1. What is the primary purpose of a smoothing filter in image processing?
(A) Sharpen image edges
(B) Remove high-frequency noise
(C) Enhance contrast
(D) Detect edges
2. Which smoothing filter replaces each pixel value with the average of its neighborhood?
(A) Median filter
(B) Gaussian filter
(C) Mean filter
(D) Laplacian filter
3. Which filter is best suited for removing salt-and-pepper noise?
(A) Mean filter
(B) Gaussian filter
(C) Sobel filter
(D) Median filter
4. What shape is the kernel of a typical Gaussian filter?
(A) Box
(B) Circular
(C) Bell-shaped
(D) Triangular
5. Which filter uses a nonlinear approach to smooth an image?
(A) Mean filter
(B) Gaussian filter
(C) Median filter
(D) Average filter
6. The mean filter is also known as the:
(A) Convolution filter
(B) Moving average filter
(C) Difference filter
(D) Gradient filter
7. What does a larger kernel size in a smoothing filter generally lead to?
(A) More sharpening
(B) Less blurring
(C) More blurring
(D) Edge detection
8. What property of Gaussian filters makes them useful in many image processing tasks?
(A) Nonlinear nature
(B) Directional filtering
(C) Rotational symmetry
(D) Binary thresholding
9. Which filter would you use to preserve edges while reducing noise?
(A) Mean filter
(B) Median filter
(C) Gaussian filter
(D) Laplacian filter
10. What is the primary drawback of using a mean filter?
(A) It introduces new noise
(B) It enhances edges
(C) It blurs edges
(D) It is too fast
11. How does the median filter determine the output pixel value?
(A) Calculates average
(B) Uses Gaussian weighting
(C) Picks middle value
(D) Selects max value
12. Gaussian smoothing is especially effective for which type of noise?
(A) Salt-and-pepper
(B) Gaussian
(C) Impulse
(D) Uniform
13. Which of the following is a linear smoothing filter?
(A) Median filter
(B) Gaussian filter
(C) Bilateral filter
(D) Kuwahara filter
14. Which filter gives equal weight to all neighboring pixels?
(A) Gaussian filter
(B) Mean filter
(C) Median filter
(D) Sobel filter
15. Which filter uses a weighted average where center pixels have more influence?
(A) Laplacian filter
(B) Mean filter
(C) Gaussian filter
(D) Roberts filter
16. What is the effect of applying a smoothing filter multiple times?
(A) Increases noise
(B) Reduces blur
(C) Increases blur
(D) Adds sharpness
17. Which filter is least affected by outliers in the data?
(A) Mean filter
(B) Gaussian filter
(C) Median filter
(D) Prewitt filter
18. In Gaussian filtering, the standard deviation (sigma) controls:
(A) Number of pixels
(B) Edge strength
(C) Spread of the kernel
(D) Filter speed
19. Which filter can cause blocky artifacts if not used carefully?
(A) Median filter
(B) Mean filter
(C) Gaussian filter
(D) Laplacian filter
20. What is the complexity of a median filter in 2D images?
(A) O(1)
(B) O(log n)
(C) O(n)
(D) O(n log n)
21. Which filter is considered a low-pass filter?
(A) Median filter
(B) Gaussian filter
(C) Sobel filter
(D) Laplacian filter
22. What happens to image details when a smoothing filter is applied?
(A) Enhanced
(B) Removed
(C) Distorted
(D) Zoomed
23. What kind of noise is the median filter most effective against?
(A) Gaussian noise
(B) Uniform noise
(C) Salt-and-pepper noise
(D) Speckle noise
24. The mean filter is most effective when the noise is:
(A) Uniform
(B) Impulse
(C) Gaussian
(D) Periodic
25. Which filter is more computationally expensive?
(A) Mean filter
(B) Median filter
(C) Gaussian filter
(D) Box filter
26. What is a common size for a smoothing kernel?
(A) 2×3
(B) 5×1
(C) 3×3
(D) 6×2
27. Gaussian filters are based on which mathematical function?
(A) Sinusoidal
(B) Polynomial
(C) Exponential
(D) Linear
28. Which filter performs well at removing Gaussian noise but may blur edges?
(A) Median filter
(B) Mean filter
(C) Sobel filter
(D) Prewitt filter
29. Which filter performs sorting of pixel values in the kernel window?
(A) Mean filter
(B) Gaussian filter
(C) Median filter
(D) Box filter
30. What is the typical effect of applying a 5×5 median filter to an image?
(A) Edge enhancement
(B) Noise addition
(C) Noise reduction
(D) Histogram equalization
31. Which filter is less sensitive to extreme pixel values?
(A) Gaussian filter
(B) Mean filter
(C) Median filter
(D) Average filter
32. What does a Gaussian filter kernel resemble in a 2D plot?
(A) Pyramid
(B) Sphere
(C) Bell curve
(D) Triangle
33. The main disadvantage of median filters is:
(A) They are fast
(B) They can reduce image contrast
(C) They increase noise
(D) They are nonlinear and slow
34. What is preserved better by a median filter compared to a mean filter?
(A) Texture
(B) Edges
(C) Brightness
(D) Sharpness
35. Which of the following is a spatial domain filtering technique?
(A) Fourier Transform
(B) Median filtering
(C) Histogram equalization
(D) Wavelet Transform
36. A 3×3 Gaussian kernel is used to:
(A) Detect edges
(B) Reduce color
(C) Blur the image
(D) Increase resolution
37. Smoothing filters reduce:
(A) High-frequency components
(B) Low-frequency components
(C) Both equally
(D) None of them
38. Which of the following filters is isotropic?
(A) Mean filter
(B) Gaussian filter
(C) Sobel filter
(D) Prewitt filter
39. Which filter is most robust in preserving small image details?
(A) Gaussian filter
(B) Mean filter
(C) Median filter
(D) Low-pass filter
40. What does the term “kernel” refer to in smoothing filters?
(A) A pixel
(B) A mask or matrix
(C) A histogram
(D) A frequency component
41. Increasing the size of a Gaussian kernel results in:
(A) More edge detection
(B) Less smoothing
(C) More smoothing
(D) Pixel duplication
42. Which of the following is a major disadvantage of mean filtering?
(A) Computational speed
(B) Blurring of sharp features
(C) Poor denoising
(D) High memory use
43. What does the term “spatial filter” refer to?
(A) A frequency domain process
(B) Time-based operation
(C) A mask applied over pixels
(D) Motion blur
44. Which filter performs averaging using a Gaussian distribution?
(A) Laplacian filter
(B) Mean filter
(C) Gaussian filter
(D) Average filter
45. What effect does smoothing have on image sharpness?
(A) Increases sharpness
(B) Removes color
(C) Reduces sharpness
(D) No effect
46. In image processing, the term “denoising” means:
(A) Adding texture
(B) Enhancing frequency
(C) Removing noise
(D) Scaling image size
47. Which filter maintains overall brightness better?
(A) Mean filter
(B) Gaussian filter
(C) Median filter
(D) Bilateral filter
48. Why are Gaussian filters preferred in image preprocessing?
(A) They’re nonlinear
(B) Fast Fourier Transform is used
(C) They reduce noise and preserve structure
(D) They binarize the image
49. Which smoothing filter is based on statistical ranking?
(A) Mean filter
(B) Median filter
(C) Gaussian filter
(D) Box filter
50. The standard deviation in a Gaussian filter affects:
(A) Filter shape
(B) Output image size
(C) Memory allocation
(D) Image contrast
