DipIETE – CS (OLD SCHEME)

 

 

Code: DC09                                                                            Subject: COMPUTER GRAPHICS

Flowchart: Alternate Process: DECEMBER 2009Time: 3 Hours                                                                                                     Max. Marks: 100

 

 

NOTE: There are 9 Questions in all.

·      Question 1 is compulsory and carries 20 marks. Answer to Q. 1 must be written in the space provided for it in the answer book supplied and nowhere else.

·      Out of the remaining EIGHT Questions answer any FIVE Questions. Each question carries 16 marks.

·      Any required data not explicitly given, may be suitably assumed and stated.

 

 

Q.1       Choose the correct or the best alternative in the following:                                (2  10)

       

a.       The homogenous co-ordinates (hx, hy, h) represents a point

 

                   (A)  (x, y, h)                                        (B)  (x, y)

(C)    (hx, hy)                                       (D)  (x, y, 1)

       

b.      A device which allows displayed objects or screen positions to be selected with touch of a finger is

 

(A)    Touch Panel                                 (B)  Image Scanner

(C)  Digitizer                                        (D)  Joystick

            

             c.   Fluorescence is the term used to describe the light given off by a phosphor ________ it has been exposed to an electron beam.

                  

(A)    before                                          (B) is being

(C)  after                                             (D) None

 

             d.   Which of the following is a technique for image data compression?

 

(A)    PHIGS                                       (B)  Cell-encoding

(C)  Run-length decoding                    (D)  Run-length encoding   

 

             e.   The composite transformation matrix to perform a rotation of 45° about a fixed point (x,y) is

                                                                                               

(A)     T –1(x, y)  R45°  T(x, y)                        (B)  T(x, y)  R45°  T –1(x, y)

(C)  T(x, y)  R(–45°)  T –1(x, y)                     (D)  T –1(x, y)  R(–45°)  T(x, y)

 

             f.    Which of the following is used for rendering objects?

                  

(A)     Bresenham’s algorithm                 (B)  OCTREE

(C)  Hidden Surface algorithm              (D)  None

 

            


 

 

             g.   The specular-reflection parameter ns for dull surfaces is assigned a value near

 

(A)     1                                                  (B) 10

(C)  100                                              (D) Infinite

 

             h.   For a self similar fractal constructed with different scaling factors for the different parts e.g. sk for part k then

                  

                   D is fractal dimension of the fractal, the value of m is

 

(A)    <1                                                (B) >1

(C) –1                                                 (D) +1

 

             i.    The Mandelbrot set is an example of

 

(A)   Self-squaring fractals                     (B)  self-inverse fractals

(C)  self-affine-fractals                         (D)  None

 

             j.    Two illuminated phosphor spots are distinguishable when their seperation is greater than the diameter at which the spot intensity has fallen to _______ percent of the maximum.

 

(A)  50                                                (B)   60

(C)  40                                                (D)   30

 

 

Answer any FIVE Questions out of EIGHT Questions.

Each question carries 16 marks.

 

  Q.2     a.   Discuss shadow masks technique for coloured CRT.                                          (6)

       

             b.   Give three applications of computer graphics.                                                     (5)

 

             c.   Describe briefly the architecture of raster graphics system with display processor.               (5)

 

  Q.3     a.   What are the two types of touch panels? Describe the working of touch panels.                  (8)

       

             b.   Using DDA algorithm give the position of first four pixels for the line joining the points (x1, y1) and (x2, y2).                                                           (8)

 

  Q.4     a.   Describe briefly zooming and panning.                                                                (4)

 

             b.   Write the steps of Bresenham Circle drawing algorithm.                                      (8)

 

             c.   If p0, p1, p2, ... pn are (n+1) control points of a Bezier Curve then show that        (4)

                  

 

       

 

Q.5       a.   Give the steps for drawing a Bezier Curve by hand with four control points. Hence draw the Bezier curve with control points p0(30, 0), p1(0, 0), p2(0, 50), p3(100, 100), p4(100, 0), p5(30, 0).         (8)

            

             b.   Give the definition and knot vectors for the uniform cubic B-spline, open uniform B-spline.              (4)

 

             c.   Write the cox-deBoor recursion formula for B-splines.                                        (4)

 

  Q.6     a.   Use Cohen-Sutherland algorithm to clip a line joining points (60, 300) and (860, 700) in the rectangular window with end points (120, 200),

                   (540, 200), (120, 1500) & (540, 1500).                                                            (5)

 

             b.   Describe Scan Line Seed fill algorithm for polygon filling.                                    (8)

 

             c.   Describe Solid modeling using sweep operation.                                                 (3)

 

  Q.7     a.   What do you mean by perspective projection? What are the three main perspective projection types?                                                                    (4)   

 

             b.   Scale the triangle with vertices A(0,0), B(1,1) and C(5,2) to three times its size while keeping C(5,2) fixed.                                                            (6)

 

             c.   Describe briefly z-Buffer algorithm for detecting visible surfaces.                         (6)

       

  Q.8     a.   Describe a shading model for a source of light having three colour components red, green and blue.                                                                       (8)

 

             b.   Explain briefly hypermedia.                                                                                 (3)

 

             c.   What do you mean by multimedia? What are the essential components of Multimedia system?                                                                    (5)

       

  Q.9     a.   Describe the video conferencing as an application of multimedia.                         (8)

 

             b.   What are the advantages of MIDI over digital audio?                                          (8)