Spatial Filtering Fundamental MCQ [Free PDF] - Objective Question Answer for Spatial Filtering Fundamental Quiz

21. The histogram of a digital image with gray levels in the range [0, L-1] is represented by a discrete function:

A. h(r__k)=n__k
B. h(r__k )=n/n__k
C. p(r__k )=n__k
D. h(r__k )=n__k/n

Answer: A

The histogram of a digital image with gray levels in the range [0, L-1] is a discrete function h(r_k )=n_k, where r_k is the kth gray level and n_kis the number of pixels in the image having a gray level r_k.

22. How is the expression represented for the normalized histogram?

A. p(r__k )=n__k
B. p(r__k )=n__k/n
C. p(r__k)=nn__k
D. p(r__k )=n/n__k

Answer: B

It is common practice to normalize a histogram by dividing each of its values by the total number of pixels in the image, denoted by n. Thus, a normalized histogram is given by p(r_k )=n_k/n, for k=0,1,2…..L-1. Loosely speaking, p(r_k ) gives an estimate of the probability of occurrence of gray-level r_k. Note that the sum of all components of a normalized histogram is equal to 1.

23. Which of the following conditions does the T(r) must satisfy?

A. T(r) is double-valued and monotonically decreasing in the interval 0≤r≤1; and
0≤T(r)≤1 for 0≤r≤1

B. T(r) is double-valued and monotonically increasing in the interval 0≤r≤1; and
0≤T(r)≤1 for 0≤r≤1

C. T(r) is single-valued and monotonically decreasing in the interval 0≤r≤1; and
0≤T(r)≤1 for 0≤r≤1

D. T(r) is single-valued and monotonically increasing in the interval 0≤r≤1; and
0≤T(r)≤1 for 0≤r≤1

Answer: D

For any r satisfying the aforementioned conditions, we focus attention on transformations of the form
s=T(r) For 0≤r≤1
That produces a level s for every pixel value r in the original image.
For reasons that will become obvious shortly, we assume that the transformation function T(r) satisfies the following conditions:
T(r) is single-valued and monotonically increasing in the interval 0≤r≤1; and

0≤T(r)≤1 for 0≤r≤1.

24. The inverse transformation from s back to r is denoted as:

A. s=T^-1(r) for 0≤s≤1
B. r=T^-1(s) for 0≤r≤1
C. r=T^-1(s) for 0≤s≤1
D. r=T^-1(s) for 0≥s≥1

Answer: C

The inverse transformation from s back to r is denoted by:
r=T_-1(s) for 0≤s≤1.

25. Butterworth lowpass filter has a parameter, filter order, determining its functionality as a very sharp or very smooth filter function or an intermediate filter function. If the parameter value is very high, the filter approaches which of the following filter(s)?

A. Ideal lowpass filter
B. Gaussian lowpass filter
C. All of the mentioned
D. None of the mentioned

Answer: A

For the high value of filter order, the Butterworth lowpass filter behaves as an Ideal lowpass filter, while for lower order value it has a smoother form behaving like a Gaussian lowpass filter.

26. Butterworth lowpass filter has a parameter, filter order, determining its functionality as a very sharp or very smooth filter function or an intermediate filter function. If the parameter value is of a lower order, the filter approaches which of the following filter(s)?

A. Ideal lowpass filter
B. Gaussian lowpass filter
C. All of the mentioned
D. None of the mentioned

Answer: B

For the high value of filter order, the Butterworth lowpass filter behaves as an Ideal lowpass filter, while for lower order value it has a smoother form behaving like a Gaussian lowpass filter.

27. In a filter, all the frequencies inside a circle of radius D0 are not attenuated while all frequencies outside the circle are completely attenuated. The D0 is the specified non-negative distance from the origin of the Fourier transform. Which of the following filter(s) characterizes the same?

A. Ideal filter
B. Butterworth filter
C. Gaussian filter
D. All of the mentioned

Answer: A

In an ideal filter, all the frequencies inside a circle of radius D0 are not attenuated while all frequencies outside the circle are completely attenuated.

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