 4e.g. "nternet relay chat,

Compu3erve,America online5• $elephone conference systems.• Conference rooms4e.g. video window from ellcore5• 9ideo conference systems4e.g.,Ibone tools5

1). 'hat is an I!C($he I!C computer is not a hardware unit but rather a standard that includes

minimum specifications to turn "ntel microprocessor-based computers into multimediacomputers.

1* . 8ist all the I!C standards$here are currently three I!C standards as follows

• I!C 8evel 1• I!C 8evel 2• I!C 8evel &

$he standards apply not only to destop computers but also to increasingly more powerfulmultimedia laptops.

1. 'hat is meant by streaming video($ransmission of real time video over the internet is called streaming video.

%ample Fewscasts, distance learning.

1/. 'hat is a 9ideo dis(9ideo dis serves as the output of motion pictures and audio. $he data are stored in an

analog-coded format on the dis. $he reproduced data meet the highest +uality re+uirements.9ideo dis has a diameter of approimately &cm and stores approimately 2. Giga bytes.

10. 'hat is interactive video(=se of a videodisc or CD-#7I that is controlled by a computer for an interactive

education or entertainment program.

1. 'hat is video conferencing(A videoconference 4also nown as a video teleconference5 is a set of interactive

telecommunication technologies which allow two or more locations to interact via two-wayvideo and audio transmissions simultaneously

2. 'rite short note on video on demand(9ideo on demand systems are systems which allow users to select and watch video

content over a networ as part of an interactive television system. 9ideo on demand is a greatway of viewing films and television programs. "t eliminates the need to go to video store to buy films and provides access to a wide collection of material.

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  Short questions !+ mar,s)

1. Give and eplain the action of at least four turbo CQCBB output primitives and outputof these output primitives.

2. Iae a short note on functional characteristics of various input device.&. Derive the resenham@s circle algorithm .Generate the intermediate points of a circle

whose centre is at 4, 5 and two given points on the circumference are 4, 15, and4R1,R15 i.e., intermediate points in the second +uadrant.

). <ind out the transformation matri which reflects points above the line, &B)y *.*. Derive a composite matri which maps a rectangular window into a rectangular view

 port using the basic geometric transformation in 2-D4i.e. using translation and scaling5. %plain the different algorithms used for region filling. 'hat steps are re+uired to be

added to a fill algorithm if a region is to be filled with a pattern(/. 'hy need of hidden-surface algorithms( How does the M-buffer algorithm determinewhich surface are hidden(0. !erform a )* degree rotation of triangle A4,5,41,15,C4*,25  4a5 About the origin 4b5 About the !4-1,-15. <ind the matri of mirror reflection with respect to the plane passing through the originand having a normal vector whose direction is F"BPBE 1. 'hat do you mean by a pro6ection( Classify its different types. 'hat are the perspective anomalies(11. 'hat do you understand by the interactive computer graphics( 'hat are the essentialcomponents of an interactive computer pacage(12. %plain rehsenham@s line drawing algorithm and use it to find all points on a linedrawn between 44,5 and 4&,05 in a raster scan display.1&. %plain viewing transformation and discuss the role of clipping in the applications ofthese transformations. Describe any one 2-D clipping algorithm for lines.1). 8ist and eplain functions of a Graphic pacage.1*. Fame various pointing and positioning devices. riefly eplain the woring of any 2devices.1. Draw and eplain the bloc diagram of typical worstation.1/. %plain the architecture of vector scan display.10. %plain the architecture of raster scan display.1. %plain the simple raster display system.2. %plain the raster display system with peripheral display.21. %plain the raster display system with integerated display processor.22. 'rite a short note on 9ideo Controller.2&. %plain the random scan display system.2). 'rite a short note on;  a5 Eeyboard  b5 Iouse  c5 $racball and spaceball  d5 Poystic 

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  e5 Digitizer   f5 8ight pens  g5 $ouch !anels  h5 3canner 2*. %plain the important characteristics of hard copy devices.2. Define dot size, addressability, "nterdot distance and resolution.2/. Give the characteristics of !rinters.20. %plain various types of printers.2. Give the differences between line printer and dot matri printer.&. 8ist the features of in-6et printer.&1. 'rite a short note on 8aser printer.&2. %plain the principle of thermal transfer printer.&&. 'rite a short note on pen plotter.

