DATA COMPRESSION

#data

Anshu Kumar Jun 26 2021 · 22 min read
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Multiple Choice Questions 

Unit 1

  • Data compression means to the file size.
  • Increase
  • Decrease
  • Can’t say
  • None of the above Answer
  • Correct option is B

  • Data compression and encryption both work on binary
  • False
  • True Answer
  • Correct option is B

  • What is compression?
  • To compress something by pressing it very hardly
  • To minimize the time taken for a file to be downloaded
  • To reduce the size of data to save space
  • To convert one file to another Answer
  • Correct option is C

  • Data compression usually works by          .
  • Deleting random bits data
  • Finding repeating patterns Answer
  • Correct option is B

  • Why data compressed?
  • To optimise the data
  • To reduce secondary storage space
  • To reduce packet congestion on networks
  • Both (B) and (C) 
  • Correct option is D

  • Which is a type of data compression?
  • Resolution
  • Zipping
  • Inputting
  • Caching 
  • Correct option is B

  • Data compression involves
  • Compression only
  • Reconstruction only
  • Both compression and reconstruction
  • None of the above 
  • Correct option is C

  • Based on the requirements of reconstruction, data compression schemes can be divided into  broad classes
  • 3
  • 4
  • 2
  • Correct option is C

  • compression is the method which eliminates the data which is not noticeable and         compression does not eliminate the data which is not
  • Lossless, lossy
  • Lossy, lossless
  • None of these 
  • Correct option is B

  • compression is generally used for applications that cannot tolerate any difference between the original and reconstructed data.
  • Lossy
  • Lossless
  • Both
  • None of these 
  • Correct option is B

  • What is compression ratio?
  • The ratio of the number of bits required to represent the data before compression to the number of bits required to represent the data after
  • The ratio of the number of bits required to represent the data after compression to the number of bits required to represent the data before
  • The ratio of the number of bits required to represent the data after reconstruction to the number of bits required to represent the data before
  • The ratio of the number of bits required to represent the data before reconstruction to the number of bits required to represent the data after
  • Correct option is A

  • Suppose storing an image made up of a square array of 256×256 pixels requires 65,536 bytes. The image is compressed and the compressed version requires 16,384 bytes. Then the compression ratio is             .
  • 1:4
  • 4:1
  • 1:2
  • 2:1
  • Correct option is B

  • Lossy techniques are generally used for the compression of data that originate as analog signals, such as
  • Speech
  • Video
  • Both
  • None of these 
  • Correct option is C

  • If fidelity or quality of a reconstruction is , then the difference between the reconstruction and the original is .
  • High, small
  • Small, small
  • High, high
  • None of the above Answer
  • Correct option is D

  • The development of data compression algorithms for a variety of data can be divided into  
  • 2
  • 3
  • 4
  •  5 
  • Correct option is A

  • Which of the following is true of lossy and lossless compression techniques?
  • Lossless compression is only used in situations where lossy compression techniques can’t be used
  • Lossy compression is best suited for situations where some loss of detail is tolerable, especially if it will not be detectable by a human
  • Both lossy and lossless compression techniques will result in some information being lost from the original file
  • Neither lossy nor lossless compression can actually reduce the number of bits needed to represent a file
  • Correct option is B

  • Which of the following would not be suitable for Lossy Compression?
  • Speech
  • Video
  • Text
  • Image
  • Correct option is C

  • Which of the following are not in a compressed format?
  • MP3
  • Bitmap
  • MPEG
  • JPEG
  • Correct option is B

  • Information theory was given by
  • Claude von Regan
  • Claude Elwood Shannon
  • Claude Monet
  • Claude Debussy 
  • Correct option is B

  • The unit of information depends on the base of the log. If we use log base 2, the unit is ; if we use log base e, the unit is ; and if we use log base 10, the unit is                                    .
  • Hartleys, nats, bits
  • Hartleys, bits, nats
  • Bits, nats, hartleys
  • Bits, hartleys, nats
  • Correct option is C

  • According to Claude Elwood Shannon’s second theorem, it is not feasible to transmit information over the channel with error probability, although by using any coding technique?
  • Large
  • May be large or small
  • Unpredictable
  • Small 
  • Correct option is D

  • The essential condition/s for a good error control coding technique?
  • Better error correcting capability
  • Maximum transfer of information in bits/sec
  • Faster coding & decoding methods
  • All of the above 
  • Correct option is D

  • The prefix code is also called as
  • Block code
  • Convolutional code
  • Parity code
  • Instantaneous code 
  • Correct option is D

  • Self information should be .
  • Negative
  • Positive
  • Both
  • None of these 
  • Correct option is B

  • A code in which no codeword is a prefix to another codeword is called as
  • Prefix cod
  • Parity code
  • Convolutional code
  • Block code 
  • Correct option is A

  • The set of binary sequences is called a , and the individual members of the set are called             .
  • Codewords, code
  • Code, codewords
  • None of these Answer
  • Correct option is B

  • Full form of ASCII is
  • American Standard Code for Information Intercaste
  • American Standard Codewords for Information Interchange
  • American Standard Code for Information Interchange
  • American System Code for Information Interchange
  • Correct option is C

  • Composite source models is a combination or composition of several sources. In which how many source being active at any given time?
  • All
  • Only one
  • Only first three
  • None of these 
  • Correct option is B

  • For models used in lossless compression, we use a specific type of Markov process called a
  • Continous time Markov chain
  • Discrete time Markov chain
  • Constant time Markov chain
  • None of the above 
  • Correct option is B

  • Markov model is often used when developing coding algorithms for
  • Speech
  • Image
  • Both
  • None of these 
  • Correct option is C

  • Which of the following compression type is supported by SQL Server 2014?RowColumnBoth row and columnNone of the mentioned 
  • Row
  • Column
  • Both row and column
  • None of the mentioned 
  • Correct option is C

