Code:
AT14
Subject: IMAGE PROCESSING & COMPUTER GRAPHICS
Time: 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 best alternative in the following: (2x10)
a. This technique involves splitting a raster scan pattern into two separate patterns
(A) Random scan (B) Persistence
(C) Raster scan (D) Interlacing
b. The general form of a scaling matrix with respect to a fixed point P(h,k) and scaling parameters a and b is
(A) 
(B) 
(C)
(D) 
c. In this method, visibility is decided point by point at each pixel position on the projection plane.
(A) Image Space Method (B) Object Space Method
(C) Binary Space Partitioning (D) Back Face Method
d. The mirror image is generated by rotating the object 180° about the axis. This is termed as ___________
(A) Translation (B) Rotation
(C) Reflection (D) Scaling
e. The point at which a set of projected parallel lines appears to converge is called as a
(A) View point (B) Projection point
(C) Vanishing point (D) Parallel point
f. The waves used for imaging in radar
(A) Microwave (B) Infrared
(C) Visible (D) Ultraviolet
g. After histogram equalization, the output is characterized by this probability density function
(A) Rayleigh (B) Uniform
(C) Exponential (D) Gaussian
h. This spatial lowpass filter does not have ringing
(A) Ideal filter (B) Butterworth filter
(C) Gaussian filter (D) Exponential filter
i. This consists of generating a sharp image by subtracting from an image a blurred version of itself
(A) High boost filtering (B) High frequency emphasis
(C) Laplacian (D) Unsharp masking
j. Most devices that deposit colored pigments on paper, such as color printers and copiers require this color model.
(A) CMY and CMYK (B) RGB
(C) YIQ (D) HSI
Answer any FIVE Questions out of EIGHT Questions.
Each question carries 16 marks.
Q.2 a. Explain flat-panel displays with suitable diagrams. Indicate the different types of flat-panel displays with their applications. (8)
b. Explain the steps involved in the digital differential analyzer line drawing algorithm. Using this algorithm enumerate the steps required for drawing a line from (0, 0) to (5, 5). (8)
Q.3 a. Show that two-dimensional scale and rotation do not commute that is, scaling followed by rotation is not equivalent to rotation followed by scaling. (8)
b. Describe the Cohen-Sutherland subdivision line clipping algorithm. Consider the window with diagonally opposite edges (1, –1) and (–1, 1). Find out the status of the line P1P2 where point P1 is (–3/2, 1/6) and point P2 is (1/2, 3/2) using the algorithm. Also find the intersection of the line P1P2 with the edges of the window. (8)
Q.4 a. Explain and derive the three dimensional transformation matrix for the following:
(i) Reflection relative to the xy plane
(ii) Shear with respect to the z axis (8)
b. Derive the transformation matrix that transforms world coordinates to viewing coordinates. (8)
Q.5 a. What is meant by projection? Define the following projections:
(i) Parallel (ii) Perspective.
(iii) Orthographic (iv) Oblique
(v) Axonometric (vi) Isometric
(vii) Cabinet (8)
b. What are visible surface detection algorithms? Explain the following surface detection algorithms (i) Back face detection (ii) Depth buffer method. (8)
Q.6 a. Explain spatial and gray level resolution concepts. Describe the effects of reduced spatial and gray level resolution. (8)
b. What is the purpose of a color model? Explain HSI color model and provide the equations for converting colours from RGB to HSI and HSI to RGB. (8)
Q.7 a. Explain how spatial filtering is performed on images. Describe the following smoothing filters (i) Linear filters (ii) Median filters (8)
b. Consider a lowpass spatial filter that averages the four immediate neighbors of a point (x, y) excluding the point itself. Find the equivalent filter H(u, v) in the frequency domain. Prove that the result is a lowpass filter. (8)
Q.8 a. Encode the sequence abccd using the arithmetic coding algorithm. The probability model is a – 0.2, b – 0.2, c – 0.4 and d – 0.2. (8)
b. Explain the JPEG image compression algorithm with a block diagram. (8)
Q.9 a. Segment the image shown by using the split and merge procedure. Let P(Ri) = TRUE if all pixels in Ri have the same gray level. Show the quadtree corresponding to the segmentation. (8)
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b. Explain how Hough transform is used for global processing. (8)