&). 'rite a short note on;  a. !erspective transformation

 b. %tend and bounding volumes  c. ac face cutting&*. %plain the M-uffer algorithm for hidden surface removal.&. %plain the advantages and disadvantages of M-uffer

Algorithm&/. %plain the depth sort algorithm for hidden surface removal.&0. %plain the binary space partition tree visible surface  Algorithm and write a pseudocode for building a 3! tree.&. %plain the scan line algorithm for hidden surface removal.). %plain any one area subdivision algorithm for visible surface  Detection.)1. 'rite a pseudocode for 'eiler-Atherton algorithm.)2. Give the important steps involved in 'eiler-Atherton  Algorithm visible surface algorithm.)&. %plain A-uffer visible surface algorithm.)). Describe floating horizon algorithm.)*. Describe the bac-face removal algorithm.

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MC9234 COMPUTER GRAPHICS QUESTION BANK

1. What is scan conversion?A major task of the display processor is digitizing a picture definitiongiven in an application program into a set of pixel-intensity values forstorage inthe frame buffer. his digitization process is called scan conversion.

!. Write the properties of video display devices?"roperties of video display devices are persistence# resolution# and aspectratio.

$. What is rasterization? he process of determining the appropriate pixels for representing pictureor graphics object is kno%n as rasterization.

&. 'efine (omputer graphics.(omputer graphics remains one of the most existing and rapidly gro%ingcomputer fields. (omputer graphics may be defined as a pictorialrepresentationor graphical representation of objects in a computer.

). *ame any four input devices.+our input devices are keyboard# mouse# image scanners# and trackball.

,. Write the t%o techniues for producing color displays %ith a (?/eam penetration method# shado% mask method

0. What is vertical retrace of the electron beam?n raster scan display# at the end of one frame# the electron beam returnsto theleft top corner of the screen to start the next frame# is called verticalretrace of theelectron beam.

2. Write a short notes on video controller.3ideo controller is used to control the operation of the display device. Afixedarea of the system is reserved for the frame buffer# and the videocontroller is

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given direct access to the frame buffer memory.

4. What is bitmap?5ome system has only one bit per pixel6 the frame buffer is often referredto asbitmap.

17. 'ifferentiate plasma panel display and thin film electro luminescentdisplay?n plasma panel display# the region bet%een t%o glass plates is filled %ithneon gas. n thin film electro luminescent display# the region bet%een t%oglasses plates are filled %ith phosphor# such as zinc sulphide doped %ithmanganese.

11. What is resolution? he maximum number of points that can be displayed %ithout overlap ona ( is referred to as the resolution.

1!. What is horizontal retrace of the electron beam?n raster scan display# the electron beam return to the left of the screenafterrefreshing each scan line# is called horizontal retrace of the electronbeam.

1$. What is filament?n the (# heat is applied to the cathode by directing a current through acoil of %ire# is called filament.

1&. What is pixmap?5ome system has multiple bits per pixel# the frame buffer is often referredto as pixmap.

1). Write the types of clipping?"oint clipping# line clipping# area clipping# text clipping and curveclipping.

1,. What is meant by scan code?When a key is pressed on the keyboard# the keyboard controller places acode carry to the key pressed into a part of the memory called as thekeyboardbuffer. his code is called as the scan code.

10. 8ist out the merits and demerits of "enetration techniues? he merits and demerits of the "enetration techniues are as follo%s

o  t is an inexpensive techniue

o  t has only four colors

o  he uality of the picture is not good %hen it is compared to other techniues

o  t can display color scans in monitors

o  "oor limitation etc.

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12. 8ist out the merits and demerits of '35? he merits and demerits of direct vie% storage tubes 9'35: are asfollo%s

o  t has a flat screen

o  efreshing of screen is not reuired

o  5elective or part erasing of screen is not possible

o  t has poor contrast

o "erformance is inferior to the refresh (.

14. What do you mean by emissive and non-emissive displays? he emissive display converts electrical energy into light energy. heplasmapanels# thin film electro-luminescent displays are the examples. he *on-emissive are optical effects to convert the sunlight or light fromanyother source to graphic form. 8iuid crystal display is an example.

!7. 8ist out the merits and demerits of "lasma panel display?;erits

o  efreshing is not reuired

o  "roduce a very steady image free of +licker

o  8ess bulky than a (.

'emerits

o  "oor resolution of up to ,7 d.p.i

o  t reuires complex addressing and %iring

o  t is costlier than (.

!1. What is persistence? he time it takes the emitted light from the screen to decay one tenth ofitsoriginal intensity is called as persistence.