  • Point out the correct statement:
  • The details of data compression are subject to change without notice in service packs or subsequent releases
  • Compression is not available for system tables
  • If you specify a list of partitions or a partition that is out of range, an error will be generated
  • All of the mentioned
  •      Correct option is D

  • In which type of Data Compression, the integrity of the data is preserved?Lossy CompressionLossless CompressionBoth of the aboveNone of the above 
  • Lossy Compression
  • Lossless Compression
  • Both of the above
  • None of the above 
  •      Correct option is B

  • Which of the following are Lossless methods?Run-lengthHuffmanLempel ZivAll of the above
  • Run-length
  • Huffman
  • Lempel Ziv
  • All of the above
  • Correct option is D

  • Which of the following are lossy methods?JPEGMPEGMP3All of the above 
  • JPEG
  • MPEG
  • MP3
  • All of the above 
  • Correct option is D

  • In how many parts we can divide audio and video services into broad categories?TwoThreeFourNone of the above 
  • Two
  • Three
  • Four
  • None of the above 
  • Correct option is B

  • Sequence of code assigned is calledcode wordwordbytenibble
  • code word
  • word
  • byte
  • nibble
  • Correct option is A

    Unit-II  

  • Huffman codes are codes and are optimum for a given model (set of probabilities).
  • Parity
  • Prefix
  • Convolutional code
  • Block code 
  • Correct option is B

  • The Huffman procedure is based on observations regarding optimum prefix codes, which is/are 
  •      In an optimum code, symbols that occur more frequently (have a higher probability of occurrence) will have shorter codewords than symbols that occur less
  • In an optimum code,thetwo symbolsthat occurleast frequently will havethe samelength
  • Both (A) and (B)
  • None of these
  • Correct option is C

  • The best algorithms for solving Huffman codes
  • Brute force algorithm
  • Divide and conquer algorithm
  • Greedy algorithm
  • Exhaustive search 
  • Correct option is C

  • How many printable characters does the ASCII character set consists of?
  • 128
  • 100
  • 98
  • 90
  • Correct option is B

  • The difference between the entropy and the average length of the Huffman code is called
  • Rate
  • Redundancy
  • Power
  • None of these 
  • Correct option is B

  • Unit of redundancy is
  •  bits/second
  • symbol/bits
  • bits/symbol
  • none of these 
  • Correct option is C

  • The redundancy is zero when
  • The probabilities are positive powers of two
  • The probabilities are negative powers of two
  • Both
  • None of the above 
  • Correct option is B

  • Which bit is reserved as a parity bit in an ASCII set?
  • Sixth
  • Seventh
  • Eighth
  • Ninth 
  • Correct option is C

  • Bits are needed for standard encoding if the size of the character set is X
  • X+1
  • log(X)
  • X2
  • 2X 
  • Correct option is B

    10. In Huffman coding, data in a tree always occur in

  • Leaves
  • Roots
  • Left sub trees
  • None of these
  • Correct option is A

        11. An optimal code will always be present in a full tree?

  • True
  • False
  • Correct option is A

  • Running time of the Huffman encoding algorithm is
  • O(Nlog(C))
  • O(Clog(C))
  • O(C)
  • O(log(C)) Answer
  • Correct option is B

  • Running time of the Huffman algorithm, if its implementation of the priority queue is done using linked lists
  • O(log(C))
  • O(Clog(C))
  • O(C2)
  • O(C)
  • Correct option is C

  • The unary code for a positive integer n is simply n            followed by a             .
  • zero, ones
  • ones, zero
  • None of these 
  • Correct option is B

  • The unary code for 4 is          
  • 11100
  • 11110
  • 00001
  • 00011
  • Correct option is B

  • In the Tunstall code, all codewords are of However, each codeword represents a                  number of letters.
  • different, equal
  • equal, different
  • none of these
  • Correct option is B

  • Tunstall coding is a form of entropy coding used for
  • Lossless data compression
  • Lossy data compression
  • Both
  • None of these 
  • Correct option is A

  • The main advantage of a Tunstall code is that
  • Errors in codewords do not propagate
  • Errors in codewords propagate
  • The disparity between frequencies
  • None of these 
  • Correct option is A

  • Applications of Huffman Coding
  • Text compressi on
  • Audio compression
  • Lossless image compression
  • All of the above
  • Correct option is D

  • An alphabet consist of the letters A, B, C and D. The probability of occurrence is P(A) = 0.4, P(B)= 0.1, P(C) = 0.2 and P(D) = 0.3. The Huffman code is
  • A = 0 B = 111 C = 110 D = 10
  • A = 0 B = 11 C = 10 D = 111
  • A = 0 B = 111 C = 11 D = 101
  • A = 01 B = 111 C = 110 D = 10
  •   Correct option is A

  • The basic idea behind Huffman coding is      
  • compress data by using fewer bits to encode fewer frequently occuring characters
  • compress data by using fewer bits to encode more frequently occuring characters
  • compress data by using more bits to encode more frequently occuring characters
  • expand data by using fewer bits to encode more frequently occuring characters
  • Correct option is B

  • Huffman coding is an encoding algorithm used for      lossless data compressionbroadband systemsfiles greater than 1 Mbitlossy data compression
  • lossless data compression
  • broadband systems
  • files greater than 1 Mbit
  • lossy data compression
  • Correct option is A

  • A Huffman encoder takes a set of characters with fixed length and produces a set of characters ofrandom lengthfixed lengthvariable lengthconstant length 
  • random length
  • fixed length
  • variable length
  • constant length 
  • Correct option is C

  • A Huffman code: A = 1, B = 000, C = 001, D = 01 , P(A) = 0.4, P(B) = 0.1, P(C) = 0.2, P(D) = 0.3 The average number of bits per letter is
  • 0 bit
  • 1 bit
  • 0 bit
  • 9 bit 
  • Correct option is C

