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R7909 Pages: 2

PART C

Answer any two full questions, each carries 9 marks.
Given a clipping window A(-20,-20), B(40,-20), C(40,30) and D(-20,30).
Using Cohen Sutherland line clipping algorithm, find the visible portion of
the line segment joining the points P(-30,20) and Q(60,-10).
Derive an equation for window to viewport transformation by specifying the
sequence of basic transformations involved.
What are the steps for general 3D rotation if the rotation axis is not parallel
to any one of the principal axis. The rotation axis is defined by the points
Pl(xl,yl,zl) and P2(x2,y2,z2). Write down the composite matrix
representation.
Explain Sutherland Hodgeman polygon clipping algorithm with
illustrations.
Describe the transformation which reflects a 2-D object about a line L which
has a y-intercept(0,b) and an angle of intersection theta degree w.r.t. to the x-
axis.

PART D

Answer any two full questions, each carries 12 marks.
Explain in detail the scan line algorithm for visible surface detection by
pointing out the data structures used in this algorithm..
How the cyclic overlaps of surfaces are eliminated in scan line algorithm?
In case of an A-buffer algorithm, what information is stored in a linked list.
Explain the fundamental steps in Digital Image Processing with a neat
diagram?
The gray levels in an image gl(x,y) range from a to b. It is decided to
change it into an image g2(x,y) in which the gray levels range from 61௦ 0
using a linear transformation of its gray levels. Derive the equation for
g2(x,y) as a function of g(x,y) by specifying the steps.
Explain the Robert's, Prewitt's and Sobel’s edge detectors.
Derive the transformation matrix for perspective projection with the
projection reference point at position Zprp along the Zv axis and the view
plane at Zvp. Write the perspective transformation equations (i) if the view
place is taken to be the uv plane (ii) if the projection reference point is taken

to be at the viewing co-ordinate origin.
111.

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