# Digital Signal And Image Processing MCQ

Question 1 : The number of complex addition in direct DFT are

1. N(N-1)
2. N^2
3. Nlog2 N
4. (N/2)log2 N

Question 2 : The circular convolution of two sequences in time domain is equivalent to

1. Multiplication of DFTs of two sequences
2. Summation of DFTs of two sequences
3. Difference of DFTs of two sequences
4. Square of multiplication of DFTs of two sequences

Question 3 : Which among the following operations is/are not involved /associated with the computation process of linear convolution?

1. Folding Operation
2. Shifting Operation
3. Multiplication Operation
4. Integration Operation

Question 4 : Human sounds cannot be characterized with which parameter

1. Pitch
2. Sensitivity
3. Loudness
4. Quality

Question 5 : Giving one period of the periodic convolution is called

1. Periodic convolution
2. Aperiodic convolution
3. Correlation
4. Circular convolution

Question 6 : First difference of smallest magnitude is called as

1. Shape number
2. Euler Number
3. Chain Code
4. Signature

Question 7 : The output signal when a signal x(n) ={0,1,2,3} is processed through an ‘Delay’ system is?

1. {1,2,3}
2. {0,1,2,3}
3. {0,0,1,2,3}
4. {2,3}

Question 8 : Zero crossing operator use the following

1. First derivative
2. Second derivative
3. Sobel operator
4. Gaussian operator

Question 9 : The overlap save method is used to calculate

1. The discrete convolution between a sampled signal and a finite impulse response (FIR) filter
2. The discrete convolution between a sampled signal and an infinite impulse response (IIR) filter
3. The discrete convolution between a very long signal and a finite impulse response (FIR) filter
4. The discrete convolution between a very long signal and a infinite impulse response (IIR) filter

Question 10 : DFT of a discrete signal is ___ in nature

1. Continuous
2. Analog
3. Discrete
4. Aperiodic

Question 11 : The 4-point DFT of {1,1,0,0} is

1. { 2, 1-j, 0, 1+j }
2. { -2, 1-j, 0, 1+j }
3. { 4, 1-j, 0, 1+j }
4. { -2, 1-j, 0, 1-j }

Question 12 : While performing negative of a 3 bpp image the pixel value '5' will transform to

1. 2
2. 5
3. 8
4. 0

Question 13 : Which of the following is not image representation technique

1. Chain Code
2. Signature
3. Shape Number
4. Dilation

Question 14 : Using gray-level transformation, the basic function linearity deals with which of the following transformation?

1. Log and inverse-log transformations
2. Negative and identity transformations
3. nth and nth root transformations
4. Power-law transformations

Question 15 : Which condition determines the causality of the LTI system in terms of its impulse response?

1. Only if the value of an impulse response is zero for all negative values of time
2. Only if the value of an impulse response is unity for all negative values of time
3. Only if the value of an impulse response is infinity for all negative values of time
4. Only if the value of an impulse response is negative for all negative values of time

Question 16 : If the impulse response the system is of infinite duration then it is called

1. FIR system
2. IIR system
3. IFR system
4. IIF system

Question 17 : If the DFT {x(n)} = X(k) = {4, –2j, 0, 2j}, using properties of DFT, DFT of x(-n) is

1. (4, 2j, 0, -2j)
2. (2j, 0, -2j,4)
3. (4, 0, 2j, -2j)
4. (0,2 j, 4, -2j)

Question 18 : Example of Region Growing Methods is

1. Level Set Methods
2. Graph Partitioning Methods
3. Watershed Transformation
4. Neural Networks Segmentation

Question 19 : Which transformations are useful for general-purpose contrast manipulation

1. Power law transformations
2. Identity transformation
3. Negative transformation
4. Logarithmic transformation

Question 20 : If a signal x(n) is passed through a system to get an output signal y(n) =x(n+1), then the signal is said to be

1. Delayed
3. No operation
4. Inversed

Question 21 : In formula G(x,y) = T[F(x,y)], T is the

1. Transformed Image
2. Transformed Vector
3. Transformation function
4. Transformation theorem

Question 22 : DFT of the sequence x(n)={ 1, -2, 3, 2}

1. {4, -2+j4, 4, -2+j4 }
2. {4, -2+j4, 4, -2-j4 }
3. {-4, -2-j4, 4, 2-j4 }
4. {4, -2-j4, -4, -2-j4 }

Question 23 : Which of these is not a property of two-dimensional DFT

1. Symmetric
2. Periodic extensions
3. Sampled Fourier transform
4. Linearity

Question 24 : Term which refers to the sharpness or clarity of an image, is------------

1. Pitch
2. Pixel
3. Resolution
4. Signal

Question 25 : The interface between an analog signal and a digital processor is

1. D/A converter
2. A/D converter
3. Modulator
4. Demodulator

Question 26 : Continuous functions are sampled to form a

1. Fourier series
2. Fourier transform
3. Fast Fourier series
4. Digital image

Question 27 : A good representation of the derivative of a step function u(t) is...

