Code: T-14                                Subject: IMAGE PROCESSING & COMPUTER GRAPHICS

Time: 3 Hours                                                      June 2006                                                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 best alternative in the following:                                         (2x10)

a. Emissive and nonemissive displays are categories of  

(A)  Light emitting diode displays         (B)  Flat panel displays

(C)   Gas discharge displays                 (D)  Liquid crystal displays

b. The aspect ratio of a 12in  16in display is

(A)  2:1                                               (B)  4:3

(C)  1:2                                               (D)  3:4

             c.   The transformation matrix that defines scaling simultaneously a units in the X direction and b units in the Y direction is given by

(A) (B)

(C) (D)

             d.   Efficient method for obtaining rotation about a specified axis is

(A) Polar representation                     (B)  Quaternion representation

(C) Binary representation                    (D)  Cartesian representation

             e.   This projection is used by drafters and engineers to create working drawings of an object.

(A) Parallel                                          (B)  Perspective

(C) Oblique                                         (D)  Perpendicular

             f.    When no a priori model of the degradation model is available, the quality of an image is improved by

(A) Image compression                        (B) Image restoration

(C) Image normalization                       (D) Image enhancement

             g.   If the components of the image histogram are concentrated on the low side of the gray scale, then the image is a

(A) High contrast image                       (B)  Low contrast image

(C)  Dark image                                  (D)  Bright image

             h.   Color video camera uses this color model

(A) RGB                                            (B) HSI

(C) CMYK                                         (D) CMY

             i.    Which is used to detect the presence of an edge at a point in an image?

(A) Sign of first derivative                   (B) Magnitude of first derivative.

(C) Magnitude of second derivative.     (D) Sign of second derivative.

             j.    Image compression techniques that reduce only coding redundancy are

(A)  Transform coding techniques         (B)  Lossy compression techniques

(C)  Region splitting and Merging.        (D) Lossless compression techniques

Answer any FIVE Questions out of EIGHT Questions.

Each question carries 16 marks.

Q.2     a.   Write short notes on the following:

(i)   Mouse                                          (ii)  Scanners

                   (iii) Touch panels                                                                                               (9)

             b.   Compare and contrast raster scan and random scan display systems with necessary block diagrams.                                                                      (7)

Q.3     a.   Explain the steps involved in Bresenhem line algorithm with an example.              (8)

             b.   Explain the Liang Barsky line clipping algorithm with necessary equations.           (8)

Q.4     a.   Show that two successive reflections about either of the coordinate axes is equivalent to a single rotation about the coordinate origin.                  (8)

b.   Illustrate with the help of diagrams the effect of the shearing transformations on the square A(0, 0), B(1, 0), C(1, 1) and D(0, 1) with (i)  x direction shearing parameter 2  (ii)  y direction shearing parameter 3 and (iii)  both together.                                                                                                    (8)

Q.5     a.   What are visible surface detection algorithms?  Explain the steps of a depth buffer algorithm with necessary figures.                                                (8)

     b.   A unit cube is projected onto the xy plane.  Draw the projected image using the standard perspective transformation with respect to (i) d = 1 and  (ii)  d = 10, where d is the distance from the view plane.                                                           (8)

  Q.6     a. What is the necessity of a color model?  Explain the following color models with necessary equations and applications (i)  RGB  (ii)  CMY & CMYK.                                                                      (8)

             b.   A common measure of transmission for digital data is the baud rate, defined as the number of bits transmitted per second.  Transmission is accomplished in packets consisting of a start bit, a byte of information, and a stop bit.  How many minutes would it take to transmit a 1024 1024 image with 256 gray levels using a 56K baud modem?  What would the time at 750K baud, a representative speed of a phone DSL connection?                                         (8)

Q.7     a.   Consider the following figure where each small rectangle represents a pixel and the value inside it is gray level at that pixel.  For the highlighted center, find the output of a mean filter, median filter, max filter, min filter (all of window size 3  3) and the weighted average filter given by                           (8)

0	1	0	6	7
2	0	1	6	5
1	1	7	5	6
1	0	6	6	5
2	5	6	7	6

. The given figure is

b.   Explain the image filtering technique in frequency domain with a block diagram.  Compare and contrast the following filters in frequency domain with relevant diagrams.  (i)  Unsharp masking  (ii)  High boost. (8)

Q.8     a.   Find the Huffman codes for the following symbols.                                              (8)

Symbol	Probability
A	0.07
B	0.05
C	0.13
D	0.008
E	0.48
F	0.022
G	0.06
H	0.18

             b.   Explain the following coding techniques with examples (i)  LZW coding   (ii)  Bit plane coding.                                                                   (8)

Q.9     a.   Mention the basic formulation of region segmentation.  Explain the region splitting and merging technique for image segmentation with an example.    (8)

b.   Explain the following spatial filters with the corresponding masks            (i) Sharpening filters (ii) Smoothing filters.                                                  (4x2 =8)