## Computer-Graphics

 Question 1
Give the number of principal vanishing point(s) along with their direction for the standard perspective transformation:
 A Only one in the direction K B Two in the directions I and J C Three in the directions I, J and K D Only two in the directions J and K
Question 1 Explanation:
There is only one principal vanishing point and it is in K-direction.
 Question 2
 A (a)-(i), (b)-(ii), (c)-(iii), (d)-(iv), (e)-(v) B (a)-(ii), (b)-(iii), (c)-(i), (d)-(iv), (e)-(v) C (a)-(iii), (b)-(i), (c)-(ii), (d)-(v), (e)-(iv) D (a)-(iv), (b)-(v), (c)-(i), (d)-(ii), (e)-(iii)
Question 2 Explanation:
Flood Gun: An electron gun designed to flood the entire screen with electrons.
Collector: Partly energized by flooding gun stores the charge generated by the writing gun.
Ground: Used to discharge the collector.
 Question 3
Which of the following is not a component of Memory tube display ?
 A Flooding gun B Collector C Ground D Liquid Crystal
Question 3 Explanation:
Memory tube display components:
1. Connector Pins
2. Electron Gun
3. Base
4. Focusing System
5. Control Grid Voltage
6. X/Y Deflect
7. Phosphor
8. Collector
9. Ground
Note: Liquid crystal is not a component of memory tube display
.
 Question 4
Which of the following is not true in case of Oblique Projections?
 A Parallel projection rays are not perpendicular to the viewing plane. B Parallel lines in space appear parallel on the final projected image. C Used exclusively for pictorial purposes rather than formal working drawings. D Projectors are always perpendicular to the plane of projection.
 Question 5
With respect to CRT, the horizontal retrace is defined as:
 A The path an electron beam takes when returning to the left side of the CRT. B The path an electron beam takes when returning to the right side of the CRT. C The technique of turning the electron beam off while retracing. D The technique of turning the electron beam on/off while retracing.
 Question 6
A 4*4 DFT matrix is given by :

Where values of x and y are _____, _____ respectively.
 A 1, −1 B −1, 1 C −j, j D j, −j
 Question 7
If we want to resize a 1024 × 768 pixels image to one that is 640 pixels wide with the same aspect ratio, what would be the height of the resized image?
 A 420 Pixels B 460 Pixels C 480 Pixels D 540 Pixels
Question 7 Explanation:
Aspect Ratio= Width / Height
Aspect ration of 1024 × 768 pixels image = 1024/768
= 4/3
Aspect ration of modified pixels image = 640/height
4/3 = 640/height
Height = (3*640)/4
Height = 480 Pixels
 Question 8
Consider the following statement with respect to approaches to fill area on raster systems:
(P) To determine the overlap intervals for scan lines that cross the area.
(Q) To start from a given interior position and paint outward from this point until we encounter the specified boundary conditions.
Select the correct answer from the options given below:
 A P only B Q only C Both P and Q D Neither P nor Q
Question 8 Explanation:
Fill area on raster systems:
TRUE: To determine the overlap intervals for scan lines that cross the area.
TRUE: To start from a given interior position and paint outward from this point until we encounter the specified boundary conditions.
 Question 9
This transformation is called
 A Scaling B Shear C Homography D Steganography
 Question 10
Given below are different properties of 3D projections from A.D. Identify the correct order on the basis of property true of (i) a perspective projection only (ii) an orthographic projection only (iii) both orthographic and projective transformations and (iv) neither orthographic nor projective transformation, respectively. (A) Straight lines are mapped to straight lines. (B) Distance and angles are (in general) preserved. (C) Far away objects appear the same size as closer ones. (D) Requires homogeneous coordinates in order for it to be encoded into linear transformation. Choose the correct answer from the options given below:
 A D, C, B, A B B, C, D, A C D, C, A, B D C, D, B, A
 Question 11
Match List-I with List-II. List-I gives 33 matrices representing 2D transformations and List-II shows the corresponding transformation diagrams.

