Soved Questions of Previous Years

Q1: What is computer graphics? Explain different applications of computer graphic in several fields?

( year - 2016,2017,2018 ,2019,2022 )

Computer graphics is an art of drawing pictures on computer screens with the help of programming. It involves computations, creation, and manipulation of data.

In other words, we can say that computer graphics is a rendering tool for the generation and manipulation of images.

Computer Art:
Using computer graphics we can create fine and commercial art which include animation packages, paint packages

Computer Aided Drawing:
Designing of buildings, automobile, aircraft is done with the help of computer aided drawing,

Presentation Graphics:
For the preparation of reports or summarising the financial, statistical, mathematical, scientific, economic data for research reports, managerial reports,

Entertainment:
Computer graphics finds a major part of its utility in the movie industry and game industry.

Education:
Computer generated models are extremely useful for teaching huge number of concepts and fundamentals in an easy to understand and learn manner.

Training:
Specialised system for training like simulators can be used for training the candidates in a way that can be grasped in a short span of time with better understanding.

Q2: What is difference between Raster image and Vector image?

( year-2016 )

Q3: What is clipping Name different types of clipping?

( year-2016,2017 )

Clipping is the process of drawing pixels only to a selected region or well-defined window.

Types of Clipping:

1. Point Clipping
2. Line Clipping
3. Area Clipping (Polygon)
4. Curve Clipping
5. Text Clipping
6. Exterior Clipping

Q4: What is Bezier curve? write two characterstics of bezier curve?

( year-2016,2017 )

A bezier curve is particularly a kind of spline generated from a set of control points by forming a set of polynomial functions. Discovered by the french engineer Pierre bezier.

Bezier curves have the following properties −

• They generally follow the shape of the control polygon, which consists of the segments joining the control points.
• They always pass through the first and last control points.
• They are contained in the convex hull of their defining control points.
• A Bezier curve generally follows the shape of the defining polygon.
• No straight line intersects a Bezier curve more times than it intersects its control polygon.They are invariant under an affine transformation.

Q5:What is animation ? Name different types of animation?

( year-2016,2017,2022 )

Computer animation is a visual digital display technology that processes the moving images on screen.

The key/main concept behind computer animation is to play the defined images at a faster rate to fool the viewer so that the viewer should interpret those images as a continuous motion of images.

Different types of animation

Traditional animation (also known as cel animation) is hand drawn.

2D Animation is the art of creating movement by combining a sequence of images together in a two-dimensional space.

3D Animation is the art of bringing digital characters, vehicles, props, and full scenes to life in a virtual 3D space.

Motion capture helps enhance the realism of 3D animations. It's used in movies like Avatar and Lord of the Rings and video games like LA Noire and Grand Theft Auto.

Motion graphics animation is how you animate text logos and basic illustrations

Q 6 : What is Frame Buffer Memory?

Year - (2017)

An area of memory used to store information related to the pixels of a display.

The frame buffer is the size of the maximum image that can be displayed

Q 7 : Explain the good characterstics of line.

Year - (2017)

1. Line should appear Straight
2. Lines should terminate accurately
3. Lines should have constant density
4. Line density should be independent of line length and angle

Q 8 : What is GUI? Explain.

Year - (2017)

A graphical user interface (GUI) is an interface through which a user interacts with electronic devices such as computers and smartphones through the use of icons, menus and other visual indicators or representations (graphics).

Q 9 : Define Sheer transformation.

Year - (2018)

A transformation that slants the shape of an object is called the shear transformation

Q 10 : What is refresh rate ?

Year - (2018)

• Refresh rate can be defined as the number of times the screen is refreshed per second.
• It’s SI unit or unit of measurement is Hertz(Hz).
• A display appears stable if the refresh rate is high enough, but if the refresh rate is too low, the display will flicker, causing eye strain and headaches.

Q 11 : What is pixel and Frame Buffer?

Year - (2019)

Pixels are the smallest unit in a digital display. Up to millions of pixels make up an image or video on a device's screen.

