Answer: 1 Explanation: The main steps used in Canny Edge Detector are Noise Reduction, Finding Intensity Gradient, Non-max Suppression, Hysteresis Thresholding. Refer to this link to know more.
Q2. Which of the following filter assigns more weights to the nearest pixels as compared to the distant pixels?
Gaussian Filter
Box Filter
Median Filter
All of the above
Answer: 1 Explanation: A Gaussian filter assigns more weights to the nearest pixels as compared to the distant pixels. To know more about Gaussian filter, refer to this link.
Q3. How many thresholds are used in hysteresis thresholding in Canny Edge Detector?
2
1
3
4
Answer: 1 Explanation: To solve the problem of “which edges are really edges and which are not” Canny uses the Hysteresis thresholding. In this, we set two thresholds ‘High’ and ‘Low’. Refer to this link to know more.
Q4. In Bilinear Interpolation, how many neighboring pixels are considered for calculating the intensity value for a new location?
3
1
2
4
Answer: 4 Explanation: Bi-linear interpolation means applying a linear interpolation in two directions. Thus, it uses 4 nearest neighbors for calculating the intensity value for a new location. To know more about Bilinear Interpolation, refer to this link.
Q5. Which of the following image sharpening techniques to use if the image contains a high degree of noise?
Sobel
Laplacian
Difference of Gaussian
Scharr
Answer: 3 Explanation: Because in Difference of Gaussian we are actually doing blurring which reduces the effect of noise to a great extent.
Q6. What response does a second order derivative filter will give along the ramps?
Zero
positive
negative
Answer: 1 Explanation: Because ramps has constant slope so for ramp edge the first order derivates gives constant response along the ramp while second order gives 0 response along the ramp.
Q7. Which of the following OpenCV functions can be used to perform Hit-or-Miss Transform?
Answer: 1 Explanation: In OpenCV, cv2.morphologyEx(img, cv2.MORPH_HITMISS, kernel) can be used to perform Hit-or-Miss Transform. Refer to this link to know more.
Q8. Which of the following Morphological operations closes the holes/gaps present in the object while keeping the initial object size same?
Dilation
Erosion
Closing
Opening
Answer: 3 Explanation: As clear from the name, Dilation dilates or expands the object region so for bridging/closing the holes Dilation can be used but to keep the initial object size same we need Erosion. Since Closing is Dilation followed by Erosion so this can also be used.