Choose the correct answer from the options given below:
 A A-IV, B-II, C-III, D-I B A-IV, B-III, C-II, D-I C A-III, B-II, C-IV, D-I D A-II, B-IV, C-III, D-I
 Question 12
Given below are two statements: Statement I: Bezier curves are curves that interpolate all of their control points Statement II: A cubic bezier curve has four control points. In the light of the above statements, choose the correct answer from the options given below
 A Both statement I and Statement II are true B Both Statement I and Statement II are false C Statement I is correct but Statement II is false D Statement I is incorrect but Statement II is true
 Question 13
Concerning phong shading and gouraud shading in a 3D scene, which of the following statements are true? (A) Gouraud shading requires more computation than phong shading (B) Gouraud shading linearly interpolates the color of an interior pixel from the color at the vertices. (C) Phong shading interpolates over the normal vectors specified at the vertices. Choose the correct answer from the options given below:
 A (A) and (B) only B (A) and (C) only C (B) and (C) only D (A), (B) and (C)
 Question 14
n the context of 3D Computer graphics, which of the following statements is/are correct? A) Under perspective projection, each set of parallel lines in the object do not stay parallel in the image (except those that are parallel to the view plane to start with). B) Applying a perspective transformation in the graphics pipeline to a vertex involves dividing by its ‘z’ coordinate. C) Perspective transformation is a linear transformation. Choose the correct answer from the options given below:
 A (A) and (B) only B (A) and (C) only C (B) and (C) only D (A), (B) and (C)
 Question 15
Consider the following statements:
a) 3D Studio Max includes a number of high-level professional tools for character animation, game development, and visual effect production.
b) MAYA is a complete modeling package developed by Microsoft
c) RenderMan is a rendering package developed by Pixar
Which of the above statements are true?
 A Only a and b B Only a and c C Only b and c D a,b and c
Question 15 Explanation:
MAYA 3D animation software offers a comprehensive creative feature set for 3D computer animation, modeling, simulation, rendering, and compositing on a highly extensible production platform. Maya has next-generation display technology, accelerated modeling workflows, and tools for handling complex data.
 Question 16
The ____ file format allows storing an animation sequence
 A PNG B GIF C JPG D PDF
Question 16 Explanation:
→PDF means portable document format.
→Portable Network Graphics is a raster-graphics file-format that supports lossless data compression.
→JPG/JPEG: Joint Photographic Experts Group. JPEG is usually known as JPG. It stands for Joint Photographic Expert Group, a joint working group of International Standardization Organization (ISO) and International Electrotechnical Commission (IEC). It is a standard method of compressing graphic images.
→A GIF is a computer file that is used on the internet for sending images, especially moving images. GIF is an abbreviation for 'Graphic Interchange Format'.
 Question 17
Memory mapped displays
 A are utilized for high resolution graphics such as maps B uses ordinary memory to store the display data in character form C stores the display data as individual bits D are associated with electromechanical teleprinters
Question 17 Explanation:
● Graphs can be displayed on a screen by writing character values into a special area of RAM within the video controller. ● Prior to cheap RAM that enabled bit-mapped displays, this character cell method was a popular technique for computer video displays.
 Question 18

Which of the following statements is/are True regarding the solution to the visibility problem in 3D graphics ?

