CS 659图像处理图像识别

【CS 659图像处理】CS 659 Image Processing
Exam One
Name: Student ID #:
Covering Lectures 1~6. There are 4 questions. Each is 25 points.

(a) (10 points) Determine the convolution and correlation of the two sequences shown below.
Note that, black dots represent value 1 and white dots represent value 0. Underline the pixel at
the origin. Note that the answers are 4 by 4 matrices.

(b) (15 points) Perform the convolution
f g
and the correlation
f g
. Assume the origin is
located at the lower-left corner. Underline the pixel at the origin. Note that the answers are 3 by 4
matrices.
3 5 1 2 1
: , :
6 2 1 3

(a) (10 points) Apply contrast stretching to the image below using
2, 1, 5, 7. r1 = s1 = r2 = s2 =
Show your computation and the output image. Note that using rounding to be all integers.
1 0 0 0 0 0 1
1 1 1 0 1 0 1
3 4 4 5 5 0 0
3 4 4 5 5 5 5
4 4 4 4 5 7 0
1 4 5 6 5 6 1
0 4 4 1 5 6 1
0 1 1 1 0 5 0
(b) (15 points)
Let the input pixels {y(m)}={2, 3, 8, 4, 2} and the window W = [-1, 0, 1]. What is the median
filter output {v(m)}? Let W contain an even number of pixels, say W = [-1, 0, 1, 2]. What is the
median filter output {v(m)}? Note that let the boundary pixels stay the same (i.e., without the
median computation). Note that using floating-point numbers (i.e., DO NOT round into
integers).
(10 points) (a) Given a template f, find the location of exact match in the image g by using
Correlation of fg minus Correlation of f'g. Show your calculations and mark the matched
locations.
(b) (15 points) Is it possible to perform the matching by using only one correlation (f and g are
shown below)? If the answer is Yes, show the modified template and your calculations, and
mark the matched locations. If the answer is No, describe your opinion why it cannot work.
f:
1 0
0 1
1 0
g:
0 0 0 0 0 0 0
0 1 0 1 0 0 0
1 0 1 1 1 1 0
0 1 0 1 0 0 0
0 0 0 1 1 1 0
1 1 0 0 0 1 0
1 1 0 0 0 1 0
0 0 0 0 0 0 0
(25 points) Apply histogram equalization to the image below. Let the output gray levels are in
the range of [0, 7]. Show your step-by-step calculations, the input/output pixel mapping, and
the resulting output image.
1 5 5 0 0 1 0
1 2 2 0 1 0 1
7 6 6 5 5 0 0
7 6 7 5 5 5 5
7 6 7 3 5 7 0
1 4 1 6 5 6 1
2 4 1 1 5 1 1
2 2 0 0 0 0 5