91. The standard deviation ‘σ’ at any point in image averaging: σḡ(x, y) = 1/√K σɳ(x, y), where ḡ(x, y) is the average image formed by averaging K different noisy images and ɳ(x, y) is the noise added to an original image f(x, y). What is the relation between K and the variability of the pixel values at each location (x, y)?

A. Increase in K, decreases the noise of pixel values

B. Increase in K, increases the noise of pixel values

C. Decrease in K, decreases the noise of pixel values

D. Decrease in K, increases the noise of pixel values

92. A filter is applied to an image whose response is independent of the direction of discontinuities in the image. The filter is/are ________

A. Isotropic filters

B. Box filters

C. Median filter

D. All of Mentioned

93. In isotropic filtering, which of the following is/are the simplest isotropic derivative operator?

A. Laplacian

B. Gradient

C. All of Mentioned

D. None of the mentioned

94. The Laplacian is which of the following operator?

A. Nonlinear operator

B. Order-Statistic operator

C. Linear operator

D. None of the mentioned

95. A Laplacian for an image f(x, y) is given by ________

A. [f(x + 1, y) + f(x – 1, y) – 2f(x, y)] and [f(x, y + 1) + f(x, y – 1) – 2f(x, y)] respectively

B. [f(x + 1, y + 1) + f(x, y – 1) – 2f(x, y)] and [f(x , y + 1) + f(x – 1, y) – 2f(x, y)] respectively

C. [f(x, y + 1) + f(x, y – 1) – 2f(x, y)] and [f(x + 1, y) + f(x – 1, y) – 2f(x, y)] respectively

D. None of the mentioned

96. The Laplacian ∇2 f=[f(x + 1, y) + f(x – 1, y) + f(x, y + 1) + f(x, y – 1) – 4f(x, y)], gives an isotropic result for rotations in increment by what degree?

A. 90°

B. 0°

C. 45°

D. None of the mentioned

97. The Laplacian incorporated with diagonal directions, i.e. ∇2 f=[f(x + 1, y) + f(x – 1, y) + f(x, y + 1) + f(x, y – 1) – 8f(x, y)], gives an isotropic result for rotations in increment by what degree?

A. 90°

B. 0°

C. 45°

D. None of the mentioned

98. Applying Laplacian has which of the following result(s)?

A. Produces images having greyish edge lines

B. Produces image having a featureless background

C. All of Mentioned

D. None of the mentioned

99. Applying Laplacian produces an image having featureless background which is recovered maintaining the sharpness of the Laplacian operation by either adding or subtracting it from the original image depending upon the Laplacian definition used. Which of the following is true based on the above statement?

A. If the definition used has a negative center coefficient, then subtraction is done

B. If the definition used has a positive center coefficient, then subtraction is done

C. If the definition used has a negative center coefficient, then the addition is done

D. None of the mentioned

100. A mask of size 3*3 is formed using Laplacian including diagonal neighbors that have a central coefficient of 9. Then, what would be the central coefficient of the same mask if it is made without diagonal neighbors?

A. 5

B. -5

C. 8

D. -8

101. Which of the following mask(s) is/are used to sharpen images by subtracting a blurred version of the original image from the original image itself?

A. Unsharp mask

B. High-boost filter

C. All of Mentioned

D. None of the mentioned

102. Which of the following gives an expression for a high boost filtered image file, if f represents an image, f blurred version off, fs unsharp mask filtered image, and A ≥ 1?

A. fhb = (A – 1) f(x, y) + f(x, y) – f x, y)

B. fhb = A f(x, y) – f(x,y)

C. fhb = (A – 1) f(x, y) + fs(x, y)

D. All of Mentioned

102. If we use a Laplacian to obtain a sharp image for unsharp mask filtered image fs(x, y) of f(x, y) as the input image, and if the center coefficient of the Laplacian mask is negative then, which of the following expression gives the high boost filtered image fhb, if ∇2 f represent Laplacian?

A. fhb = A f(x, y) – ∇2 f(x,y)

B. fhb = A f(x, y) + ∇2 f(x,y)

C. fhb = ∇2 f(x,y)

D. None of the mentioned

103. “For a very large value of A, a high boost filtered image is approximately equal to the original image”. State whether the statement is true or false?

A. True

B. False

104. Subtracting Laplacian from an image is proportional to which of the following?

A. Unsharp masking

B. Box filter

C. Median filter

D. None of the mentioned

105. The First derivative in image processing is implemented using which of the following given operator(s)?

A. Magnitude of the Gradient vector

B. The Laplacian

C. All of Mentioned

D. None of the mentioned

106. If for an image function f(x, y), the magnitude of gradient vector is given by: mag(∇f)=[G2x+G2y] (1/2), then which of the following fact is correct?

A. The component of the Gradient vector is a linear operator and also the magnitude of the vector

B. The component of the Gradient vector is a linear operator, but the magnitude is not

C. The component of the Gradient vector are nonlinear operators and also the magnitude of the vector

D. The component of the Gradient vector are nonlinear operators, but the magnitude is not

107. What is the sum of the coefficient of the mask defined using gradient?

A. 1

B. -1

C. 0

D. None of the mentioned

108. The gradient is used in which of the following area(s)?

A. To aid humans in the detection of defects

B. As a preprocessing step for automated inspections

C. All of Mentioned

D. None of the mentioned

109. Gradients have some important features. Which of the following are/are some of them?

A. Enhancing small discontinuities in an otherwise flat gray field

B. Enhancing prominent edges

C. All of Mentioned

D. None of the mentioned

110. An image has significant edge details. Which of the following fact(s) is/are true for the gradient image and the Laplacian image of the same?

A. The gradient image is brighter than the Laplacian image

B. The gradient image is brighter than the Laplacian image

C. Both the gradient image and the Laplacian image have equal values

D. None of the mentioned