S1 : The Painter’s algorithm sorts polygons by depth and then paints (scan - converts) each Polygon onto the screen starting with the most nearest polygon. S2 : Backface Culling refers to eliminating geometry with back facing normals. Code :
 A S1 only B S2 only C Both S1 and S2 D Neither S1 Nor S2
Question 18 Explanation:
Visibility problem in 3D graphics
1. Painter's algorithm
- A depth sorting method
- Surfaces are sorted in the order of decreasing depth
- Surfaces are drawn in the sorted order, and overwrite the pixels in the frame buffer - Subtle difference from depth buffer approach: entire face drawn
- Two problems:
• It can be nontrivial to sort the surfaces
• There can be no solution for the sorting order
2. Back Face Culling
- Back faces: faces of opaque object which are “pointing away” from viewer
- Back face culling – remove back faces (supported by OpenGL)
How to detect back faces
- If we find backface, do not draw, save rendering resources
- There must be other forward face(s) closer to eye
- F is face of object we want to test if backface
- P is a point on F
- Form view vector, V as (eye – P)
- N is normal to face F
3. View-Frustum Culling
- Remove objects that are outside the viewing frustum
- Done by 3D clipping algorithm (e.g. Liang-Barsky)
4. Ray Tracing
- Ray tracing is another example of image space method
- Ray tracing: Cast a ray from eye through each pixel to the world
5. Z(Depth buffer algorithm)
Reference: https://web.cs.wpi.edu/~emmanuel/courses/cs543/slides/lecture08_p2.pdf
 Question 19
A frame buffer array is addressed in row major order for a monitor with pixel locations starting from (0,0) and ending with (100,100). What is address of the pixel(6,10)? Assume one bit storage per pixel and starting pixel location is at 0.
 A 1016 B 1006 C 610 D 616
Question 19 Explanation:
Given data,
Pixel location starts from =(0,0)
Pixel location ends from =(100,100)
Hint: Frame buffer array is addressed in row major order
. Step-1: Row major order is= 0+1((6-0)+101(10-0))
= 0+6+1010
= 1016
 Question 20
 A A B B C C D D
 Question 21
Transformation that moves objects without deformation is called:
 A Rotation B Scaling C Translation D Morphism
Question 21 Explanation:
→ A translation process moves every point a constant distance in a specified direction. It can be described as a rigid motion.
→ A translation can also be interpreted as the addition of a constant vector to every point, or as shifting the origin of the coordinate system.
 Question 22
Using Mid Point algorithm, the new coordinates of the point P(x,y) having slope ‘m’ and constant and ‘b’ is calculated using:
 A F(x,y)=mx+b-y B F(x,y)=mx-y+b C F(x,y)=mx+b D F(x,y)=mx-y+b-y
Question 22 Explanation:
In order to check this, we need to consider the implicit equation:
F(x,y) = mx + b - y
For positive m at any given X,
If y is on the line, then F(x, y) = 0
If y is above the line, then F(x, y) < 0
If y is below the line, then F(x, y) > 0
 Question 23
The process of rotating the image by 1800 without changing its size is called:
 A Translation B Rotation C Scaling D Reflection
Question 23 Explanation:
The process of rotating the image by 1800 without changing its size is called Rotation
 Question 24
Anti aliasing is important to improve readability of text. It deals with the
 A Elimination of "jaggies" B Spacing between two individual characters C Underlining letters D Spacing of a group of characters
Question 24 Explanation:
● Antialiasing removes jagged edges by adding subtle color changes around the lines, tricking the human eye into thinking that the lines are not jagged.
● The slight changes in color around the edges of an image help the line blend around curves, giving the impression that the line is true.
● These color changes are made on a very small scale that the human eye cannot detect under normal circumstances. In order to be able to see that an image has been antialiased, it would have to be magnified.
 Question 25
What is the bitrate for transmitting uncompressed 800x600 pixel color frame with 8 bits/pixel at 40 frames/Second?
 A 1536 Mbps B 2.4 Mbps C 15.36 Mbps D 153.6 Mbps
Question 25 Explanation:
Step-1: Given data, Uncompressed pixel = 800*600
Step-2: Each of 8 bit = 800*600 *8
Step-3: Bit rate for transmitting = 800*600 *8 *40 =153600000 bits
Step-4: Here, they are given in Mbps. 153600000 bits =153.6Mbps
 Question 26
The easiest method in flash to draw a heptagon, is to use the___
 A Polystar tool with the "Polygon" style B Polygon Tool C Lasso Tool with the "create star" option D Polystar Tool with the "star" style
Question 26 Explanation:
There are 3 tools for drawing geometric shapes
1. Rectangle(Rectangle tool)
2. Oval(Oval tool)
3. Polygon(Polystar tool)
Note: We are not using Option A,C and D for drawing heptagon.
 Question 27
___ is a special effect in motion pictures and animations that changes one image or sharp into another through a seamless transition
 A Tweening B Inverse kinematics C Morphing D Tweaking
Question 27 Explanation:
Morphing is a special effect in motion pictures and animations that changes (or morphs) one image or shape into another through a seamless transition. morphing means stretching or as part of a fantasy or surreal sequence. Traditionally such a depiction would be achieved through cross-fading techniques on film.
 Question 28
Given that a 22 inch monitor with an aspect ratio of 16:9 has a monitor of 1920x1080, what is the width of the monitor?
 A 22 inches B 8:53 inches C 10:79 inches D 19:17 inches
Question 28 Explanation:

