Digital Image Processing MCQ (Multiple Choice Questions)

Digital Image Processing MCQ (Multiple Choice Questions and Answers with Solutions)
Here In this article, we will discuss about the most commonly asked MCQ Multiple Choice Questions related to Digital Image Processing.

50+ MCQ’s Questions of digital Image Processing mcq question 2021 – Image processing is a method to perform some operations on an image, in order to get an enhanced image or to extract some useful information from it.

The main purpose of this article is to target College university exams, competitive exams and interviews. Here, In this Article we will cover all the asked Digital Image Processing questions mcq with the correct choice of answer with solutions.

1) At what points, a continuous image is digitized?


Answer: a) Sampling points

Explanation: Sampling is a process of reducing continuous-time signals to discrete-time signals.

2) __ represents the transition between image function’s continuous values and its digital equivalent.

d)None of the above

Answer: a) Quantization

Explanation: Quantization is a mechanism that involves the conversion of a continuous range of values into a finite range of discrete values.

3) Which of the following correctly describes the slightest visible change in the level of intensity?

d)Intensity Resolution

Answer: d) Intensity Resolution

Explanation: Intensity resolution can be defined as the total number of bits required to quantize an image.

4) What is the name of the tool that helps in zooming, shrinking, rotating, etc.?

d)None of the above

Answer: b) Interpolation

Explanation: Interpolation is one such basic tool that is used to zoom, shrink, rotate, etc.

5) The dynamic range of the imaging system is a quantitative relation where the upper limit can be determined by


Answer: c) Saturation

Explanation: Saturation is taken as a numerator.

6) The lower limit of the dynamic range ratio can be determined by


Answer: d) Noise

Explanation: Noise is taken as a denominator.

7) Which of the following is the most famous single sensor utilized for image acquisition?

d)None of the above

Answer: a) Photodiode

Explanation: The photodiode is a p-n junction semiconductor device that transmutes the light into an electric current.

8) What is the full form of CAT in image processing?

a)Computer-Aided Tomography
b)Computer-Aided Telegraphy
c)Computerized Axial Tomography
d)Computerized Axial Telegraphy

Answer: c) Computerized Axial Tomography

Explanation: Computerized Axial Tomography is based on image acquisition that uses sensor strips.

9) What is meant by the section of the real plane that the image coordinates have spanned?

a)Coordinate Axis
b)Plane of Symmetry
c)Spatial Domain
d)None of the above

Answer: c) Spatial Domain

Explanation: Spatial Domain refers to the section of the real plane that has been spanned by the coordinates of an image, where x and y coordinates are called Spatial coordinates.

10) Which of the following is the effect of using an inadequate amount of intensity levels in a digital image’s smooth areas?

c)Gaussian smooth
d)False Contouring

Answer: d) False Contouring

Explanation: False contouring is caused when the grey-level resolution of a digital image gets decreased.

11) What is the name of the process in which the known data is utilized to evaluate the value at an unknown location?

d)None of the above

Answer: a) Interpolation

Explanation: Interpolation is a process that is employed in image resampling models for assessing unfamiliar locations.

12) Which of the following is not a correct example of Image Multiplication?

b)Shading Correction
d)Region of Interest Operations

Answer: c) Pixelation

Explanation: Pixelation deals with the amplification of pixels.

13) Name the procedure in which individual pixel values of the digital image get altered.

a)Neighborhood Operations
b)Image Registration
c)Geometric Spatial Transformation
d)Single Pixel Operation

Answer: d) Single Pixel Operation

Explanation: It is expressed as a transformation function T of the form s=T(z), where z is the intensity.

14) Which of the following possess maximum frequency?

a)Gamma Rays
b)UV Rays
d)Radio waves

Answer: a) Gamma Rays

Explanation: Gamma rays are comprised of high-energy photons, which means gamma rays have the highest EM radiations. In the electromagnetic spectrum, “Gamma ray” is an arbitrary technology that encompasses a frequency above 300 EHz, 1 pm wavelength, and energy of 1.24 MeV.

15) Which of the following color possess the longest wavelength in the visible spectrum?


Answer: b) Red

Explanation: In the visible spectrum, red has the longest wavelength. The visible colors are ranged from shortest to longest wavelength, i.e., Violet, Blue, Green, Yellow, Orange, and Red.