1. Another step function
2. A complex exponential
3. A ramp mt, where m is the slope.
4. A delta function δ(t)

Question 28 : To reduce the effect of aliasing high frequencies are

1. Attenuated
2. Accentuated
3. Reduced
4. Removed

Question 29 : Which filter is best to remove salt and pepper noise?

1. Low pass
2. Sobel
3. Median
4. Laplacian

Question 30 : DWT stands for

1. Discrete wavelet transform
2. Discrete wavelet transformation
3. Digital wavelet transform
4. Digital wavelet transformation

Question 31 : The Walsh and Hadamard transforms are ___________in nature

1. Sinusoidal
2. Cosine
3. non-sinusoidal
4. cosine and sine

Question 32 : Which of the following should be done in order to convert a continuous-time signal to a discrete-time signal?

1. Sampling
2. Differentiating
3. Integrating
4. Quantization

Question 33 : Run Length Encoding is used for

1. Reducing the repeated string of characters
2. Bit error correction
3. Correction of error in multiple bits
4. Increasing the repeated string of characters

Question 34 : If the DFT {x(n)} = X(k) = {4, –2j, 0, 2j}, using properties of DFT, DFT of x(n-2) is

1. (4, 2j, 0, -2j)
2. (2 j, 0, -2j, 4)
3. (4, 0, 2j, -2j)
4. (0, 2j, 4, -2j)

Question 35 : Which of the following condition should hold true for a signal x[n] to be odd?

1. x[-n] = x[n] • x[n]
2. x[n] = -x[-n]
3. x[n] = [x[n]]3
4. x[n] = x[n]

Question 36 : Computation of linear filtering of a sequence using FFT algorithm requires no. of complex additions are

1. (N/2)logN
2. 2NlogN [Base=2]
3. (N/2)logN [Base=2]
4. NlogN [Base=2]

Question 37 : If sampling frequency is below Nyquist frequency , distortion in the present sprectra due to other spectra in the frequency domain is called as ____

1. Discrete Fourier Transform
2. Nyquist – Shannon sampling theory
3. Aliasing
4. Up sampling

Question 38 : Which segmentation technique is based on clustering approaches?

1. K-means algorithm
2. Threshold based algorithm
3. Histogram based algorithm
4. Edge detection based algorithm

Question 39 : Image transforms are needed for

1. conversion information form spatial to frequency
2. spatial domain
3. time domain
4. frequency domain

Question 40 : For the Dissemination-in-time FFT algorithm, which of the following is true?

1. Both input and output are in order.
2. Both input and output are shuffled.
3. Input is shuffled and output is in order.
4. Input is in order and output is shuffled.

Question 41 : In neighborhood processing methods

1. All the pixels in the neighborhood are processed at a time
2. A pixel in the neighborhood is processed using the current pixel
3. A pixel is processed using all the pixels within the neighborhood
4. A pixel is processed using its own current value

Question 42 : Which of the following property makes it possible to calculate 2D DFT using 1D DFT?

1. conjugate symmetry
2. Separability
3. Time shift
4. Periodicity

Question 43 : Periodic property of DFT says __________

1. X( n + K )=X(K)
2. X( k +N )=X(k)
3. X( K + iN )=X(i)
4. X( N + K )=X(n)

Question 44 : If a discrete time signal x(n) of length l is convolved with a discrete time signal y(n) of length n then the length of output signal is

1. l+n-1
2. l-n+1
3. l*n
4. l*n-1

Question 45 : Convolution of two functions means rotating one function at angle of

1. 360
2. 270
3. 90
4. 180

Question 46 : Speech recognition system consists of the following except

1. Microphone
2. DAC
3. Pattern matching
4. Parameter extraction

Question 47 : DFT of a signal is a lossy process.

1. No
2. Yes
3. May be
4. No way to decide

Question 48 : Which is a colour attribute that describes a pure colour?

1. Saturation
2. Hue
3. Brightness
4. Intensity

Question 49 : 2D Fourier transform and its inverse are infinitely

1. Aperiodic
2. Periodic
3. Linear
4. Non linear

Question 50 : Under which conditions does an initially relaxed system become stable

1. only if bounded input generates unbounded output
2. only if bounded input generates bounded output
3. only if unbounded input generates unbounded output
4. only if unbounded input generates bounded output

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