Quiz
data compression
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Fragen in diesem Quiz (50)
1Which of the following characterizes a quantizer
- AQuantization results in a non-reversible loss of information
- BA quantizer always produces uncorrelated output samples
- CThe output of a quantizer has the same entropy rate as the input
- DNone of the above
2What is the signal-to-noise ratio (SNR)?
- AThe ratio of the average squared value of the source output and the squared error of the source output
- BThe ratio of the average squared value of the source output and the mean squared error of the source output
- CThe ratio of the average squared value of the source output and the absolute difference measure of the source output
- DNone of the above
3The output signal of a scalar quantizer has property
- AThe output is a discrete signal with a finite symbol alphabet
- BThe output is a discrete signal with a countable symbol alphabet (but not necessarily a finite symbol alphabet)
- CThe output signal may be discrete or continuous
- DNone of the above
4What is a Lloyd quantizer?
- AFor a given source, the Lloyd quantizer is the best possible scalar quantizer in ratedistortion That means, there does not exist any other scalar quantizer that yields a smaller distortion at the same rate.
- BThe output of a Lloyd quantizer is a discrete signal with a uniform pmf
- CBoth (A) and (B)
- DA Lloyd quantizer is the scalar quantizer that yields the minimum distortion for a given source and a given number of quantization
5Which of the following statement is correct for comparing scalar quantization and vector quantization?
- AVector quantization improves the performance only for sources with memory. For iid sources, the best scalar quantizer has the same efficiency as the best vector quantizer
- BVector quantization does not improve the rate-distortion performance relative to scalar quantization, but it has a lower complexity
- CBy vector quantization we can always improve the rate-distortion performance relative to the best scalar quantizer
- DAll of the above
6If {x}n is the source output and {y}n is the reconstructed sequence, then the squared error measure is given by
- Ad(x, y) = (y – x)^2
- Bd(x, y) = (x – y)^2
- Cd(x, y) = (y + x)^2
- Dd(x, y) = (x – y)^4
7If {x}n is the source output and {y}n is the reconstructed sequence, then the absolute difference measure is given by
- Ad(x, y) = |y – x|
- Bd(x, y) = |x – y|
- Cd(x, y) = |y + x|
- Dd(x, y) = |x – y|2
8The process of representing a ______possibly infinite set of values with a much _______set is called quantization
- ALarge, smaller
- BSmaller, large
- Clarge, large
- DNone of these
9The set of inputs and outputs of a quantizer can be
- AOnly scalars
- BOnly vectors
- CScalars or vectors
- DNone of these
10Which of the folowing is/are correct for uniform quantizer
- AThe simplest type of quantizer is the uniform quantizer
- BAll intervals are the same size in the uniform quantizer, except possibly for the two outer intervals
- CThe decision boundaries are spaced evenly
- DAll of the above
11If a Zero is assigned a decision level, then what is the type of quantizer?
- AA midtread quantizer
- BA midrise quantizer
- CA midtreat quantizer
- DNone of the above
12If a Zero is assigned a quantization level, then what is the type of quantizer?
- AA midtread quantizer
- BA midrise quantizer
- CA midtreat quantizer
- DNone of the above
13The main approaches to adapting the quantizer parameters:
- AAn off-line or forward adaptive approach
- BAn on-line or backward adaptive approach
- CBoth
- DNone of the above
14Uniform quantizer is also called as
- ALow rise quantizer
- BHigh rise quantizer
- CMid rise quantizer
- DNone of the above
15The spectral density of white noise is .
- APoisson
- BExponential
- CUniform
- DGaussian
16Which audio/video refers to on-demand requests for compressed audio/video files?
- AStreaming live
- BStreaming stored
- CInteractive
- DNone of the above
17According to Nyquist theorem, how many times the highest frequency we need to sample an analog signal?
- AThree
- BTwo
- CFour
- DNone of the above
18The minimum sampling rate is called?
- AData rate
- Bsymbol rate
- CNyquist rate
- DNone of the above
19Spread spectrum is used for
- AEncrypting signal
- BHiding signal
- CEncrypting & Hiding signal
- DNone of the mentioned
20Which is a quantization process?
- ARounding
- BTruncation
- CRounding & Truncation
- DNone of the mentioned
21 Quantization is a……………..process
- ANon linear
- BReversible
- CNon linear & Reversible
- DNone of the mentioned
22The mutual information between a pair of events is
- APositive
- BNegative
- CZero
- DAll of the mentioned
23The SNR value can be increased by the number of levels.