16) What is the relationship between wavelength and frequency?

a)frequency = wavelength / c
b)c = wavelength / frequency
c)c = wavelength * frequency
d)wavelength = c * frequency

Answer: c) c = wavelength * frequency

Explanation: In general, the wavelength is calculated as wavelength = c / frequency, which means the higher the frequency, the lower the wavelength. In simple words, frequency is inversely proportional to the wavelength.

17) _ can be visualized as an electromagnetic wave.

a)cosine wave
b)sine wave
c)tangential wave
d)None of the above

Answer: b) sine wave

Explanation: Electromagnetic waves can be visualized as a sinusoidal wave.

18) How to carry out an array function together with one or more images?

a)Pixel by Pixel
b)Column by Column
c)Array by Array
d)Row by Row

Answer: a) Pixel by Pixel

Explanation: The array function is carried out on a pixel-by-pixel basis.

19) What is the name of the property that indicates the output of linear operation (i.e., the sum of two inputs) similar to that of operation first being performed on individual inputs and then summing up the respective outcomes?

d)None of the above

Answer: c) Additivity

Explanation: Additivity: f (a + b) = f (a) + f (b)

20) What is the real-world application of image subtraction?

a)MRI scan
b)CT scan
c)Mask mode radiography
d)None of the above

Answer: c) Mask mode radiography

Explanation: Mask mode radiography is an important application of medical imaging in the area of image subtraction.

21) What is meant by Region of Interest (ROI) operations?

c)Shading correction
d)None of the above

Answer: b) Masking

Explanation: In image processing, masking is a procedure of defining a smaller image, which helps modify the larger image.

22) If each element of set X is also an element of set Y, then X can be called __ of set Y.

d)Complement Set

Answer: b) Subset

Explanation: If all the elements of set X are contained in set Y, then X will be called a subset of Y.


X ⊆ Y

23) Blurring an image with the help of a smoothing filter may lead to noise reduction.


Answer: a) True

Explanation: Noise reduction is obtained by blurring the image using a smoothing filter. Blurring is used in pre-processing steps, such as removing small details from an image prior to object extraction and bridging small gaps in lines or curves.

24) What is the output of a smoothing, linear spatial filter?

a)Median of pixels
b)Maximum of pixels
c)Minimum of pixels
d)Average of pixels

Answer: d) Average of pixels

Explanation: The output or response of smoothing, the linear spatial filter, is simply the average of the pixels contained in the neighborhood of the filter mask.

25) A smoothing filter can also be called a median filter.


Answer: b) False

Explanation: A smoothing filter is used to calculate the average of the filter, which is the only reason it is called an average filter.

26) Smoothing filter is used to remove __ from an image.

a)Smooth transitions of brightness levels
b)Smooth transitions of grey levels
c)Sharp transitions of brightness levels
d)Sharp transitions of grey levels.

Answer: d) Sharp transitions of grey levels

Explanation: The smoothing filter helps in substituting each pixel value of an image by computing the average value of grey levels, which will further remove the sharp transitions in the grey levels amid the pixels. This is just to randomize noise that consists of sharp transitions in the grey level.

27) Which of the following is the disadvantage of a smoothing filter?

a)Blur inner pixels
b)Blur edges
c)Sharp edges
d)Remove sharp transitions

Answer: b) Blur edges

Explanation: Edges are one of the most desirable features that can be categorized by sharp transitions in the grey levels. Thus, average filters blur the edges, causing unwanted side effects on the image.

28) A smoothing spatial filter cannot smooth the false contour.


Answer: b) False

Explanation: The smoothing spatial filter removes the false contour that is caused due to an insufficient number of grey levels.

29) Which of the following is the correct application of image blurring?

a)Gross representation
b)Object motion
c)Object detection
d)Image segmentation

Answer: a) Gross representation

Explanation: The main purpose of gross representation is to blur the image, which is one of the most significant applications of spatial averaging. This is just to intensify the small objects combined with the background and large objects so that they can be easily identified.

30) Median filters belong to which category of filter?

a)Frequency Domain Filter
b)Order Static Filter
c)Linear Spatial Filter
d)Sharpening Filter

Answer: b) Order Static Filter

Explanation: The median filter belongs to the order static filter, which substitutes the pixel value by the median of grey level that exists in the neighborhood of the pixel.

31) Which of the following is the correct representation of log transformation?


Answer: b) s=clog10(1+r)

Explanation: In general, log transformation can be formulized as; s=clog10(1+r), where c is constant and r ≥ 0.