A frame buffer is a large, contiguous piece of computer memory. At a minimum there is one memory bit for each pixel in the rater; this amount of memory is called a bit plane. The picture is built up in the frame buffer one bit at a time.

Q 12 : What is Flicking ?

Year - (2019)

A flicker is the appearance of flashing or unsteadiness in an image on a display screen. This issue can occur when the video refresh rate is too low

Q 13 : What is the draw back of DDA line generation algorithm and advantage of Bresenham's line algorithm

(Year- 2022 )

Drawback of DDA:

1. It involves floating point additions rounding off is done. Accumulations of round off error cause accumulation of error.
2. Rounding off operations and floating point operations consumes a lot of time.
3. It is more suitable for generating line using the software. But it is less suited for hardware implementation.

Advantage of Breshenam's algorithm:

1. It involves only integer arithmetic, so it is simple.

2. It avoids the generation of duplicate points.

3. It can be implemented using hardware because it does not use multiplication and division.

4. It is faster as compared to DDA (Digital Differential Analyzer) because it does not involve floating point calculations like DDA Algorithm.

Q 14: What is viewing transformation ? What is difference between window and view port ?

(Year- 2022 )

Window to Viewport Transformation is the process of transforming 2D world-coordinate objects to device coordinates. Objects inside the world or clipping window are mapped to the viewport which is the area on the screen where world coordinates are mapped to be displayed.

Window –It is the area on the world coordinate selected for display.

ViewPort –It is the area on the device coordinate where graphics is to be displayed.

Q 15 : What is Digital video ? Explain the use of digital video in developing multimedia applications.

(Year- 2022 )

Digital video is audio/visual content in a binary format, with information is presented as a sequence of digital data rather than in a continuous signal as analog information is.

Q 16 : What are the animation file formats? List the animation software's.

(Year- 2022 )

Animation file formats:

• SVG - animated SVG with SMIL or CSS.
• APNG - Animated PNG file format
• GIF - Graphics Interchange Format

Section -B

Q 1: What is transformation? Explain the basic 2D transformation with example?

(Year- 2016 )

2D Transformation in computer graphics is a process of modifying and re-positioning the existing graphics in 2 dimensions. .

Scaling

A scaling transformation alters size of an object. In the scaling process, we either compress or expand the dimension of the object. Scaling operation can be achieved by multiplying each vertex coordinate (x, y) of the polygon by scaling factor sx and sy to produce the transformed coordinates as (x’, y’). So, x’ = x * sx and y’ = y * sy.

The scaling factor SX, SY scales the object in X and Y direction respectively. The above equations can also be represented in matrix form as below −

Translation

A translation process moves every point a constant distance in a specified direction.

To translate a point from coordinate position (x, y) to another (x1 y1), we add algebraically the translation distances Tx and Ty to original coordinate.

Rotation:

It is a process of changing the angle of the object. Rotation can be clockwise or anticlockwise.

Q 2: for 10 x 10 frame buffer interpret the breshenham algorithm to find which pixel turned on for the line segment (1,2) and (7,6)?

(Year- 2016 )

Q 3:Explain the sutherland-hodgeman clipping algorithm for polygon clipping and also implement it by considering example?

(Year- 2016,2017 )

It is performed by processing the boundary of polygon against each window corner or edge. First of all entire polygon is clipped against one edge, then resulting polygon is considered, then the polygon is considered against the second edge, so on for all four edges.

Q 4 : What is clipping? Explain the mid point sub-division algorithm.

(Year- 2017 )

Clipping is the process of drawing pixels only to a selected region or well-defined window.

It is used for clipping line. The line is divided in two parts. Mid points of line is obtained by dividing it in two short segments.

Again division is done, by finding midpoint. This process is continued until line of visible and invisible category is obtained. Let (xi,yi) are midpoint.

Q 5 : Explain three basic rule of animation with example.