- AIncreasing
- BDecreasing
- CDoes not depend on
- DNone of the mentioned
241 bit quantizer is a
- AHard limiter
- BTwo level comparator
- CHard limiter & Two level comparator
- DNone of the mentioned
25The low pass filter at the output end of delta modulator depends on
- AStep size
- BQuantization noise
- CBandwidth
- DNone of the mentioned
26Quantization Matrix in JPEG compression was introduced because
- AIt is computationally more efficient to work with matrix than with scalar quantization
- BIt allows better entropy encoding due to DC and AC coefficient distribution in the 8×8 block matrix
- CIt allows better differentiation of DC and AC coefficients in the 8×8 block matrix than a scalar quantization
27What property has the output signal of a scalar quantizer
- AThe output is a discrete signal with a countable symbol alphabet (but not necessarily a finite symbol alphabet).
- BThe output is a discrete signal with a finite symbol
- CThe output signal may be discrete or continuous
28Characteristic of a vector quantizer
- AMultiple quantization indexes are represented by one codeword
- BEach input symbol is represented by a fixed-length codeword
- CMultiple input symbols are represented by one quantization index
- DAll of the above
29Vector quantization is rarely used in practical applications, why?
- AThe coding efficiency is the same as for scalar quantization
- BThe computational complexity, in particular for the encoding, is much higher than in scalar quantization and a large codebook needs to be stored
- CIt requires block Huffman coding of quantization indexes, which is very complex
- DAll of the above
30Let N represent the dimension of a vector quantizer. What statement about the performance of the best vector quantizer with dimension N is correct?
- AFor N approaching infinity, the quantizer performance asymptotically approaches the rate- distortion function (theoretical limit)
- BBy doubling the dimension N, the bit rate for the same distortion is halved
- CThe vector quantizer performance is independent of N
- DAll of the above
31Which of the following is/are correct for the advantage of vector quantization over scalar quantization.
- AVector Quantization can lower the average distortion with the number of reconstruction levels held constant
- BVector Quantization can reduce the number of reconstruction levels when distortion is held constant
- CVector Quantization is also more effective than Scalar Quantization When the source output values are not correlated
- DAll of the above
32Vector quantization is used for
- ALossy data compression
- BLossy data correction
- CPattern recognition
- DAll of the above
33The Linde–Buzo–Gray algorithm is a ___________quantization algorithm to derive a good codebook.
- AScalar
- BVector
- CBoth
- DNone of the above
34Vector quantization is used in
- AVideo coding
- BAudio coding
- CSpeech coding
- DAll of the above
35What are processes (Techniques) used in video coding?
- APartition of frames into macroblocks
- BForm of Vector Quantization
- CBoth (A) & (B)
- DNone of these
36The process of converting the analog sample into discrete form is called
- AModulation
- BMultiplexing
- CQuantization
- DSampling
37 The sequence of operations in which PCM is done is
- ASampling, quantizing, encoding
- BQuantizing, encoding, sampling
- CQuantizing, sampling, encoding
- DNone of the above
38To convert a continuous sensed data into Digital form, which of the following is required?
- ASampling
- BQuantization
- CBoth Sampling and Quantization
- DNeither Sampling nor Quantization
39For a continuous image f(x, y), Quantization is defined as
- ADigitizing the coordinate values
- BDigitizing the amplitude values
- CAll of the mentioned
- DNone of the mentioned
40The resulting image of sampling and quantization is considered a matrix of real numbers. By what name(s) the element of this matrix array is called
- AImage element or Picture element
- BPixel or Pel
- CAll of the mentioned
- DNone of the mentioned
41Which conveys more information
- AHigh probability event
- BLow probability event
- CHigh & Low probability event
- DNone of the mentioned
42The probability density function of the envelope of narrow band noise is
- AUniform
- BGaussian
- CRayleigh
- DRician
43Which model is known as ignorance model?
- APhysical model
- BMarkov model
- CProbability model
- DComposite Source Model
44Shannons theorem is also called
- Anoiseless coding theorem
- Bnoisy coding theorem
- Ccoding theorem
- Dnoiseless theorem
45Expansion of LZW Coding is
- ALossy
- BLossless
- CLempel-ziv
- DLempel-ziv-welsh
46Compression Technique used in Audio is
- ADifferential Encoding
- BTransformation Encoding
- CEntropy Coding
- DDifferential & Transformation Encoding
47__________is normally used for the data generated by scanning the documents, fax machine, typewriters etc.
- AHuffman Coding
- BTransformation Coding
- CVector Quantization
- DRunlength Encoding
48Compression Technique used in Image Video is
- AHuffman Coding
- BTransformation Coding
- CEntropy Coding
- DDifferential Encoding
49Transform coding, vector quantization are examples for
- APixel
- Bcompression
- CTransmission
- DLossy compression
50 Expansion of LZ Coding is
- ALossy
- BLossless
- CLempel-ziv-welsh
- DLempel-ziv
Informationen
- Beschreibung
- CSE Engineering Quiz am data compression, erstellt von Rajat Arya am 14/07/2021.
- Autor
- Rajat Arya
- Sprache
- English
- Aufrufe
- 138
- Schlagwörter
- Bewertung
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