  • Which of the following is not a part of the channel coding?rectangular codeChecksum checkingHamming codeHuffman code 
  • rectangular code
  • Checksum checking
  • Hamming code
  • Huffman code 
  • Correct option is D

  • Which of the following is the first phase of JPEG?DCT TransformationQuantizationData CompressionNone of the above
  • DCT Transformation
  • Quantization
  • Data Compression
  • None of the above
  • Correct option is D

  • Which type of method is used is used to compress data made up of combination of symbols?Run- length encodingHuffman encodingLempel Ziv encodingJPEG encoding 
  • Run- length encoding
  • Huffman encoding
  • Lempel Ziv encoding
  • JPEG encoding 
  • Correct option is A

  • How many passes does lossy compression makes frequently?One passTwo passThree passFour pass 
  • One pass
  • Two pass
  • Three pass
  • Four pass 
  • Correct option is B

  • Information is thedatameaningful dataraw dataBoth A and B 
  • data
  • meaningful data
  • raw data
  • Both A and B 
  • Correct option is B

    Unit-III

  • In dictionary techniques for data compaction, which approach of building dictionary is used for the prior knowledge of probability of the frequently occurring patterns?
  • Adaptive dictionary
  • Static dictionary
  • Both
  • None of the above 
  • Correct option is B

  • If the probability of encountering a pattern from the dictionary is p, then the average number of bits per pattern R is given by
  • R=21-12p
  • R=9-p
  • R=21-p
  • R=12-p
  • Correct option is A

  • Static dictionary –
  • permanent
  • sometimes allowing the addition of strings but no deletions
  • allowing for additions and deletions of strings as new input symbols are being read
  • Both (A) and (B)
  • Both (A) and (C)
  • Correct option is D

  • Adaptive dictionary –
  • holding strings previously found in the input stream
  • sometimes allowing the addition of strings but no deletions
  • allowing for additions and deletions of strings as new input symbols are being read
  • Both (A) and (B)
  • Both (A) and (C) 
  • Correct option is E

  • LZ77 and LZ78 are the two algorithms published in papers by Abraham Lempel and Jacob Ziv in 1977 and 1978
  • Lossy data compression
  • Lossless data compression
  • Both
  • None of the above
  • Correct option is B

  • Deflate =………….
  • LZ78 + Huffman
  • LZ77 + Huffman
  • LZW + Huffman
  • None of these 
  • Correct option is B

  • Full form of GIF
  • Graphics Interchange Form
  • Graphics Inter Format
  • Graphics Interchange Format
  • Graphics Interact Format 
  • Correct option is C

  • LZ78 has compression but very decompression than
  • fast, slow
  • slow, fast
  • None of these 
  • Correct option is B

  • Compression packages which use an LZ77-based algorithm followed by a variable-length coder.
  • PKZip
  • Zip
  • PNG
  • All of the above
  • Correct option is D

  • Application of LZW
  • GIF
  • Zip
  • PNG
  • All of the above
  • Correct option is A

  • Algorithm used for solving temporal probabilistic reasoning
  • Depth-first search
  • Hidden markov model
  • Hidden markov model
  • Breadth-first search 
  • Correct option is C

  • Where does the Hidden Markov Model is used?
  • Understanding of real world
  • Speech recognition
  • Both
  • None of the above
  • Correct option is B

  • A coding scheme that takes advantage of long runs of identical symbols is called as
  • Move-to-front coding
  • Binary coding
  • Huffman coding
  • Move-to-back coding
  • Correct option is A

  • The idea with wavelets is to represent a complicated function bysimple basic functionssinus functionslinessquare functions 
  • simple basic functions
  • sinus functions
  • lines
  • square functions 
  • Correct option is A

  • In a typical picture, most pixels will beequalvery different to their neighborsbrightvery similar to their neighbors 
  • equal
  • very different to their neighbors
  • bright
  • very similar to their neighbors 
  • Correct option is C

  • Without losing quality, JPEG-2000 can achieve compression ratios of
  • 2:1
  • 200:1
  • 2000:1
  • 20:1
  • Correct option is B

  • The best visual compression quality is achieved usingFourier transformWaveletsDCTDolby 
  • Fourier transform
  • Wavelets
  • DCT
  • Dolby 
  • Correct option is B

  • Which is the image processing technique used to improve the quality of image for human viewing?compressionenhancementrestorationanalysis 
  • compression
  • enhancement
  • restoration
  • analysis 
  • Correct option is B

  • To remove archival compression and restore the data to column store compressionUse ALTER TABLEUse ALTER COLUMNUse ALTER DATABASEAll of the mentioned
  • Use ALTER TABLE
  • Use ALTER COLUMN
  • Use ALTER DATABASE
  • All of the mentioned
  • Correct option is A

  • Point out the wrongYou can enable or disable ROW or PAGE compression in online state onlyWhen you are compressing indexes, leaf-level pages can be compressed with both row and page compressionNon–leaf-level pages do not receive page compressionNone of the mentioned 
  • You can enable or disable ROW or PAGE compression in online state only
  • When you are compressing indexes, leaf-level pages can be compressed with both row and page compression
  • Non–leaf-level pages do not receive page compression
  • None of the mentioned 
  • Correct option is A

  • What is image?PictureMatrix of pixelCollection of pixelAll of these
  • Picture
  • Matrix of pixel
  • Collection of pixel
  • All of these
  • Correct option is D

  • An image transmitted using wireless network:corrupted as a result of lighting or other atmosphericnon-corrupted as a result of lighting or other atmosphericcorrupted as a result of pixelnone of above 
  • corrupted as a result of lighting or other atmospheric
  • non-corrupted as a result of lighting or other atmospheric
  • corrupted as a result of pixel
  • none of above 
  • Correct option is A