!!. What is Aspect ratio? he ratio of vertical points to the horizontal points necessary to producelength of lines in both directions of the screen is called the Aspect ratio.<suallythe aspect ratio is =.

!$. What is the difference bet%een impact and non-impact printers?mpact printer press formed character faces against an inked ribbon on tothe paper. A line printer and dot-matrix printer are examples.*on-impact printer and plotters use 8aser techniues# inkjet sprays#>erographic process# electrostatic methods and electro thermal methodsto getimages onto the papers. xamples are@ nkjet8aser printers.

!&. 'efine pixel?"ixel is shortened forms of picture element. ach screen point is referredto aspixel or pel.

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!). What is frame buffer?"icture definition is stored in a memory area called frame buffer or refreshbuffer.

!,. Where the video controller is used?A special purpose processor# %hich is used to control the operation of thedisplay device# is kno%n as video controller or display controller.

!0. What is run length encoding?un length encoding is a compression techniue used to store theintensityvalues in the frame buffer# %hich stores each scan line as a set of integerpairs.Bne number each pair indicates an intensity value# and second numberspecifiesthe number of adjacent pixels on the scan line that are to have thatintensity value.

!2. What is point in the computer graphics system? he point is a most basic graphical element C is completely defined by apair of user coordinates Dx# yE.

!4. Write short notes on lines?

A line is of infinite extent can be defined by an angle of slope θ and onepoint on the line "F"Dx#yE. his can also be defined as yFmxG( %here ( isthe Hintercept.

$7. 'efine (ircle?(ircle is defined by its center xc# yc and its radius in user coordinate units. he euation of the circle is Dx-xcE G Dy-ycE F r!.

$1. What are the various attributes of a line? he line type# %idth and color are the attributes of the line. he line typeinclude solid line# dashed lines# and dotted lines.

$!. What is antialiasing? he process of adjusting intensities of the pixels along the line tominimize the effect of aliasing is called antialiasing.

$$. What is ransformation? ransformation is the process of introducing changes in the shape sizeandorientation of the object using scaling rotation reflection shearing Ctranslationetc.

$&. What is translation? ranslation is the process of changing the position of an object in astraight-line path from one coordinate location to another. very point Dx #yE inthe object must under go a displacement to Dx|#y|E. the transformation is@x| F x G tx 6 y| F yGty

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$). What is rotation?A !-' rotation is done by repositioning the coordinates along a circularpath# in the x-y plane by making an angle %ith the axes. hetransformation is

given by@ >| F r cos Dθ G φE and H| F r sin Dθ G φE.

$,. What is scaling?A !-' rotation is done by repositioning the coordinates along a circularpath# in the x-y plane by making an angle %ith the axes. he

transformation is given by@ >| F r cos Dθ G φE and H| F r sin Dθ G φE.

$0. What is shearing? he shearing transformation actually slants the object along the >direction or the H direction as reuired. ie6 this transformation slants theshape of an object along a reuired plane.

$2. What is reflection? he reflection is actually the transformation that produces a mirror imageof an object. +or this use some angles and lines of reflection.

$4. What are the t%o classifications of shear transformation?> shear# y shear.

&7. A point D&#$E is rotated counterclock%ise by an angle of &)°. +ind therotationmatrix and the resultant point.

&1. *ame any three font editing tools.esdit# +B*ographer#

&!. 'ifferentiate serif and sans serif fonts. Iive one example5erif fonts has a little decoration at the end of the letter# but serif font hasnot. imes# ne% century schoolbook is the examples of serif fonts. Arial#potimaare examples for sans serif fonts.

&$. 'istinguish bet%een %indo% port C vie% port?A portion of a picture that is to be displayed by a %indo% is kno%n as%indo% port. he display area of the part selected or the form in %hichtheselected part is vie%ed is kno%n as vie% port.

&&. 'efine clipping?(lipping is the method of cutting a graphics display to neatly fit apredefinedgraphics region or the vie% port

&). What is the need of homogeneous coordinates? o perform more than one transformation at a time# use homogeneous

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coordinates or matrixes. hey reduce un%anted calculations intermediatestepssaves time and memory and produce a seuence of transformations.

&,. 'istinguish bet%een uniform scaling and differential scaling?When the scaling factors sx and sy are assigned to the same value# auniformscaling is produced that maintains relative object proportions. <neualvalues forsx and sy result in a differential scaling that is often used in designapplication

&0. What is fixed point scaling? he location of a scaled object can be controlled by a position called thefixed point that is to remain unchanged after the scaling transformation.