Step-1: To check the ratio [width/height= 1920 /1080 ]
Step-2: Ratio: 16/9.
Step-3: Using Pythagoras theorem (9x)​ 2​ +(16x)​ 2​ =(22)​ 2
x=19.17 inch
 Question 29
Even when the screen is completely dark while the film is in motion, commercial motion pictures use
 A 32 frames per second or 101 screen illuminations per second B 72 frames per second or 234 screen illuminations per second C 8 frames per second or 32 screen illuminations per second D 24 frames per second or 72 screen illuminations per second
Question 29 Explanation:
→ Motion picture, also called film or movie, series of still photographs on film, projected in rapid succession onto a screen by means of light.
→ When a motion picture film is projected on a screen at the rate of at least 16 illuminations per second but the commercial motion pictures uses 24 frames per second or 72 screen illuminations per second.
→ Film Technology standard is 24 frames per second, a three bladed shutter and some dreamy motion blur, all projected as shadow and light on the side of a wall.
 Question 30
The file size of a 640 by 480 pictures of 256 colours in a 8-bit resolution is
 A 300KB B 900KB C 128KB D 1024KB
Question 30 Explanation:
●Give picture size with 640 by 480 resolution with 256 colors per pixel.
●This implies 640 * 480 = 307,200 pixels. Recall that 256 values requires 8 bits of computer storage.
●Hence (307,200 pixels) * (8 bits per pixel) = 2,457,600 bits of storage.
●A common method for selling computer storage is in 8 bit groupings called bytes.
●Hence the picture would require (2,457,600 bits) / (8 bits per byte) = 307,200 bytes of computer storage.
 Question 31
The process of producing bitmapped images from a view of 3-D models in a 3-D scene is called
 A Rendering B Looping C Cross dissolving D Imaging
Question 31 Explanation:
Rendering or image synthesis is the automatic process of generating a photorealistic or non-photorealistic image from a 2D or 3D model (or models in what collectively could be called a scene file) by means of computer programs.
 Question 32
Which of the following is interactive?
 A A radio broadcast B A talk show on TV C A newspaper D A computer game
Question 32 Explanation:
Options A,B and C are not interactive , it will provide only information to the people. Where as Computer game in which computer user should interact with the computer in order to play the game
 Question 33
While making bubbled lists, which of the following options are available?
 A Square,disc,tringle B Triangle,disc,circle C Triangle,square,circle D Disc,square,circle
Question 33 Explanation:
→ Disc: A filled circle
→ Circle : An unfilled circle
→ square : A filled square
 Question 34
MPEG involves both spatial compression and temporal compression. The spatial compression is similar to JPEG and temporal compression removes_____frames.
 A Voice B Spatial C Temporal D Redundant
Question 34 Explanation:
MPEG: The MPEG codec can only be used when the final video file will be in MPEG format (it is not compatible with other file types). It uses a lossy compression scheme (although it may be lossless at high-quality settings) and spatial and temporal compression. MPEG offers the best compression possible, but MPEGs are not yet as widely supported on the Web as other video formats.
Spatial compression:
Spatial (or intraframe) compression takes place on each individual frame of the video, compressing the pixel information as though it were a still image. JPEG, PNG and PICT files are an example of spatial compression.
It is known as the intraframe method.