    Unit-IV

  • Which of the following characterizes a quantizer
  • Quantization results in a non-reversible loss of information
  • A quantizer always produces uncorrelated output samples
  • The output of a quantizer has the same entropy rate as the input
  • None of the above 
  • Correct option is A

  • What is the signal-to-noise ratio (SNR)?
  • The ratio of the average squared value of the source output and the squared error of the source output
  • The ratio of the average squared value of the source output and the mean squared error of the source output
  • The ratio of the average squared value of the source output and the absolute difference measure of the source output
  • None of the above 
  • Correct option is B

  • The output signal of a scalar quantizer has property
  • The output is a discrete signal with a finite symbol alphabet
  • The output is a discrete signal with a countable symbol alphabet (but not necessarily a finite symbol alphabet)
  • The output signal may be discrete or continuous
  • None of the above 
  • Correct option is B

  • What is a Lloyd quantizer?
  • For 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.
  • The output of a Lloyd quantizer is a discrete signal with a uniform pmf
  • Both (A) and (B)
  • A Lloyd quantizer is the scalar quantizer that yields the minimum distortion for a given source and a given number of quantization
  • Correct option is D

  • Which of the following statement is correct for comparing scalar quantization and vector quantization?
  • Vector 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
  • Vector quantization does not improve the rate-distortion performance relative to scalar quantization, but it has a lower complexity
  • By vector quantization we can always improve the rate-distortion performance relative to the best scalar quantizer
  • All of the above 
  • Correct option is C

  • If {x}n is the source output and {y}n is the reconstructed sequence, then the squared error measure is given by
  • d(x, y) = (y – x)2
  • d(x, y) = (x – y)2
  • d(x, y) = (y + x)2
  • d(x, y) = (x – y)4
  • Correct option is B

  • If {x}n is the source output and {y}n is the reconstructed sequence, then the absolute difference measure is given by
  • d(x, y) = |y – x|
  • d(x, y) = |x – y|
  • d(x, y) = |y + x|
  • d(x, y) = |x – y|2 
  • Correct option is B

  • The process of representing a           possibly infinite set of values with a much            set is called quantization
  • Large, smaller
  • Smaller, large
  • None of these
  • Correct option is A

  • The set of inputs and outputs of a quantizer can be
  • Only scalars
  • Only vectors
  • Scalars or vectors
  • None of these 
  • Correct option is C

  • Which of the folowing is/are correct for uniform quantizer
  • The simplest type of quantizer is the uniform quantizer
  • All intervals are the same size in the uniform quantizer, except possibly for the two outer intervals
  • The decision boundaries are spaced evenly
  • All of the above 
  • Correct option is D

  • If a Zero is assigned a decision level, then what is the type of quantizer?
  • A midtread quantizer
  • A midrise quantizer
  • A midtreat quantizer
  • None of the above 
  • Correct option is B

  • If a Zero is assigned a quantization level, then what is the type of quantizer?
  • A midtread quantizer
  • A midrise quantizer
  • A midtreat quantizer
  • None of the above
  • Correct option is A

  • The main approaches to adapting the quantizer parameters:
  • An off-line or forward adaptive approach
  • An on-line or backward adaptive approach
  • Both
  • None of the above 
  • Correct option is C

  • Uniform quantizer is also called as
  • Low rise quantizer
  • High rise quantizer
  • Mid rise quantizer
  • None of the above 
  • Correct option is C

  • Non uniform quantizer
  • Decrease
  • Increase
  • Doesn’t change
  • None of the above 
  • Correct option is A

  • The spectral density of white noise is .
  • Poisson
  • Exponential
  • Uniform
  • Gaussian 
  • Correct option is C

  • Which audio/video refers to on-demand requests for compressed audio/video files?Streaming liveStreaming storedInteractiveNone of the above 
  • Streaming live
  • Streaming stored
  • Interactive
  • None of the above 
  • Correct option is B

  • According to Nyquist theorem, how many times the highest frequency we need to sample an analog signal?ThreeTwoFourNone of the above
  • Three
  • Two
  • Four
  • None of the above
  • Correct option is B

  • Which encoding is based on the science of psychoacoustics, which is the study of how people perceive sound?
  • Predictive
  • Perceptual
  • Both of the above
  • None of the above
  • Correct option is B

  • SDH uses to measure block errors.CRCRectangular codebit-interleaved parity (BIP )Simple parity check
  • CRC
  • Rectangular code
  • bit-interleaved parity (BIP )
  • Simple parity check
  • The minimum sampling rate is called?Data ratesymbol rateNyquist rateNone of the above
  • Data rate
  • symbol rate
  • Nyquist rate
  • None of the above
  • Correct option is C

  • Spread spectrum is used forEncrypting signalHiding signalEncrypting & Hiding signalNone of the mentioned 
  • Encrypting signal
  • Hiding signal
  • Encrypting & Hiding signal
  • None of the mentioned 
  • Correct option is C

  • Which is a quantization process?RoundingTruncationRounding & TruncationNone of the mentioned 
  • Rounding
  • Truncation
  • Rounding & Truncation
  • None of the mentioned 
  • Correct option is C

  • . Quantization is a……………..process.Non linearReversibleNon linear & ReversibleNone of the mentioned 
  • Non linear
  • Reversible
  • Non linear & Reversible
  • None of the mentioned 
  • Correct option is C

  • The mutual information between a pair of events isPositiveNegativeZeroAll of the mentioned 
  • Positive
  • Negative
  • Zero
  • All of the mentioned 
  • Correct option is D

  • The SNR value can be increased by the number of levels.
  • Increasing
  • Decreasing
  • Does not depend on
  • None of the mentioned 
  • Correct option is A

  • 1 bit quantizer is aHard limiterTwo level comparatorHard limiter & Two level comparatorNone of the mentioned 
  • Hard limiter
  • Two level comparator
  • Hard limiter & Two level comparator
  • None of the mentioned 
  • Correct option is C

