Applications of digital signal processing - Continuous and Discrete Time Signals and Systems - page 791

Show that the reconstruction error is greater for the second case, where
the neighboring audio samples are less correlated.

17.11 Consider the “ girl.jpg ” file provided in the accompanying CD. Read
the image using the imread function available in M ATLAB .
(a) What are the dimensions of the image stored in the “ girl.jpg ”
file?
(b) What are the maximum and minimum values of the intensity of the
pixels stored in the file?
(c) Sketch the image using the imagesc function available in
M ATLAB .
(d) Calculate and plot the 2D power spectrum of the image to illustrate
the dominant spatial frequency components of the image.

17.12 Consider the 2D filter defined by the following impulse response:

1111
1111
1111
1111

1
16

h [ m , n ] = .

(a) Show that h [ m , n ] is a lowpass filter by sketching its magnitude
spectrum using the mesh plot.
(b) Assume that the image stored in “ girl.jpg ” is applied at the
input of the filter h [ m , n ]. Determine and sketch the output image.
(c) Calculate the 2D power spectrum of the filtered image. Comparing
this with the result of Problem 17.11 (d), highlight how the high-
frequency components have been attenuated in the filtered image.

17.13 Repeat Problem 17.12 for the 2D filter with the following impulse
response:

0 . 0221

0 0

.

0 . 1563 0 . 3907 0 . 1563 0

1
3 . 2764

h [ m , n ] = 0 . 0221 0 . 3907 1 0 . 3907 0 . 0221

0 . 1563 0 . 3907 0 . 1563 0

0 . 0221 0 0

17.14 Consider the 2D filter defined by the following impulse response:

− 1 − 1 − 1

h [ m , n ] = 1
9

.

− 18 − 1
− 1 − 1 − 1

(a) Show that h [ m , n ] is a highpass filter by sketching its magnitude
spectrum using the mesh plot.
(b) Assume that the image stored in “ girl.jpg ” is applied at the
input of the filter h [ m , n ]. Determine and sketch the output image.