32) Which of the following the general representation of power transformation?

a)c = sry
b)s = rcy
c)s = cry
d)s = rc

Answer: c) s = cry

Explanation: The power-law transformation can be mathematically derived as; s = cry, where c and g represent the positive constants. However, we can write the same equation in another way, such as s=c. (r + ε) γ, which represents an offset.

33) Which of the following requires to specify the information at the time of input?

a)Power transformation
b)Log transformation
c)Linear transformation
d)Piece-wise transformation

Answer: d) Piece-wise transformation

Explanation: Piece-wise transformation plays a vital role while formulating some other transformations. Its only disadvantage is that it requires a considerable number of inputs.

34) A second order derivative operator can be defined as __.

d)None of the above

Answer: a) Laplacian

Explanation: Laplacian is the second-order derivative operator.

35) Which of the following is used to resolve the dark features in the image?

a)Gaussian Transform
b)Laplacian Transform
c)Power-law Transformation
d)Histogram Specification

36) What is the smallest possible value of the gradient image?


Answer: b) 0

Explanation: The smallest possible value of the gradient image is 0.

37) Which of the following filter possess lower frequency?

a)High pass filter
b)Bandpass filter
c)Low pass filter
d)None of the above

Answer: c) Low pass filter

Explanation: A low pass filter passes a low frequency.

38) What is the name of the process that moves a filter mask over the image, followed by calculating the sum of products?

c)Linear spatial filtering
d)Non-linear spatial filtering

Answer: a) Correlation

Explanation: Correlation can be defined as the process of moving a filter, which is often denoted as a kernel over the image to compute the sum of products at each distinct location.

39) Which of the following fact is true for an image?

a)An image is the subtraction of the illumination component from the reflectance component.
b)An image is the multiplication of the illumination and reflectance component.
c)An image is the addition of illumination and reflectance component
d)An image is the subtraction of the reflectance component from the illumination component

Answer: b) An image is the multiplication of illumination and reflectance component

Explanation: An image can be expressed as the multiplication of illumination and reflectance components.

40) Which of the following operations is used in homographic filtering for converting the input image to discrete Fourier transformed function?

a)Exponential Function
b)Logarithmic Function
c)Negative Function
d)None of the above

Answer: b) Logarithmic Function

Explanation: An image can be expressed as the multiplication of illumination and reflectance component i.e. f(x, y) = i(x, y) * r(x, y). The equation can’t be used directly to operate separately on the frequency component of illumination and reflectance because the Fourier transform of the product of two function is not separable. So, the logarithmic operation is used. I{z(x,y)}=I{ln(f(x,y)) }=I{ln(i(x,y)) }+I{ln(r(x,y))}.

41) What is the name of the class that accepts an image’s separation of luminesce and reflectance component?

a)Homomorphic system
b)Base class system
c)Base separation system
d)All of the above

Answer: a) Homomorphic system

Explanation: A homomorphic system is the only class of a system that helps achieve the separation of luminesce and reflectance components of an image.

42) Which of the following image component abruptly diverges at a certain junction of distinct objects?

a)Reflectance component
b)Illumination component
c)Both (a) and (b)
d)None of the above

Answer: b) Reflectance component

Explanation: Whenever an object reflects some light onto the scene, then the total amount of light that has been mirrored is termed as the reflectance component.

43) Given an intensity level [0, L-1] with “r” and “s” positive values, how will the negative of an image obtain?

a)s = L – 1 – r
b)s = L – 1 + r
c)s = L + 1 – r
d)s = L + 1 + r

Answer: a) s = L – 1 – r

Explanation: The negative of an image will be obtain by s = L – 1 – r.

44) In general, the log transformation can be represented by _

a)s = c.log (1 – r)
b)s = c – log (1 – r)
c)s = c.log (1 + r)
d)s = c + log (1 + r)

Answer: c) s = c.log (1 + r)

Explanation: The general form of log transformation is s = c.log (1 + r).

45) Which of the following is the correct definition of Gamma correction?

a)Light brightness variation
b) Power-law response phenomenon
c)Inverted intensity curve
d)None of the above

Answer: b) A Power-law response phenomenon

Explanation: In order to compensate for the effects of non-linear luminance, the gamma correction function maps the levels of luminance, where γ refers to a constant, i.e., gamma, and “^” is the power operator.