  • The low pass filter at the output end of delta modulator depends onStep sizeQuantization noiseBandwidthNone of the mentioned 
  • Step size
  • Quantization noise
  • Bandwidth
  • None of the mentioned 
  • Correct option is C

  • Quantization Matrix in JPEG compression was introduced becauseIt is computationally more efficient to work with matrix than with scalar quantization;It allows better entropy encoding due to DC and AC coefficient distribution in the 8×8 block matrix;It allows better differentiation of DC and AC coefficients in the 8×8 block matrix than a scalar quantization;
  • It is computationally more efficient to work with matrix than with scalar quantization;
  • It allows better entropy encoding due to DC and AC coefficient distribution in the 8×8 block matrix;
  • It allows better differentiation of DC and AC coefficients in the 8×8 block matrix than a scalar quantization;
  • Correct option is C

  • What property has the output signal of a scalar quantizerThe output is a discrete signal with a countable symbol alphabet (but not necessarily a finite symbol alphabet).The output is a discrete signal with a finite symbolThe output signal may be discrete or continuous
  • The output is a discrete signal with a countable symbol alphabet (but not necessarily a finite symbol alphabet).
  • The output is a discrete signal with a finite symbol
  • The output signal may be discrete or continuous
  • Correct option is A

    Unit-V

  • Characteristic of a vector quantizer
  • Multiple quantization indexes are represented by one codeword
  • Each input symbol is represented by a fixed-length codeword
  • Multiple input symbols are represented by one quantization index
  • All of the above 
  • Correct option is C

  • Vector quantization is rarely used in practical applications, why?
  • The coding efficiency is the same as for scalar quantization
  • The computational complexity, in particular for the encoding, is much higher than in scalar quantization and a large codebook needs to be stored
  • It requires block Huffman coding of quantization indexes, which is very complex
  • All of the above 
  • Correct option is B

  • Let N represent the dimension of a vector quantizer. What statement about the performance of the best vector quantizer with dimension N is correct?
  • For N approaching infinity, the quantizer performance asymptotically approaches the rate- distortion function (theoretical limit)
  • By doubling the dimension N, the bit rate for the same distortion is halved
  • The vector quantizer performance is independent of N
  • All of the above 
  • Correct option is A

  • Which of the following is/are correct for the advantage of vector quantization over scalar quantization.
  • Vector Quantization can lower the average distortion with the number of reconstruction levels held constant
  • Vector Quantization can reduce the number of reconstruction levels when distortion is held constant
  • Vector Quantization is also more effective than Scalar Quantization When the source output values are not correlated
  • All of the above
  • Correct option is D

  • Vector quantization is used for
  • Lossy data compression
  • Lossy data correction
  • Pattern recognition
  • All of the above 
  • Correct option is D

  • The Linde–Buzo–Gray algorithm is a                quantization algorithm to derive a good codebook.
  • Scalar
  • Vector
  • Both
  • None of the above 
  • Correct option is B

  • Vector quantization is used in
  • Video coding
  • Audio coding
  • Speech coding
  • All of the above
  • Correct option is C

  • What are processes (Techniques) used in video coding?
  • Partition of frames into macroblocks
  • Form of Vector Quantization
  • Both (A) & (B)
  • None of these 
  • Correct option is C

  • The process of converting the analog sample into discrete form is called
  • Modulation
  • Multiplexing
  • Quantization
  • Sampling 
  • Correct option is C

    10 . The sequence of operations in which PCM is done is

  • Sampling, quantizing, encoding
  • Quantizing, encoding, sampling
  • Quantizing, sampling, encoding
  • None of the above
  • Correct option is A

  • To convert a continuous sensed data into Digital form, which of the following is required?SamplingQuantizationBoth Sampling and QuantizationNeither Sampling nor Quantization
  • Sampling
  • Quantization
  • Both Sampling and Quantization
  • Neither Sampling nor Quantization
  • Correct option is C

  • For a continuous image f(x, y), Quantization is defined asDigitizing the coordinate valuesDigitizing the amplitude valuesAll of the mentionedNone of the mentioned
  • Digitizing the coordinate values
  • Digitizing the amplitude values
  • All of the mentioned
  • None of the mentioned
  • Correct option is B

  • The 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
  • Image element or Picture element
  • Pixel or Pel
  • All of the mentioned
  • None of the mentioned
  • Correct option is C

  • Which conveys more information?High probability eventLow probability eventHigh & Low probability eventNone of the mentioned
  • High probability event
  • Low probability event
  • High & Low probability event
  • None of the mentioned
  • Correct option is B

  • The probability density function of the envelope of narrow band noise isUniformGaussianRayleighRician
  • Uniform
  • Gaussian
  • Rayleigh
  • Rician
  • Correct option is B

  • Which model is known as ignorance model?Physical modelMarkov modelProbability modelComposite Source Model
  • Physical model
  • Markov model
  • Probability model
  • Composite Source Model
  • Correct option is C

  • Shannons theorem is also callednoiseless coding theoremnoisy coding theoremcoding theoremnoiseless theorem Answer
  • noiseless coding theorem
  • noisy coding theorem
  • coding theorem
  • noiseless theorem Answer
  • Correct option is A

  • Transform coding, vector quantization are examples forPixelcompressionTransmissionLossy compression Answer
  • Pixel
  • compression
  • Transmission
  • Lossy compression Answer
  • Correct option is D

    19.  Entropy Coding is an               

  • Lossless
  • Lossy
  • 0
  • None
  • Correct option is A

    20.                 is normally used for the data generated by scanning the documents, fax machine, typewriters etc.

