OpenCV Interview Questions and Answers

Ques 1. What is CUDA?

CUDA is a parallel computing platform developed by Nvidia that is consists of its own GPU for general computing.

Ques 2. How to find threshold in images using OpenCV?

We can find the threshold of an image in OpenCV with the help of cv.threshold function.

Ques 3. What is Scharr Operator?

Scharr() Operator is an operator that is used to detect the second derivatives of an image in horizontal and vertical directions.

Ques 4. Enlist different types of filters available in OpenCV?

The different types of linear and non-linear filter that you can apply to a picture using OpenCV are, BaeColumn filter, Base filter, BaseRow filter, FilterEngine, Bilateral filter, AdaptiveBilateral Filter, Blur, BorderInterpolate, BoxFilter, BuildPyramid, copyMakeBorder, createBoxFilter, createDerivFilter, createGuassionFilter, createLinear filter, createMorphology filter, createSeparableLinear filter, dilate, erode, filter2D, GuassianBlur, getDerivKernels, getKernelType, getStructuringElement, medianBlur, morphologyEx, Laplacian, pyrDown, pyrUp, pyrMeanShiftFiltering, sepFilter2D, Smooth, Sobel, Scharr.

Ques 5. What is computer vision?

It's a Subset of AI. Computer vision is an interdisciplinary scientific field that deals with how computers can be made to gain a high-level understanding of images or videos.

Ques 6. What are machine learning algorithms available in OpenCV?

Normal Bayes ClassifierK-Nearest NeighborsSupport Vector MachinesDecision TreesBoostingGradient Boosted TreesRandom TreesExtremely randomized trees

Ques 7. How many types of image filters in OpenCV?

• Averaging 
• Gaussian Filtering 
• Median Filtering 
• Bilateral Filtering

Ques 8. How many types of video filters are in OpenCV?

Color ConversionThresholdingSmoothingMorphology Gradients CannyEdgeDetectionContoursHistograms

Ques 9. How can we Increase the Quality of an Image in OpenCV?

Image enhancement process is purely dependent on the application where we need to use the enhanced image and the type of degradation in the image. Few solutions from my basic knowledge

– If image contain so much noises, apply filtering operations such as mean/median etc.

– If the image is looking too dark or too bright apply histogram equalization process to improve the contrast.

– If the image is blurred apply sharpening operations in the image.

Ques 10. What Is Image Transform in OpenCV?

An image can be expanded in terms of a discrete set of basis arrays called basis images. Hence, these basis images can be generated by unitary matrices. An NxN image can be viewed as an N^2×1 vectors. It provides a set of coordinates or basis vectors for vector space.

Ques 11. What do you mean by zooming of digital images?

Zooming may be viewed as over sampling. Zooming involves the creation of new pixel locations and the assignment of gray levels to those new locations.

Ques 12. What Is The Need For Transform in OpenCV?

The need for transform is most of the signals or images are time domain signal (ie) signals can be measured with a function of time. This representation is not always best. Any person of the mathematical transformations is applied to the signal or images to obtain further information from that signal. Particularly, for image processing.

Ques 13. List The Hardware Oriented Color Models?

They are as follows.– RGB model– CMY model– YIQ model– HSI model

Ques 14. Do You Know What Rectification Is In Image Processing in OpenCV?

They are as follows.

– Rectification in Image Processing is a transformation process used to project two-or-more images onto a common image plane.

– It corrects image distortion by transforming the image into a standard coordinate system.

– It is used in computer stereo vision to simplify the problem of finding matching points between images.

– It is used in geographic information systems to merge images taken from multiple perspectives into a common map coordinate system.

Ques 15. What Is Meant By Illumination And Reflectance?

Illumination is the amount of source light incident on the scene. It is represented as i(x, y). Whereas, Reflectance is the amount of light reflected by the object on the scene. It is represented by r(x, y).

Ques 16. List The Categories Of Digital Storage in OpenCV?

They are as follows

– Short term storage for use during processing.

– Online storage for relatively fast recall.

– Archival storage for infrequent access.

Ques 17. What Are The Differences Between Structural Patterns & Morphological Structural Element?

In software engineering, structural design patterns are design patterns that ease the design by identifying a simple way to realize relationships between entities.

Ques 18. What Are The Steps Involved In Dip?

They are as follows.

Ques 19. What Is Geometric Transformation?

Transformation is used to alter the co-ordinate description of image.The basic geometric transformations are