(Year- 2017,2019 )

1. Squash and Strech

This describes the importance and understanding of the weight and volume of drawing any object or character.

2. Anticipation

This is the situation where the animator will try to create some scenes, and the audience will wait for something happening, but nothing will happen.

3. Staging

Staging should be perfect in any animation. Staging means the animator should create such types of scenes and characters that the audience is attracted to these scenes. This makes a complete animation more interesting, and the audience does not lose their interest.

4. Straight Ahead

This principle describes that all the scenes should be drawn first from the beginning to the ending, the animator should fill the interval scene.

5. Flow Through and Overlapping Action

This principle describes about the different speeds of two or more objects in the same scene.

6. Slow In and Slow Out

This principle describes those characters and objects whose more importance is in the between scenes, and they are slow or negligible in the beginning and ending.

Q 6 : Scale the square ABCD [ A(0,0), B(3,0) C(3,3) & D(0,3) ], three units in y-direction with respect to origin

(Year- 2017)

Q 7 : Describe most commonly colour models used in computer graphic.

( Year -2018 )

RGB Color Space:

RGB stands for Red, Green, and Blue. This color space is widely used in computer graphics. RGB are the main colors from which many colors can be made.

CMYK Color Model:

CMYK stands for Cyan, Magenta, Yellow and Black. CMYK color model is used in electrostatic and ink-jet plotters which deposits the pigmentation on paper

HSV Color Model:

HSV stands for Hue, Saturation, and Value (brightness). It is a hexcone subset of the cylindrical coordinate system. The human eye can see 128 different hues, 130 different saturations and number values between 16 (blue) and 23 (yellow).

HLS Color Model:

HLS stands for Hue Light Saturation. It is a double hexcone subset. The maximum saturation of hue is S= 1 and L= 0.5. It is conceptually easy for people who want to view white as a point.

Q 8 : Describe any method for visible surface detection.

Year -2018 )

The process of identifying what surfaces and parts of surfaces can be seen from a particular viewing angle.

Scan-Line Method:

It is an image-space method to identify visible surface. This method has a depth information for only single scan-line. In order to require one scan-line of depth values, we must group and process all polygons intersecting a given scan-line at the same time before processing the next scan-line. Two important tables, edge table and polygon table, are maintained for this.

The Edge Table − It contains coordinate endpoints of each line in the scene, the inverse slope of each line, and pointers into the polygon table to connect edges to surfaces.

The Polygon Table − It contains the plane coefficients, surface material properties, other surface data, and may be pointers to the edge table.

To facilitate the search for surfaces crossing a given scan-line, an active list of edges is formed. The active list stores only those edges that cross the scan-line in order of increasing x. Also a flag is set for each surface to indicate whether a position along a scan-line is either inside or outside the surface.

Pixel positions across each scan-line are processed from left to right. At the left intersection with a surface, the surface flag is turned on and at the right, the flag is turned off. You only need to perform depth calculations when multiple surfaces have their flags turned on at a certain scan-line position.

Q 9 : What is bit plane? How bit plane is use to get different colours ?

Year -2018 )

(1) The sequence of bits for each pixel in a bitmap. The number of bits in the bit plane determines the number of colors that are displayed in the image. See bitmap and color depth.

(2) A segment of memory used to control an object, such as a color, cursor or sprite. Bit planes may be reserved parts of a common memory or independent memory banks each designed for one purpose.

Q 10 : explain raster and random scan display system

(year 2019)

Raster scan and random scan are two of the most popular approaches used to display the pictures and images of objects on the screen. Raster scan is a technique in which a rectangular pattern of the image is captured on screen, whereas random scan is one in which the picture is constructed through an electron beam.

Q 11 : It is desired to draw a line starting at A (3,6) and ending at B(6,2) on a graphics monitor use generalized Bresenham's algorithm to determine the pixels that world be put ON

(year -2022)

Q 12 : Show that this is same as coordination of matrix of 45 degree
clockwise rotation followed by reflection about x-axis and finally by counter clockwise rotations by 45 degree about origin (year-2022)

(year -2022)

Q 13 : Explain multimedia with suitable example? state the importance of animation in multimedia

(year -2022)

Multimedia is a representation of information in an attractive and interactive manner with the use of a combination of text, audio, video, graphics and animation.