  • Huffman Coding
  • Transformation Coding
  • Vector Quantization
  • Runlength Encoding
  • Correct option is D

    21.  Compression Technique used in Image Video is

  • Huffman Coding
  • Transformation Coding
  • Entropy Coding
  • Differential Encoding
  • Correct option is B

    22.  Compression Technique used in Audio is

  • Differential Encoding
  • Transformation Encoding
  • Entropy Coding
  • Differential & Transformation Encoding
  • correct option is D

    23.  Expansion of LZ Coding is

  • Lossy
  • Lossless
  • Lempel-ziv-welsh
  • Lempel-ziv
  • Correct option is D

    24.  Expansion of LZW Coding is

  • Lossy
  • Lossles
  • Lempel-ziv
  • Lempel-ziv-welsh
  • Correct option is D

    1 | 7

    1. Every run length pair introduce new

    A. pixels

    B. matrix

    C. frames

    D. intensity

    2. If the pixels are reconstructed without error mapping is said to be

    A. reversible

    B. quantization

    C. residual

    D. facsimile

    3. If the P(E) = 1, it means event

    A. does not occur

    B. always occur

    C. no probability

    D. normalization

    4. Source of information depending on finite no of outputs is called

    A. markov

    B. finite memory source

    C. zero source

    D. Both A and B

    5. Compression is done for saving

    A. storage

    B. bandwidth

    C. money

    D. Both A and B

    6. System of symbols to represent event is called

    A. storage

    B. word

    C. code

    D. nibble

    7. In the image MxN, M is

    A. rows

    B. column

    C. level

    D. intensity2 | 7

    8. Source of the event itself called

    A. zero-memory source

    B. nonzero-memory source

    C. zero source

    D. memory source

    9. Decoder is used for

    A. image enhancement

    B. image compression

    C. image decompression

    D. image equalization

    10. Replication of the pixels is called

    A. coding redundancy

    B. spatial redundancy

    C. temporal redundancy

    D. both b and c

    11. Information lost when expressed mathematically is called

    A. markov

    B. finite memory source

    C. fidelity criteria

    D. noiseless theorem

    12. Error of the image is referred to as

    A. pixels

    B. matrix

    C. frames

    D. noise

    13. Irrelevant data is said to be

    A. redundant data

    B. meaningful data

    C. raw data

    D. Both A and B3 | 7

    14. Transforming the difference between adjacent pixels is called

    A. mapping

    B. image compression

    C. image watermarking

    D. image equalization

    15. Shannons theorem is also called

    A. noiseless coding theorem

    B. noisy coding theorem

    C. coding theorem

    D. noiseless theorem

    16. Imaging system produces

    A. high resolution image

    B. voltage signal

    C. digitized image

    D. analog signal

    17. Digitizing the coordinate values is called

    A. radiance

    B. illuminance

    C. sampling

    D. quantization

    18. The first phase of JPEG

    A. DCT transformation

    B. quantization

    C.data compression

    D.none of the above

    19. The second phase of

    A. DCT transformation

    B. quantization

    C.data compression

    D.none of the above

    20. MPEG stands for____________.

    a. Multi Picture Expert Group

    b. Moving Picture Expert Group

    c. Motion Picture Expert Group

    d. None of the above

    21. Which of the following is a reversible or lossless compression technique?

    a. Hamming encoding

    b. Huffman encoding

    c. Run-length encoding

    d. Both b and c4 | 7

    22. Which of the following is not used in standard JPEG image

    compression?

    (A) Huffman coding

    (B) Runlength encoding

    (C) Zig-zag scan

    (D) K-L Transform

    23. There is a compression technique that can be used for sound files. It is

    known as ________.

    a. MPEG.

    b. MP3.

    c. GIF.

    d. JPEG.

    24. Huffman's code uses _____ encoding

     Both Variable and Fixed

     Fixed for lower Frequencies

     Fixed

     Variable

    25. How does Huffman's code accomplish data

    compression without data loss?

     Highest frequency occurrences have smallest variable codes so

    data size is larger

     Lowest frequency occurrences have largest fixed code so data size

    is smaller

     Highest frequency occurrences have smallest variable code so

    data size is smaller

     Lowest frequency occurrences have smallest fixed code so data

    size is larger

    26. What characterizes a quantizer?

    a. The output of a quantizer has the same entropy rate as the input.

    b. Quantization results in a non-reversible loss of information.

    c. A quantizer always produces uncorrelated output samples.

    d. none

    27. What property has the output signal of a scalar quantizer?

    a. The output is a discrete signal with a countable symbol alphabet (but not

    necessarily a finite symbol alphabet).

    b. The output is a discrete signal with a finite symbol alphabet.

    c. The output signal may be discrete or continuous.

    d. it provides lossless compression5 | 7

    28. What is a Lloyd quantizer?

    a. A Lloyd quantizer is the scalar quantizer that yields the minimum

    distortion for a given source and a given number of quantization intervals.

    b. The output of a Lloyd quantizer is a discrete signal with a uniform pmf.

    c. For a given source, the Lloyd quantizer is the best possible scalar quantizer in

    ratedistortion sense. That means, there does not exist any other scalar quantizer

    that yields a smaller distortion at the same rate.

    d. it provides lossless compression

    29. A Lloyd quantizer can be considered as optimal quantizer for fixed-length

    coding of the quantization indices. Can we improve a Lloyd quantizer by using

    variable length codes?

    a. No, variable length coding does not improve the quantizer performance, since

    all quantization indices have the same probability.

    b. No, variable length coding does not improve the quantizer performance, since

    the quantizer output is uncorrelated.

    c. Yes, in general, the quantizer performance can be improved by

    variable length coding (there are some exceptions for special

    sources).

    30. What characterizes the best possible scalar quantizer with variable length

    coding at high rates (for MSE distortion)?

    a. All quantization intervals have the same probability.

    b. All quantization intervals have the same size.

    c. None of the above statements is correct.

    31. What characterizes a vector quantizer?

    a. Multiple input symbols are represented by one quantization

    index.

    b. Multiple quantization indexes are represented by one codeword.

    c. Each input symbol is represented by a fixed-length codeword.

