OpenCV Questions and Answers – Cartoon – Set 3

This set of OpenCV Multiple Choice Questions & Answers (MCQs) focuses on “Cartoon – Set 3”.

1. Which enumerator gives enable/ disable auto white-balance?
a) CAP_PROP_AUTO_WB
b) CAP_PROP_WB_TEMPERATURE
c) CAP_PROP_EXPOSURE
d) CAP_PROP_SATURATION
View Answer

Answer: a
Explanation: CAP_PROP_AUTO_WB is the enumerator that gives enable/ disable auto white-balance, while CAP_PROP_WB_TEMPERATURE enumerator gives white-balance color temperature.

2. Which enumerator gives exposure control done by camera; user can adjust reference level using this feature?
a) CAP_PROP_AUTO_EXPOSURE
b) CAP_AUTO_EXPOSURE
c) CAP_PROP_EXPOSURE
d) CAP_PROP_AUTO
View Answer

Answer: a
Explanation: CAP_PROP_AUTO_EXPOSURE is the enumerator that gives exposure control done by camera, user can adjust reference level using this feature, while CAP_PROP_EXPOSURE enumerator gives Exposure (only for those cameras that support).

3. Which enumerator gives Saturation of the image (only for cameras)?
a) CAP_PROP_HUE
b) CAP_PROP_GAIN
c) CAP_PROP_EXPOSURE
d) CAP_PROP_SATURATION
View Answer

Answer: d
Explanation: CAP_PROP_SATURATION is the enumerator that gives Saturation of the image (only for cameras) while CAP_PROP_EXPOSURE enumerator gives Exposure (only for those cameras that support).
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4. Which enumerator gives Rectification flag for stereo cameras?
a) CAP_PROP_MODE
b) CAP_PROP_RECTIFICATION
c) CAP_PROP_EXPOSURE
d) CAP_PROP_RECTIFY
View Answer

Answer: b
Explanation: CAP_PROP_RECTIFICATION is the enumerator that gives Rectification flag for stereo cameras (only supported by DC1394 v 2.x backend currently) while CAP_PROP_MODE is the enumerator that gives Backend-specific value indicating the current capture mode.

5. Which enumerator gives Boolean flags indicating whether images should be converted to RGB?
a) CAP_PROP_CONVERT_RGB
b) CAP_PROP_GAIN
c) CAP_PROP_CONVERT
d) CAP_PROP_EXPOSURE
View Answer

Answer: a
Explanation: CAP_PROP_CONVERT_RGB is the enumerator that gives Boolean flags indicating whether images should be converted to RGB while CAP_PROP_EXPOSURE enumerator gives Exposure (only for those cameras that support).

6. Which enumerator gives Width of the frames in the video stream?
a) CAP_PROP_CONVERT_RGB
b) CAP_PROP_FRAME_WIDTH
c) CAP_PROP_WIDTH
d) CAP_PROP_FRAME_HEIGHT
View Answer

Answer: b
Explanation: CAP_PROP_FRAME_WIDTH is the enumerator that gives Width of the frames in the video stream, while CAP_PROP_CONVERT_RGB is the enumerator that gives Boolean flags indicating whether images should be converted to RGB.

7. Which enumerator gives 4-character code of codec?
a) CAP_PROP_CONVERT_RGB
b) CAP_PROP_4CC
c) CAP_PROP_FOURCC
d) CAP_PROP_EXPOSURE
View Answer

Answer: c
Explanation: CAP_PROP_FOURCC is the enumerator that gives 4(FOUR)-character code of codec while CAP_PROP_EXPOSURE enumerator gives Exposure (only for those cameras that support).
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8. Which enumerator gives Boolean flags indicating whether images should be converted to RGB?
a) CAP_PROP_CONVERT_RGB
b) CAP_PROP_GAIN
c) CAP_PROP_CONVERT
d) CAP_PROP_EXPOSURE
View Answer

Answer: a
Explanation: CAP_PROP_CONVERT_RGB is the enumerator that gives Boolean flags indicating whether images should be converted to RGB while CAP_PROP_EXPOSURE enumerator gives Exposure (only for those cameras that support).

9. Which OpenCV function Creates a trackbar and attaches it to the specified window?
a) createTrackbar()
b) Trackbar()
c) createTrack()
d) createbar()
View Answer

Answer: a
Explanation: createTrackbar() is the OpenCV function that Creates a trackbar and attaches it to the specified window . The function create Trackbar creates a trackbar (a slider or range control) with the specified name and range, assigns a variable value to be a position synchronized with the trackbar and specifies the callback function on Change to be called on the trackbar position change.
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10. Which OpenCV function Destroys all of the High GUI windows?
a) createTrackbar()
b) destroyAllWindows()
c) destroyWindows()
d) destroyWindow()
View Answer

Answer: b
Explanation: destroyAllWindows() is the OpenCV function that Destroys all of the HighGUI (Graphics User Interface) windows while, the OpenCV function destroyWindow destroys the window with the given name.

11. The function getWindowImageRect() returns the client screen coordinates, width and height of the image rendering area.
a) TRUE
b) FALSE
View Answer

Answer: a
Explanation: getWindowImageRect() function Provides rectangle of image in the window. The function getWindowImageRect() returns the client screen coordinates, width and height of the image rendering area.

12. The function namedWindow() creates a window that can be used as a placeholder for images and trackbars.
a) TRUE
b) FALSE
View Answer

Answer: a
Explanation: The function namedWindow() creates a window that can be used as a placeholder for images and trackbars. Created windows are referred to by their names. If a window with the same name already exists, the function does nothing.

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 - Founder & CTO at Sanfoundry
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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