In other words we can say that Multimedia is a computerized method of presenting information combining textual data, audio, visuals (video), graphics and animations. For examples: E-Mail, Yahoo Messenger, Video Conferencing, and Multimedia Message Service (MMS).

Importance of animation in multimedia

• Animation helps deepen visual understanding better than traditional diagrams.
• Animation omits unnecessary verbiage and visuals.
• It allows you to communicate ideas quickly and sharply.
• Animation is a cost-saving communication strategy.
• It educates & engages the audience through entertainment.
• It also provides real to life scenarios faced in daily life during learning, and so many other activities.

Section - C

Q 1 :What is CRT ? Explain the functioning of CRT with proper diagram?

(Year-2016)

CRT stands for Cathode Ray Tube. CRT is a technology used in traditional computer monitors and televisions. The image on CRT display is created by firing electrons from the back of the tube of phosphorus located towards the front of the screen.

Once the electron heats the phosphorus, they light up, and they are projected on a screen. The color you view on the screen is produced by a blend of red, blue and green light.

read functioning of crt

Q 2 : Write the steps to rotate an object about an arbitary point(h,k).Explain each step with proper diagram.

(Year-2016)

Rotation about an arbitrary point: If we want to rotate an object or point about an arbitrary point, first of all, we translate the point about which we want to rotate to the origin.

Then rotate point or object about the origin, and at the end, we again translate it to the original place. We get rotation about an arbitrary point.

example of rotation an arbitray point

Q 3 : What is Cubic Bezier Curve ? a cubic bezier curve is defined over the control points (1,1) (2,3) (4,4) and (6,1) calculate the parametric midpoints of this curve and show that its gradient dy/dx is 1/7 ?

(Year-2016)

Q 4 : What is Multimedia ? Explain the different categories of multimedia. also the different application of multimedia .

( Year-2016,2017,2018,2019)

Multimedia is a representation of information in an attractive and interactive manner with the use of a combination of text, audio, video, graphics and animation.

Categories of Multimedia

Linear Multimedia:

It is also called Non-interactive multimedia. In the case of linear multimedia, the end-user cannot control the content of the application. It has literally no interactivity of any kind. Some multimedia projects like movies in which material is thrown in a linear fashion from beginning to end.

Non-Linear multimedia

In Non-Linear multimedia, the end-user is allowed the navigational control to rove through multimedia content at his own desire. The user can control the access of the application. Non-linear offers user interactivity to control the movement of data. For example computer games, websites, self-paced computer-based training packages, etc.

Applications of Multimedia

• Education
• Entertainment
• Business
• Technology & Science
• Fine Arts
• Engineering

Q 5 : Explain the different 3-D animation software.also explain the different hardware required of computer animation.

(Year-2016)

(already done)

Q 6 : What is the use of animation? also explain different types of animation, and also explain the different applications of multimedia?

(Year -2017 )

(already done)

Q 7 : Explain the following terms-translation? Scaling & rotation about origin & reflection about x-axis

(Year -2017 )

Rotation

This type of transformation has an object about a fixed point without changing its size or shape.

Translation

This type of translation is defined as moving the object in space by keeping its size, shape or orientation constant. 

In a translation, each point of the shape must be moved in the same direction and for the same distance. When you are doing a translation, the primary object is called the pre-image, and the object after the translation is called the image.

scaling

scaling is a process of modifying or altering the size of objects. Scaling may be used to increase or reduce the size of the object.

Reflection:

It is a transformation which produces a mirror image of an object. The mirror image can be either about x-axis or y-axis. The object is rotated by180°.