    32. What statement is correct for comparing scalar quantization and vector

    quantization?

    a. By vector quantization we can always improve the rate-distortion

    performance relative to the best scalar quantizer.

    b. Vector 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.

    c. Vector quantization does not improve the rate-distortion performance relative

    to scalar quantization, but it has a lower complexity.

    33. Why is vector quantization rarely used in practical applications?

    a. The coding efficiency is the same as for scalar quantization.

    b. It requires block Huffman coding of quantization indexes, which is very 6 | 7

    complex.

    c. The computational complexity, in particular for the encoding, is

    much higher than in scalar quantization and a large codebook needs to

    be stored.

    34. Which of the following statements is true for Lloyd quantizers:

    a. The input signal and output (reconstructed) signal are uncorrelated.

    b. The input signal and the quantization error are uncorrelated.

    c. The output (reconstructed) signal and the quantization error are

    uncorrelated.

    35. Which thing becomes a concern, when one wants to transfer files to

    another computer or storage device ?

    a) The amount of data to be transferred

    b) The form of data to be transferred

    c) Time of data to be transferred

    d) Use of data to be transferred

    36. What process is done by the data compression while encoding the data ?

    a) Identifying repetition in the data

    b) Reducing repetition in the data

    c) Eliminating repetition in the data

    d) All of these

    37. From the following for which process ‘Archive Manager tool ‘ is used ?

    a) For transferring the data of file and directory

    b) For place compression on the file and directory

    c) For altering the form of file and directory

    d) For data compression on file and directory

    38. Which is the common archive Structure of Linux ?

    a) TER

    b) TAR

    c) TET

    d) TAT

    39. From the following, which file format stores multiple files in a single Zip

    file ?

    a) zap

    b) zip

    c) zop

    d) zep

    40. Which is a type of data compression

    A. Resolution

    B. Zipping

    C. Inputting

    D. Caching7 | 7

    41. Compression is used for applications that can not tolerate any difference

    between the original and reconstructed data

    A. Lossy

    B. Lossless

    C. Both

    D. None

    42. Prefix code is also caleed as

    A. Block code

    B. Convolutional code

    C. Parity code

    D. Instantaneous code

    43. Self information should be

    A. Negative

    B. Positive

    C. Both

    D. None

    44. The set of binary sequences is called a………, and individual members of

    the set are called………….

    A. Codewords, code

    B. Code, codewords

    C. None

    48.For models used in lossless compression , we use a specific type of markov

    process called

    a. Continuous time markov chain

    b. Discrete time markov chain

    c. Constant time markov chain

    d. None

    49. Markov model is often used when developing coding algorithms for

    e. Speech

    b. Image

    c. Both

    d. None

    50.In which type of compression the integrity of data is preserved

    a. Lossy

    b. Lossless

    c. Both

    d. None

    51. Which of the following are Lossless methods?

    A. Run-length

    B. Huffman

    C. Lempel Ziv

    D. All of the abovekvk

    1. Which of the following are Lossless methods?

    A. Run-length

    B. Huffman

    C. Lempel Ziv

    D. All of the above

    2. Which of the following are lossy methods?

    A. JPEG

    B. MPEG

    C. MP3

    D. All of the above

    3. Huffman codes are codes and are optimum for a given model (set of

    probabilities).

    A. Parity

    B. Prefix

    C. Convolutional code

    D. Block code

    4. The best algorithms for solving Huffman codes

    A. Brute force algorithm

    B. Divide and conquer algorithm

    C. Greedy algorithm

    D. Exhaustive search

    5. The difference between the entropy and the average length of the

    Huffman code is called

    A. Rate

    B. Redundancy

    C. Power

    D. None of these

    6. Unit of redundancy is

    A. bits/second

    B. symbol/bits

    C. bits/symbol

    D. none of these

    7. The unary code for a positive integer n is simply n followed by a .

    A. zero, ones

    B. ones, zero

    C. None of these

    8. The unary code for 4 is .

    A. 11100

    B. 11110

    C. 00001

    D. 00011

    9. In the Tunstall code, all codewords are of…….., However, each

    codeword represents a……………. number of letters.

    A. different, equal

    B. equal, different

    C. none of these

    10. Tunstall coding is a form of entropy coding used for

    A. Lossless data compression

    B. Lossy data compression

    C. Both

    D. None of these

    11. The main advantage of a Tunstall code is that

    A. Errors in codewords do not propagate

    B. Errors in codewords propagate

    C. The disparity between frequencies

    D. None of these12. Applications of Huffman Coding

    A. Text compression

    B. Audio compression

    C. Lossless image compression

    D. All of the above

    13. Huffman coding is an encoding algorithm used for

    A. lossless data compression

    B. broadband systems

    C. files greater than 1 Mbit

    D. lossy data compression

    14. Which type of method is used is used to compress data made up of

    combination of symbols?

    A. Run- length encoding

    B. Huffman encoding

    C. Lempel Ziv encoding

    D. JPEG encoding

    15. Information is the

    A. data

    B. meaningful data

    C. raw data

    D. Caching

    16. Suppose storing an image made up of a square array of 256×256

    pixels requires 65,536 bytes. The image is compressed and the

    compressed version requires 16,384 bytes. Then the

    compression ratio is .

    A. 1:4

    B. 4:1

    C. 1:2

    D. 2:1

    17. Lossy techniques are generally used for the compression of data

    that originate as analog signals, such as

    A. Speech

    B. Video

    C. Both

    D. None of these

    18. In dictionary techniques for data compaction, which approach of

    building dictionary is used for the prior knowledge of probability of the

    frequently occurring patterns?