Temporal compression:
It happens over a series of frames of the video. Temporal (or interframe) compression happens over a series of frames and takes advantage of areas of the image that remain unchanged from frame to frame, throwing out data for repeated pixels.
It is also called the interframe method.
 Question 35
In which of the following, the density of the core remains constant from the center to the edges?
 A Single mode fiber B Multimedia step-index fiber C Multimode graded index fiber D Single mode step index fiber
Question 35 Explanation:
Multimode Step-index: In multimode step-index fiber, the density of the core remains constant from the center to the edges. A beam of light moves through this constant density in a straight line until it reaches the interface of the core and the cladding
 Question 36
Which of the following is a special effect in motion pictures and animation that changes one image/picture into another through a seamless transition?
 A Modeling B Morphing C Animating D Wrapping
Question 36 Explanation:
→ Morphing is a special effect in motion pictures and animations that changes (or morphs) one image or shape into another through a seamless transition.
→ Morphing means stretching or as part of a fantasy or surreal sequence.
 Question 37
Which of the following compression algorithms is used to generate a .png file?
 A LZ78 B Deflate C LZW D Huffman
Question 37 Explanation:
→ Deflate is a lossless data compression algorithm and associated file format that uses a combination of the LZ77 algorithm and Huffman coding.
→ An algorithm producing Deflate files is widely thought to be implementable in a manner not covered by patents.
→ This has led to its widespread use, for example in gzip compressed files, PNG image files and the ZIP file format for which Katz originally designed it.
 Question 38
Which of the following is not an image type used in MPEG?
 A A frame B B frame C D frame D P frame
Question 38 Explanation:
A Group Of Pictures can contain the following picture types:
I picture (or) I frame (intra coded picture) – a picture that is coded independently of all other pictures. Each GOP begins (in decoding order) with this type of picture.
P picture (or) P frame (predictive coded picture) – contains motion-compensated difference information relative to previously decoded pictures. Each P picture can only reference one picture, and that picture must precede the P picture in display order as well as in decoding order and must be an I or P picture.
B picture (or) B frame (bi predictive coded picture) – contains motion-compensated difference information relative to previously decoded pictures. Each B picture can only reference two pictures, the one which precedes the B picture in display order and the one which follows, and all referenced pictures must be I or P pictures.
D picture or D frame (DC direct coded picture) – serves as a fast-access representation of a picture for loss robustness or fast-forward. D pictures are only used in MPEG-1 video.
 Question 39
Perform window to viewport transformation for the point (20, 15). Assume that (Xwmin, Ywmin) is (0,0); (Xwmax, Ywmax) is (100,100); (Xvmin, Yvmin) is (5,5); (Xvmax, Yvmax) is (20,20). The value of x and y in the viewport is
 A x = 4 , y = 4 B x = 3 , y = 3 C x = 8 , y = 7.25 D x = 3 , y = 4
Question 39 Explanation:

 Question 40
Using the phong reflectance model, the strength of the specular highlight is determined by the angle between
 A The view vector and the normal vector B The light vector and the normal vector C The light vector and the reflected vector D the reflected vector and the view vector
Question 40 Explanation:
Specular highlights on objects appear, because the light reflected from the object hits viewer. Sometimes, we are hit directly by the light and the highlight appears to be very intense, and sometimes we are hit so slightly, that we basically don't see the specular highlight. The strength of this highlight depends on the cosine of the angle between the reflected vector and vector taken from the point at object to the viewer's position:

 Question 41

Beam-penetration and shadow-mask are the two basic techniques for producing color displays with a CRT. Which of the following is not true ?

I. The beam-penetration is used with random scan monitors.

 A I and II B II and III C III only D IV only
Question 41 Explanation:
Beam Penetration Method for displaying color pictures has been used with random-scan monitors. Two layers of phosphor, usually red and green, are coated on to the inside of the CRT screen, and the displayed color depends on how far the electron beam penetrates into the phosphor layers.
Shadow-mask Methods are commonly used in raster-scan systems (including color TV) because they produce a much wider range of color than the beam penetration method. A shadow-mask CRT has three phosphor color dots at each pixel position. One phosphor dot emits a red light, another emits a green light, and the third emits a blue light.
 Question 42
Line caps are used for adjusting the shape of the line ends to give them a better appearance. Various kinds of line caps used are
 A Butt cap and sharp cap B Butt cap and round cap C Butt cap, sharp cap and round cap D Butt cap, round cap and projecting square cap
Question 42 Explanation:
Line caps helps in improving the appearance of the line by adjusting the shape of line ends There are three types of line caps:
1. But Cap 2. Round Cap 3. Projection Square Cap
 Question 43

Given below are certain output primitives and their associated attributes. Match each primitive with its corresponding attributes :

