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(comp344)[2007](f)final~PPSpider^_10206.pdf
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COMP344 Digital Image Processing
Fall 2007
Final Examination

Time allowed: 3 hours

Name
Student ID
Email




Question 1
Question 2
Question 3

Question 4




Question 5
Question 6
Question 7
Question 8


Total
With model answer



HK University of Science and Technology Page: 1 of 19
Course Code : COMP344 Section No.: ALL Time Allowed : 3 Hour(s)
Course Title : Digital Image Processing Total Number of Pages : 19

Time allowed: 3 hours
Answer all questions.
Thetotal markforthisquizis100.
Thisisa closed-bookquiz.

1. a) IntheHoughTransform, apoint(x0,y0)in the xy-plane is mapped into a curve in the (,)-parameter space. Write down the equation of the curve. (2 marks)
1. b) If we apply the Hough transform on the image below, what would be the maximum valueforthe accumulator cellinthe(,) space? Whatisthe corresponding(,) value? (5 marks)
Note: each black square denotes a point and the numbers are the coordinates.

HK University of Science and Technology Page: 2 of 19
Course Code : COMP344 Section No.: ALL Time Allowed : 3 Hour(s)
Course Title : Digital Image Processing Total Number of Pages : 19

Answer to question 1:
1. a) xcos()+ysin()=

1.
b) The maximum value is 8, corresponding to the horizontal line with vertical coordinate 5, because there are 8 points lying on this line. This line has the parameter =5, = /2.

2.
a) Suppose thatbothimages areblurred with a33smoothing mask. Would the resultant histogramsstillbethesame?Drawthetwohistogramsand explainyouranswer. (5 marks)


HK University of Science and Technology Page: 3 of 19
Course Code : COMP344 Section No.: ALL Time Allowed : 3 Hour(s)
Course Title : Digital Image Processing Total Number of Pages : 19

2) The two texture images shown below are quite di.erent, but their histograms are identical. Both images have size 80 80, withblack(0) and white(1) pixels.

Note: the black lines are used to signify the boundaries of the two images but not part of them.
HK University of Science and Technology Page: 4 of 19
Course Code : COMP344 Section No.: ALL Time Allowed : 3 Hour(s)
Course Title : Digital Image Processing Total Number of Pages : 19

2. b) Forimage(b),computetheco-occurrencematrixcorresponding totheproperty apixel tothe right. Eachgrid(black or white) inimage(b) is of size10 10.
(5 marks)
Answer to question 2:

2. a) the histograms will no longer be the same. They are plotted as follows
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0

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0 0.5 10 0.5 1
ab
2880 280
2.
b) The co-occurrence matrix is .

3.
a) Given a sequence of {(xi,yi)}ni=1 lying on the object boundary, brie.y describe how to obtain its Fourier descriptor? Why is the Fourier descriptor capable of dealing with noisy boundaries? (8 marks)


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