OpenCV Questions and Answers – Motion Blur

This set of OpenCV Multiple Choice Questions & Answers (MCQs) focuses on “Motion Blur”.

1. What is the full form of PSF?
a) Point Spread Function
b) Point Speed Function
c) Pin Spread Function
d) Point Spread Fast
View Answer

Answer: a
Explanation: The Full Form of PSF is point spread function. The point spread function (PSF) describes the response of an imaging system to a point source or point object. PSF is a system’s impulse response.

2. Which of the following method or function is used to detects objects of different sizes in the input image and the detected objects are returned as a list of rectangles in OpenCV?
a) detectScale()
b) detectMulti()
c) detectMultiSize()
d) detectMultiScale()
View Answer

Answer: d
Explanation: detectMultiScale is a function or method that detects objects of different sizes in the input image. The detected objects are returned as a list of rectangles. The function is parallelized with the TBB (Threading Building Blocks) library.

3. Which of the following explanation is the appropriate for Negative Sample with respect to Object Detection?
a) Negative Samples are used by the boosting process to define what the model should actually look for when trying to find your objects of interest
b) Negative samples are taken from arbitrary images, not containing objects you want to detect. These negative images, from which the samples are generated, should be listed in a special negative image file containing one image path per line
c) Negative samples are taken from arbitrary images, containing objects you want to detect
d) Negative samples are not needed while training for the Haar Cascade
View Answer

Answer: b
Explanation: Negative samples are taken from arbitrary images, not containing objects you want to detect. These negative images, from which the samples are generated, should be listed in a special negative image file containing one image path per line.

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4. The Wiener filter minimizes the mean square error between the estimated random process and the desired process.
a) True
b) False
View Answer

Answer: a
Explanation: The Wiener filter is a filter used to produce an estimate of a desired or target random process by linear time-invariant (LTI) filtering of an observed noisy process. The Wiener filter minimizes the mean square error between the estimated random process and the desired process.

5. Which of the following is the restoration formula in frequency domain?
a) U′=Hw/S
b) U′=H++S
c) U′=Hw⋅S
d) U′=Hw-S
View Answer

Answer: c
Explanation: The restoration formula in frequency domain is U′=Hw⋅S where U′ is the spectrum of estimation of original image U, and Hw is the restoration filter, for example, the Wiener filter.

6. The application supports Three ways of generating a positive sample dataset.
a) True
b) False
View Answer

Answer: b
Explanation: The application supports two ways of generating a positive sample dataset. 1) Generate a bunch of positives from a single positive object image. 2) Supply all the positives yourself and only use the tool to cut them out, resize them and put them in the OpenCV needed binary format. – medium.com

7. What is the formula for the image degradation in frequency domain representation?
a) S=H⋅U-N
b) S=H/U+N
c) S=H*U*N
d) S=H⋅U+N
View Answer

Answer: d
Explanation: The mathematical model of the image degradation in frequency domain representation: S=H⋅U+N, where S is a spectrum of blurred (degraded) image, U is a spectrum of original true (undegraded) image, H is a frequency response of point spread function (PSF), N is a spectrum of additive noise.
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8. Which function is used to calculate the Laplacian of the image?
a) Laplacian()
b) lacian()
c) LaplacianImage()
d) Laplacianimg()
View Answer

Answer: a
Explanation: Laplacian() is used to calculate the Laplacian of the image. The function calculates the Laplacian of the source image by adding up the second x and y derivatives calculated using the Sobel operator.

9. What is the full form of SNR?
a) Sign-to-noise ratio
b) Signal-to-notes ratio
c) Signal-to-noise receiver
d) Signal-to-noise ratio
View Answer

Answer: d
Explanation: The Full form of SNR is Signal-to-noise ratio SNR is a measure independent of the type of noise that you are analyzing, but the significance and usability of the parameter is very dependent of the type of noise.
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10. A line segment is the PSF (point spread function) of which type of motion blur distortion?
a) Bilinear motion blur distortion
b) Linear motion blur distortion
c) Cubic motion blur distortion
d) Quad motion blur distortion
View Answer

Answer: b
Explanation: The point spread function (PSF) of a linear motion blur distortion is a line segment. Such a PSF is specified by two parameters: LEN is the length of the blur and THETA is the angle of motion.

Sanfoundry Global Education & Learning Series – OpenCV.

To practice all areas of OpenCV, here is complete set of Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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