List – I List – II

a. Line i. Type, Size, Color

b. Fill Area ii. Color, Size, Font

c. Text iii. Style, Color, Pattern

d. Marker iv. Type, Width, Color
 A a-i, b-ii, c-iii, d-iv B a-ii, b-i, c-iii, d-iv C a-iv, b-iii, c-ii, d-i D a-iii, b-i, c-iv, d-ii
Question 43 Explanation:
Line Attributes: Basic attributes of a straight line segment are its type, its width, and its color. In some graphics packages, lines can also be displayed using selected pen or brush options.
AREA-FILL ATTRIBUTES: Basic attributes of an area-fill are
Fill Styles: Areas are displayed with three basic fill styles: hollow with a color border, filled with a solid color, or Wed with a specified pattern or design.
Pattern Fill
Soft Fill: the linear soft-fill algorithm repaints an area that was originally painted by merging a foreground color F with a single background color 8, where F + B.The current RGB color P of each pixel within the area to be refilled is some linear combination of F and B:
P = tF + (1- t)B
where the "transparency" factor t has a value between 0 and 1 for each pixel. RGB component of the colors
P = (PR, PC, PR), F = (FR, Fc, FR), B = (BR, Bc, BB)
Text Attributes: Following are the text attributes:
Font : is the choice of font (or typeface), which is a set of characters with a particular design style such as New York, Courier, Helvetica, London, 'Times Roman, and various special symbol groups.
Font size
Font colour
Marker Attributes: A marker symbol is a single character that can be displayed in different colors and in different sizes. We select a particular character to be the marker symbol with
setMarkerType (int)
Hence Marker attributes are type, size and color.
 Question 44
Consider a window bounded by the lines : x = 0; y= 0; x = 5 and y = 3. The line segment joining (–1, 0) and (4, 5), if clipped against this window will connect the points
 A (0, 1) and (2, 3) B (0, 1) and (3, 3) C (0, 1) and (4, 3) D (0, 1) and (3, 2)
Question 44 Explanation:
 Question 45
Which of the following color models are defined with three primary colors ?
 A RGB and HSV color models B CMY and HSV color models C HSV and HLS color models D RGB and CMY color models
Question 45 Explanation:
Common color models defined with three primary colors are the RGB and CMY models.
RGB: color scheme is an additive model. Intensities of the primary colors are added to produce other colors. Each color point within the bounds of the cube can be represented as a triple (R, G, B), where values for R, G, and B are assigned in the range from 0 to 1. Thus, a color C, is expressed in RGB components as
C = RR + GG + BB
CMY: A color model defined with the primary colors cyan, magenta, and yellow (CMY) is useful for describing color output to hard-copy devices. We can express the conversion from an RGB representation to a CMY representation with the matrix transformation:
 Question 46
A technique used to approximate halftones without reducing spatial resolution is known as _________.
 A Halftoning B Dithering C Error diffusion D None of the above
 Question 47

In Cyrus-Beck algorithm for line clipping the value of t parameter is computed by the relation :

(Here P1 and P2 are the two end points of the line, f is a point on the boundary, n1 is inner normal)
 A (P1 – fi) × ni / (P2 – P1) × ni B (fi – P1) × ni / (P2 – P1) × ni C (P2 – fi) × ni / (P1 – P2) × ni D (fi – P2) × ni / (P1 – P2) × ni
 Question 48
 A a-i, b-iii, c-iv, d-ii B a-ii, b-iii, c-i, d-iv C a-iv, b-ii, c-iii, d-i D a-i, b-ii, c-iii, d-iv
Question 48 Explanation:
Cavalier Projection: The direction of projection is chosen so that there is no foreshortening of lines perpendicular to the xy plane.
Cabinet Projection: The direction of projection is chosen so that lines perpendicular to the xy planes are foreshortened by half their lengths.
Isometric Projection: The direction of projection makes equal angles with all of the principal axis.
Orthographic Projection: Projections are characterized by the fact that the direction of projection is perpendicular to the view plane.
 Question 49
Which of the following graphic primitives are considered as the basic building blocks of computer graphics ?
(a)Points
(b)Lines
(c)Polylines
(d)Polygons
 A (a) only B (a) and (b) C (a), (b) and (c) D (a), (b), (c) and (d)
Question 49 Explanation:
Ponits, lines and polygon lines are the basic building blocks of computer graphics
 Question 50
Which of the following is/are the principal components of a memory-tube display ?
(a)Flooding gun
(b)Collector
(c)Phosphorus grains
(d)Ground
 A (a) and (b) B (c) only C (d) only D All the above
Question 50 Explanation:

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