AMIETE – IT (OLD SCHEME)

 

Code: AT14                               Subject: IMAGE PROCESSING & COMPUTER GRAPHICS

Flowchart: Alternate Process: JUNE 2010Time: 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:                                  (210)

       

             a.  This physical interactive device has a fixed location with a fixed origin.

 

                  (A) Joystick                                          (B) Mouse

                  (C) Trackball                                        (D) Spaceball

 

             b.  The time available for each scan line is_____________for a frame repetition rate of 30 fps and 525 lines in a frame.

 

                  (A) 63.5 ms                                          (B) 63.5 ns

                  (C) 53.5 ms                                          (D) 53.5 ns

 

             c.  The point (7, 3) changes to point___________after reflecting first about        y = 0 and then reflecting about x = 0.

 

(A) (7, 3)                                             (B) (–7, –3)

                  (C) (3, 7)                                             (D) (–3, –7)

 

d.    This projection is formed by parallel projectors from a center of projection at infinity that intersect the plane of projection at an oblique angle.

 

(A) Orthographic                                 (B) Axonometric

(C) Oblique                                         (D) Isometric

 

             e.  This algorithm is applicable to any object for which depth and shading characteristics can be calculated.

.

                  (A)  z-buffer                                         (B) Cohen-Sutherland

                  (C)  Midpoint circle                              (D) DDA

 

             f.   Sensor strips mounted in a ___________ configuration are used in medical and industrial imaging.

 

                  (A) line                                                 (B) ring

                  (C) single                                              (D) array

 

             g.  _______________ produce a double response at step changes in gray level.

 

            (A) Median filtering                               (B)  Averaging

                  (C) Second order derivatives                (D) First order derivatives

 

             h.  The frequency response of this filter is a constant function with a hole at the origin.

 

                  (A) notch                                              (B) lowpass

                  (C) highpass                                         (D) bandpass

 

             i.   If each codeword in a string of code symbols can be decoded without referencing succeeding symbols, then that code is called __________ code.

 

                  (A) uniquely decodable                         (B) block

                  (C) prefix                                             (D) instantaneous

 

             j.   This mask corresponds to ____________ mask.

 

                  (A) Line detection                                 (B) Gradient

                  (C) Laplacian                                       (D) Robert’s

 

 

Answer any FIVE Questions out of EIGHT Questions.

Each question carries 16 marks.

 

 

  Q.2     a.   In a raster scan graphics device, if pixels are accessed individually with an average access time of 200 nanoseconds, find the time required to access all the pixels in a 10241024 frame buffer. Calculate the refresh rate. Find the average access time required to achieve a refresh rate of 30 frames /second.               (8)

 

             b.   Explain the Z-buffer algorithm for creating 3D illusion on 2D screen.                    (8)

 

  Q.3     a.   Describe properties of a circle and derive the midpoint circle algorithm.               (8)

 

             b.   Suppose the center of an object is at [4 3] and it is desired to rotate the object by 90º counter clockwise about its center. Using homogeneous coordinates, explain the steps required to perform this and derive the combined transformation matrix for this transformation.                                       (8)

 

  Q.4     a.   Prove that the multiplication of three-dimensional transformation matrices for any two successive translations is commutative.                                    (8)

 

             b.   Describe the Cohen Sutherland line clipping algorithm.                                        (8)

 

  Q.5     a.   Explain the following projections: (i) Parallel projection (ii) Perspective projection.              (8)

 

             b.   Derive a composite three-dimensional transformation matrix for scaling with respect to a fixed point (x, y, z).                                                           (8)                                                             

 

  Q.6     a.   What is zooming of digital images? Explain nearest neighbor interpolation, pixel replication and bilinear interpolation. Compare performances of these interpolation techniques.                               (8)

 

            

 

             b.   A common measure of transmission for digital data is the baud rate, defined as 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 10241024 image with 256 gray levels using a 56 K baud modem? What would be the required time at 750 K baud?                                        (8)

 

  Q.7     a.   Explain the following filters in spatial domain. (i) Smoothing filters (ii) Gradient operators                 (8)

 

b.      An example 1010 gray scale image with a gray scale range of 16 is given below. Perform histogram equalization on this image and plot the histogram before and after processing.      (8)

 

                                   

 

  Q.8     a.   Given the alphabet A = {a, b, c, d, e} with frequency of occurrence        {20, 15, 5, 15, 45}, design a Huffman Code. Calculate the entropy of the alphabet and the average length of the code.    (8)

 

             b.   Explain transform coding with a block diagram. Describe zonal and threshold coding used in coding the transform coefficients.                          (8)

 

                                                                                                                                                                                                                                                                                                                 

  Q.9     a.   Explain the following: (i) Laplacian in frequency domain (ii) Laplacian of Gaussian.              (8)

 

             b.   Explain the global edge linking algorithm via the Hough transform.                       (8)