    A. Adaptive dictionary

    B. Static dictionary

    C. Both

    D. None of the above

    19. Static dictionary –

    A. permanent

    B. sometimes allowing the addition of strings but no deletions

    C. allowing for additions and deletions of strings as new input symbols

    are being read

    D. Both (A) and (B)

    20. Adaptive dictionary –

    A. holding strings previously found in the input stream

    B. sometimes allowing the addition of strings but no deletions

    C. allowing for additions and deletions of strings as new input symbols

    are being read

    D. Both (A) and (C)21. LZ77 and LZ78 are the two algorithms published in papers by

    Abraham Lempel and Jacob Ziv in 1977 and 1978

    A. Lossy data compression

    B. Lossless data compression

    C. Both

    D. None of the above

    22. Deflate =………….

    A. LZ78 + Huffman

    B. LZ77 + Huffman

    C. LZW + Huffman

    D. None of these

    23. LZ78 has compression but very decompression than

    A. fast, slow

    B. slow, fast

    C. None of these

    24 Compression packages which use an LZ77-based algorithm followed

    by a variable-length coder.

    A. PKZip

    B. Zip

    C. PNG

    D. All of the above

    25. Application of LZW

    A. GIF

    B. Zip

    C. PNG

    D. All of the above

    26. A coding scheme that takes advantage of long runs of identical

    symbols is called as

    A. Move-to-front coding

    B. Binary coding

    C. Huffman coding

    D. Move-to-back coding

    27. Which of the following characterizes a quantizer

    A. Quantization results in a non-reversible loss of information

    B. A quantizer always produces uncorrelated output samples

    C. The output of a quantizer has the same entropy rate as the input

    D. None of the above

    28. The set of inputs and outputs of a quantizer can be

    A. Only scalars

    B. Only vectors

    C. Scalars or vectors

    D. None of these

    29. Which of the folowing is/are correct for uniform quantizer

    A. The simplest type of quantizer is the uniform quantizer

    B. All intervals are the same size in the uniform quantizer, except

    possibly for the two outer intervals

    C. The decision boundaries are spaced evenly

    D. All of the above

    30. If a Zero is assigned a decision level, then what is the type of

    quantizer?

    A. A midtread quantizer

    B. A midrise quantizer

    C. A midtreat quantizer

    D. None of the above31. If a Zero is assigned a quantization level, then what is the type of

    quantizer?

    A. A midtread quantizer

    B. A midrise quantizer

    C. A midtreat quantizer

    D. None of the above

    32. The main approaches to adapting the quantizer parameters:

    A. An off-line or forward adaptive approach

    B. An on-line or backward adaptive approach

    C. Both

    D. None of the above

    33. Uniform quantizer is also called as

    A. Low rise quantizer

    B. High rise quantizer

    C. Mid rise quantizer

    D. None of the above

    34. Which audio/video refers to on-demand requests for compressed

    audio/video files?

    A. Streaming live

    B. Streaming stored

    C. Interactive

    D. None of the above

    35. The minimum sampling rate is called?

    A. Data rate

    B. symbol rate

    C. Nyquist rate

    D. None of the above

    36. Which is a quantization process?

    A. Rounding

    B. Truncation

    C. Rounding & Truncation

    D. None of the mentioned

    37. . Quantization is a……………..process.

    A. Non linear

    B. Reversible

    C. Non linear & Reversible

    D. None of the mentioned

    38. Characteristic of a vector quantizer

    A. Multiple quantization indexes are represented by one codeword

    B. Each input symbol is represented by a fixed-length codeword

    C. Multiple input symbols are represented by one quantization

    index

    D. All of the above

    39. Vector quantization is rarely used in practical applications, why?

    A. The coding efficiency is the same as for scalar quantization

    B. The computational complexity, in particular for the encoding, is

    much higher than in scalar quantization and a large codebook

    needs to be stored

    C. It requires block Huffman coding of quantization indexes, which is

    very complex

    D. All of the above40. Which of the following is/are correct for the advantage of vector

    quantization over scalar quantization.

    A. Vector Quantization can lower the average distortion with the number

    of reconstruction levels held constant

    B. Vector Quantization can reduce the number of reconstruction levels

    when distortion is held constant

    C. Vector Quantization is also more effective than Scalar Quantization

    When the source output values are not correlated

    D. All of the above

    41 The Linde–Buzo–Gray algorithm is a quantization algorithm to derive

    a good codebook.

    A. Scalar

    B. Vector

    C. Both

    D. None of the above

    42 Vector quantization is used in

    A. Video coding

    B. Audio coding

    C. Speech coding

    D. All of the above

    43. The process of converting the analog sample into discrete form is

    called

    A. Modulation

    B. Multiplexing

    C. Quantization

    D. Sampling

    44 . The sequence of operations in which PCM is done is

    A. Sampling, quantizing, encoding

    B. Quantizing, encoding, sampling

    C. Quantizing, sampling, encoding

    D. None of the above

    45. The probability density function of the envelope of narrow band

    noise is

    A. Uniform

    B. Gaussian

    C. Rayleigh

    D. Rician

    46. Which model is known as ignorance model?

    A. Physical model

    B. Markov model

    C. Probability model

    D. Composite Source Model

    47. Shannons theorem is also called

    A. noiseless coding theorem

    B. noisy coding theorem

    C. coding theorem

    D. noiseless theorem Answer

    48. Transform coding, vector quantization are examples for

    A. Pixel

    B. compression

    C. Transmission

    D. Lossy compression 49. …………is normally used for the data generated by

    scanning the documents, fax machine, typewriters etc.

    A. Huffman Coding

    B. Transformation Coding

    C. Vector Quantization

    D. Runlength Encoding

    50. Expansion of LZ Coding is

    A. Lossy

    B. Lossless

    C. Lempel-ziv-welsh

    D. Lempel-ziv

    51. Expansion of LZW Coding is

    A. Lossy

    B. Lossles

    C. Lempel-ziv

    D. Lempel-ziv-welc

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