Reflection about x-axis: The object can be reflected about x-axis with the help of the following matrix

In this transformation value of x will remain same whereas the value of y will become negative. Following figures shows the reflection of the object axis. The object will lie another side of the x-axis.

Read full topic about reflection

Q 8 : What do you mean by projection ? Differentiate between parallel and perspective projection.

(Year -2017 )

Representing an n-dimensional object into an n-1 dimension is known as projection. It is process of converting a 3D object into 2D object.

Parallel projections

Parallel projections are used by architects and engineers for creating working drawing of the object, for complete representations require two or more views of an object using different planes.

Perspective Projection :
Perspective projections are used by artist for drawing three-dimensional scenes.

Read in details from here

Q 9 : Perform a 45 degree rotation of triangle ABCD when A(0,0) ,B(1,1), and C (5,2) about origin

(Year -2017 )

Q 10 : what is polygon? also explain the polygon clipping.and define the sutherland hodegeman algorithm of polygon clipping.

(Year -2017 )

Polygon is nothing but a closed figure(end to end connected) made up of more than 2 line segments on a 2-dimensional plane

Polygon clipping is defined as the process of removing those parts of a polygon that lie outside a clipping window.

sutherland hodegaman algorigithm read here

Q 11 : Generate an origin centered circle with radius-2 with eight unique points on the circle.

(Year-2018 )

Q 12 : Rotate a triangle [ (4,6), (2,4), (6,2),] about the vertex (4,6) by 180 degree clockwise and find the new vetices.

(Year-2018 )

Q 13 : Differentiate between the terms multimedia system and multimedia application, with example.

(Year-2018 )

A multimedia system is responsible for developing a multimedia application. A multimedia application is a bundle of different kinds of data.

A multimedia computer system is one that can create, integrate, store, retrieve delete two or more types of media materials in digital form, such as audio, image, video, and text information.

Q 14 : A triangle ABC is A(0,0) , B(4,0) and C(0,4) Find the shearing transformation with a = 2 and b = 3 .

(Year-2018 )

Q 14 : Write Short notes on any three of the following:

(a) Projection

(b) Colour frame buffer

(c) 2 - buffer method

(d) DDA

(Year-2018 )

(already Done)

Q 15: Write down and explain the mid-point circle drawing algorithm. Assume 10 cm as the radius and co-ordinate origin as the centre of the circle.

(Year-2019 )

read here

Q 37 : What is basic concept of line drawing ? Explain Bresenham's line Algorithm to draw a line between any two end-points.

(Year-2019 )

The Line Drawing Algorithm is a graphical algorithm for representing line segments on discrete graphical media, such as printers and pixel-based media

A line drawing algorithm is a method for estimating a line segment on discrete graphical media such as pixel-based screens and printers in computer graphics.

(Already explained bresenham's algorithm)

Q 38 : Find 3 x 3 homogenous transformation matrix to transform square ABCD into another square A'B'C'D . side of original square =2 , coordinate of point A (20,10) Draw a final transformation graph paper,

(Year-2019 )

Q 39 : Define and Compare the Bezier curve and B-spline Curve.

(Year-2019 )

1. Spline :
A spline curve is a mathematical representation for which it is easy to build an interface that will allow a user to design and control the shape of complex curves and surfaces.

2. B-Spline :
B-Spline is a basis function that contains a set of control points. The B-Spline curves are specified by Bernstein basis function that has limited flexibility.

3. Bezier :
These curves are specified with boundary conditions, with a characterizing matrix or with blending function. A Bezier curve section can be filled by any number of control points. The number of control points to be approximated and their relative position determine the degree of Bezier polynomial.

Read difference here

Q 40 : Write short note on

(a) CRT

(b) Cohen-sutherland line clipping algorithm

(c) Window and View Port

(d) Polygon

(Year-2019 )

(Already done)

Q 47 : Define popular video recording formats and discuss their strength and weakness for use in multimedia with its benefits .