&2. What is /ezier /asis +unction?/ezier /asis functions are a set of polynomials# %hich can be used insteadof the primitive polynomial basis# and have some useful properties forinteractivecurve design.

&4. What is surface pathA single surface element can be defined as the surface traced out as t%oparameters Du# vE take all possible values bet%een 7 and 1 in a t%o-parameterrepresentation. 5uch a single surface element is kno%n as a surfacepatch.

)7. 'efine /-5pline curve?A /-5pline curve is a set of piece%iseDusually cubicE polynomial segmentsthatpass close to a set of control points. Jo%ever the curve does not passthrough these control points# it only passes close to them.

)1. What is a spline? o produce a smooth curve through a designed set of points# a flexiblestrip called spline is used. 5uch a spline curve can be mathematicallydescribed %ith a piece%ise cubic polynomial function %hose first andsecond derivatives are continuous across various curve section.

)!. What are the different %ays of specifying spline curve?

o  <sing a set of boundary conditions that are imposed on the spline.

o  <sing the state matrix that characteristics the spline

o  <sing a set of blending functions that calculate the positions along

the  curve path by specifying combination of geometric constraints onthe curve

)$. What are the important properties of /ezier (urve?

o  t needs only four control points

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o  t al%ays passes through the first and last control points

o   he curve lies entirely %ithin the convex half formed by four

controlpoints.

)&. 'efine "rojection? he process of displaying $' into a !' display unit is kno%n asprojection. he projection transforms $' objects into a !' projectionplane.

)). What are the steps involved in $' transformation?o ;odeling ransformationo 3ie%ing ransformation

o "rojection ransformation

o Workstation ransformation

),. What do you mean by vie% plane?A vie% plane is nothing but the film plane in camera %hich is positionedand oriented for a particular shot of the scene.

)0. 'efine projection? he process of converting the description of objects from %orldcoordinates to vie%ing coordinates is kno%n as projection.

)2. What you mean by parallel projection?"arallel projection is one in %hich z coordinates is discarded and parallellines from each vertex on the object are extended until they intersect thevie% plane.

)4. What do you mean by "erspective projection?"erspective projection is one in %hich the lines of projection are notparallel. nstead# they all converge at a single point called the center ofprojection.

,7. What is "rojection reference point?n "erspective projection# the lines of projection are not parallel. nstead#they all converge at a single point called "rojection reference point.

,1. 'efine computer graphics animation?(omputer graphics animation is the use of computer graphics euipment%here the graphics output presentation dynamically changes in real time. his is often also called real time animation.

,!. What is t%eening?t is the process# %hich is applicable to animation objects defined by aseuence of points# and that change shape from frame to frame.

,$. 'efine frame?Bne of the shape photographs that a film or video is made of is kno%n asframe.

,&. What is key frame?

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Bne of the shape photographs that a film or video is made of the shape ofan object is kno%n initially and for a small no of other frames called keyframe.

,). 'efine ;ultimedia;ultimedia is the use of the computer to present and combine text#graphics# audio and video %ith links and tools that lets the user tonavigate# interact# create and communicate.

,,. What is multimedia "(@A multimedia "( is a computer that has a ('-B; or '3' drive andsupports 2-bit and 1,-bit %aveform audio recording and playback# ;'soundsynthesis# and ;"I movie %atching# %ith a central processor fastenough and a A; large enough to enable the user to play and interact%ith these media in realtime# and %ith a hard disk large enough to storemultimedia %orks that the user can create.

,0. Where to use multimedia?;ultimedia improves information relation. ;ultimedia applicationsincludes the follo%ing@

o /usinesso 5chools

o Jome

o "ublic place

,2. 8ist out the benefits of multimedia/enefits of multimedia are

o  raining

o 5ales

o (ommunicationso ;edicines

,4. What is hypermedia?A set of documents in %hich a given document can contain text# graphicsvideo and audio clips as %ell as embedded references to other documents%orld %ide %eb pages are hypermedia documents.

07. What is hypertext?Jyper text is an application of indexing text to provide a rapid search ofspecific text strings in one or more documents. Jypertext is an integralpart of hypermedia documents. n multimedia applications# a hypermediadocuments is the basic complex object of %hich text is a sub-object. Bthersub-objects in the basic object include images# sound# and full-motionvideo.

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