## Image Processing - May 2015

### Information Technology (Semester 7)

TOTAL MARKS: 80

TOTAL TIME: 3 HOURS
(1) Question 1 is compulsory.

(2) Attempt any **three** from the remaining questions.

(3) Assume data if required.

(4) Figures to the right indicate full marks.

** 1 (b) ** Extreme contrast straching is thresholding. (5 marks)

** 1 (c) ** Explain discrete time systems with example. (5 marks)

** 1 (d) ** Differentiate between spatial resolution & tonal resolution. (5 marks)

** 2 (a) ** x(t) = sin (480 πt) + 3sin(720 πt) is sampled with F_{s}=600 times per second.

i) What are the frequencies in radians in the resulting DT signal x[n]?

ii) If x[n] is passed through an ideal interpolator, what is the reconstructed signal. (10 marks)

** 2 (b) ** Perform following operations on given signal.

x(n)={1, 2, 3, 5}

i) x(-n -1)

ii) x(n-2)

iii) x(n+1)

iv) x(-n +2)

v) 2x(n). (10 marks)

** 3 (a) ** Obtain four directional chain code & shape representation of following image.
(5 marks)

** 3 (b) ** "Classify the signal as energy or power signal $$ x(n) = \left\{\begin{matrix}
\left ( \frac {1}{2} \right )^n & n \ge 0 \\ (2)
^n & n \le 0
\end{matrix}\right. $$" (5 marks)

** 3 (c) ** "Consider the image given below. Calculate direction of edge at the centre point of image. $$ I = \begin{bmatrix}
50 &80 &70 \\5
&50 &90 \\7
&9 &50
\end{bmatrix} $$" (10 marks)

** 4 (a) ** "For the following binary image perform morphological operation opening followed by closing. $$ A= \begin{matrix}
1 &0 &1 &0 &1 &0 &1 \\1
&1 &0 &1 &1 &0 &1 \\1
&1 &1 &1 & 1 &1 &1 \\1
&1 &1 &1 & 1&0 &0 \\1
&1 &0 &1 &1 &1 &1
\end{matrix} \ \ B = [(1) \ 1$$" (10 marks)

** 4 (b) ** Derive Fast Walsh Transform Flowgraph for N=4. (10 marks)

** 5 (a) ** If x[n]={1, 2, 3, 4} & h{n} = {1, 7}

Find linear convolution using circular convolution. (10 marks)

** 5 (b) ** Compare lossless and lossy comparison techniques. (5 marks)

** 5 (c) ** Object detecting using correlation principle. (5 marks)

### Write short notes on any two:

** 6 (a) ** Digital watermarking with application. (5 marks)

** 6 (b) ** Sampling & quantizations. (5 marks)

** 6 (c) ** Explain various frequency domain law pass filters in detail. (5 marks)

** 7 (a) ** Perform histogram stretching 50 that the new image has a dynamic range of [0, 7].

Gray level | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |

No. of pixel | 80 | 90 | 75 | 100 | 0 | 0 | 0 | 0 |

** 7 (b) ** State & prove any four properties of DFT. (10 marks)
**1 (a)** Prove that Highpass: Original - Lowpass.(5 marks)