QUESTION 11 The zonal mask used in jpeg achieves compression by A. reducing the size of the image B. throwing away some

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QUESTION 11
The zonal mask used in jpeg achieves compression by
A.
reducing the size of the image
B.
throwing away some of the DCT coefficients
C.
increasing the number of coefficients
D.
reducing the brightness of the image
QUESTION 12
In class we considered entropy according to a zero-order model -
in other words, given a text, we considered the probability of each
character without reference to its context. What if we were to use
a first order model, in which we consider the probability of each
character given the character that appears before it? Or what if we
were to use a second order model, in which we consider the
probability of a character given the two characters before it?
Which of the following statements is true?
A.
We expect the entropy to be highest for the zero order model and
lowest for the second order model
B.
We expect the entropy would be the same for all three models
C.
We expect the entropy to be lowest for the zero order model and
highest-for the second order model
D.
We expect the entropy to be highest for the first order model
and lowest for the second order model
QUESTION 13
A Haar transform can be used to compress a signal by
A.
doing the transform multiple times
B.
stopping the transform before carrying out all the steps
C.
deleting detail coefficients that are lower than a threshold
D.
reducing the size of the signal before starting the
transform
QUESTION 14
It's easy to write a program to decode Huffman-coded messages
because
A.
Huffman codes use the same number of bits for all symbols so the
boundaries are easy to find
B.
Huffman codes are unique - there is only one possible code for
the symbols making up any signal
C.
Huffman codes possess the prefix property - the code for any
given symbol can't be the beginning of the code for another
symbol
D.
there are only a few valid Huffman codes in existence
QUESTION 15
Which of the following could be a valid Huffman code? Select all
that apply.
A.
a: 00, b: 01, c: 111, d: 100, e: 1010, f: 1011, g: 1100, h:
1101
B.
a: 11, b: 10, c: 000, d: 011, e: 0101, f: 0100, g: 0011, h:
0010
C.
a: 10, b: 100, c: 010, d: 1010, e: 1100, f: 1110, g: 1001
D.
a: 01, b: 00, c: 111, d: 110, e: 100, f: 1011, g: 1010
E.
a: 00, b: 01, c: 010, d: 011, e: 0011, f: 0001, g: 0110
QUESTION 16
The "DC" component - coefficient[0][0] - in an image DCT
corresponds to the
A.
number of pixels in the block
B.
number of operations needed to carry out the transform
C.
average brightness over the block of pixels
D.
average coefficient value
QUESTION 17
The jpeg2000 standard is
A.
based on the wavelet transform, rather than the DCT
B.
known for giving images a greenish tint
C.
not as effective as the initial jpeg standard
D.
older than the initial jpeg standard
QUESTION 18
Some speech processing algorithms use 10 ms (millisecond) blocks
of samples. How many samples are in a 10 ms block if the sample
rate is 44,100 Hz?
A.
44
B.
4
C.
441
D.
4441
QUESTION 19
Why does the jpeg standard organize its DCT coefficients in a
zigzag order?
A.
To make run length coding more efficient
B.
It makes it easier for people to read the coefficients
C.
To randomize the coefficients before further processing
D.
It restores the DCT coefficients to their most natural order
QUESTION 20
A 60 dB tone at 1000 Hz is most likely to mask which of the
following tones?
A.
20 dB at 1200 Hz
B.
20 dB at 2000 Hz
C.
20 DB at 500 Hz
D.
20 dB at 800 Hz