46) What is the name of the process that highlights an image’s intensity?

a)Intensity Highlighting
b)Intensity Matching
c)Intensity Slicing
d)None of the above

Answer: c) Intensity Slicing

Explanation: Intensity Slicing is a process of highlighting the intensity of an image.

47) What is the name of the process, which reverses the image’s intensity?

a)Piecewise Linear Transformations
b)Image Negatives
c)Log Transformations
d)None of the above

Answer: b) Image Negatives

Explanation: Image negatives utilize the reverse of image intensity.

48) Which of the following grey level intensities help in increasing the grey levels dynamic range in the image?

a)Contrast Stretching
b)Negative Transformations
c)Power-law Transformations
d)None of the above

Answer: a) Contrast Stretching

Explanation: Contrast stretching is a process of augmenting an image’s quality, which improves its contrast by stretching.

49) What is the main idea behind grey-level slicing?

a)For brightening the relevant grey-valued pixels and preserving the background
b)To give all grey levels of a specific range high value and a low value to all other grey levels.
c)All of the above
d)None of the above

Answer: c) All of the above

Explanation: In general, grey-level slicing includes the following two types of approaches:

The first one includes assigning all grey levels of a specific range high value and a low value to all other grey levels.
However, the second approach not only brightens the relevant grey-level pixel value but also preserves the background.
50) Which of the following technique is used to obtain a certain range of bits required to quantize each pixel?

b)Bit-plane slicing
c)Grey-level slicing
d)Contrast stretching

Answer: b) Bit-plane slicing

Explanation: Bit-plane slicing is one such method that represents an image with more than one bit of a byte that has been utilized for each pixel.

51) In which of the following areas can we use the low pass filters?

a)Machine perception, along with some application of character recognition
b)Printing and publishing industry
c)Satellite processing and aerial images
d)All of the above

Answer: d) All of the above

Explanation: The Lowpass filter concept is utilized in the field of character recognition, publishing, and printing industry and in the case of remotely sensed images as well by simply blurring the irrelevant data to reveal more prominent features out of the full image.

52) Which of the following act as a receptor in the retina of a human eye?

c)Both (a) and (b)
d)Neither (a) nor (b)

Answer: c) Both (a) and (b)

Explanation: Rods are long slender receptors, while cones are shorter and thicker receptors.

53) Subjective brightness is related to __

c)Image Perception
d)Image Formation

Answer: b) Intensity

Explanation: Subjective brightness is related to intensity, which is perceived by the human eye.

54) What is the name of the innermost membrane present in the human eye?


Answer: c) Retina

Explanation: The retina is the innermost membrane of the human eye.

55) What is defined by the total number of pixels within the region?


Answer: a) Area

Explanation: The total number of pixels within the region defines the area of that region. However, the perimeter refers to the boundary of the region, given the number of pixels.

56) For which of the following regions, minimal compactness is required?


Answer: a) Disk

Explanation: Since the compactness of a region is defined by 2 * (Parameter)/ Area, so the disk-shaped region encompasses minimal compactness.

57) _ is the principal factor, which helps in determining an image’s spatial resolution.

a)Dynamic range

Answer: c) Sampling

Explanation: The spatial resolution of an image can be principally determined by the process called sampling.

58) What is meant by a band-limited function?

a)A function of limited duration whose highest frequency is finite
b)A function of limited duration whose highest frequency is infinite
c)All of the above
d)None of the above

Answer: a) A function of limited duration whose highest frequency is finite

Explanation: Functions whose area under the curve is finite can be represented in terms of sines and cosines of various frequencies. The highest frequency is determined by the sine/cosine component is the highest “frequency content” of the function. If this highest frequency is finite and that the function is of unlimited duration, then these functions are called band-limited functions.

59) What is the sum of all components of a normalized histogram?

d)None of the above

Answer: a) 1

Explanation: A normalized histogram can be mathematically defined by;

p(rk) = nk / n

where n represents the total number of pixels contained in an image, rk represents the kth grey-level, and nk is the total number of pixels with grey-level rk.

60) The technique of Enhancement that has a specified Histogram processed image, as a result, is called?

a)Histogram Linearization
b)Histogram Equalization
c)Histogram Matching
d)None of the above

Answer: c) Histogram Matching

Explanation: In general, histogram specification uses a specified Histogram, i.e., the shape of the histogram can be specified by self to generate a processed image, which is also called Histogram Matching.

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