(Year-2022 )

MP4 video format:

MP4 has long been one of the most popular video file formats used on the web. It offers an excellent compromise between compression and video quality. The main codecs used with MP4 are H.264 and H.265.

Advantages

MP4 allows a good level of compression without compromising on image quality. One of its main advantages is that it allows you to easily combine several audio tracks and other elements in a single format.

Disadvantages

The high level of compression applied by the standard codecs makes MP4 files difficult to edit and produce.

AVI video format:

AVI stands for Audio Video Interleave. In other words, it is a format that combines audio and video. The format is widely used, but from a technical point of view, it is now somewhat outdated.

Advantages

The key advantage of this video format is that it is very widely accepted. There are barely any browsers or video players that don’t support AVI files.

Disadvantages

The technical limitations of this file format, and above all the lack of options for working with multiple audio tracks, mean that fewer and fewer users are turning to AVI.

MKV video format:

MKV is currently one of the most popular video file formats on the web. It is a powerful container format that can hold audio tracks, menus, and many other functions in addition to video files.

Advantages

Users choose MKV for its high-quality video files and its vast range of applications. It’s true that MKV format is only compatible with one codec, but this is freely available online.

Disadvantages

The main drawback of this file format is that the level of compression is low, meaning you can’t create very small files.

MOV video format

The MOV video format was developed by Apple and was originally intended for use with QuickTime. However, it has long been surpassed by alternative video formats and is no longer used much online.

Advantages

The format has the advantage of being easy to implement in Apple environments and allowing for the creation of very small files thanks to a high degree of compression.

Disadvantages

On the other hand, the powerful compression is also a disadvantage, because it results in loss of data and image quality. In other words, although you can create relatively small, compact files, the end result is usually disappointing.

OGG video format

One of the reasons that the OGG video file format was developed was to bring more flexibility to a market that was largely dominated by rights holders. OGG was, therefore, one of the first formats that could be used in the popular Linux environment, and quickly became well established on the market.

Advantages

The advantage of OGG lies in the fact that it is patent-free, widely accepted and is supported natively by the majority of browsers. This means that this format is a sensible choice if you want to add a video to your own website.

Disadvantages

Despite its wide distribution, the OGG video format does have some disadvantages. Both Safari and Internet Explorer only partially support it for example, so your video may not be displayed properly in these browsers.

VOB video format

VOB established itself early on as a standard for DVDs and is therefore mainly used for this type of media. It isn’t suitable for online use due to a lack of licenses and its low level of compression.

Advantages

The format can be read by any DVD player and offers a low level of compression. It can also contain multiple audio tracks.

Disadvantages

This format isn’t suitable for use online because you can’t upload VOB files to the various hosting platforms or to your own website. Also, a special codec is required to play videos in this format, and it isn’t freely available.

WMV video format

The WMV format was developed by Microsoft and is still widely used today. Because this format supports Digital Rights Management (DRM), it is generally used for video files that need to be copy protected.

Advantages

The format is reliably handled by all of the Microsoft operating systems.

Disadvantages

Since it is an older format, there is only partial support for very large video files. There are also limitations on file size and video quality.

Q 48 : Explain MIDI versus DIgital audio and also write the advantages and disadvantages of MIDI over digital audio.

(Year-2022 )

Digital Audio

Binary data is used to represent sound in digital audio. It entails transforming analog sound waves into a digital version that can be stored, handled and transferred using digital technology.

MIDI

Using a common set of commands and messages, the MIDI (Musical Instrument Digital Interface) protocol enables electronic musical instruments, computers, and other devices to communicate with one another. Instead of recording actual sound,

it is a method of encoding musical notes and performance data as digital information

Read full article here

Q 49 : Write down and explain the midpoint circle drawing algorithm. Assume 10 cm as the radius and co-ordinate origin as the center of circle.

(Year-2022 )

(Already explained midpoint circle drawing)

Q 50 : (i) Discuss the various input techniques in detail.

(Year-2022 )

(ii) Show a transformation matrix for rotating an object about a specified pivot point

solution link