1. Which filtering technique is used to simultaneously enhance contrast and correct non-uniform illumination in an image?
(A) Low-pass filtering
(B) High-pass filtering
(C) Homomorphic filtering
(D) Median filtering
2. What is the key idea behind homomorphic filtering in image processing?
(A) Linear smoothing
(B) Edge detection
(C) Separation of illumination and reflectance
(D) Image compression
3. Which domain is primarily used for homomorphic filtering?
(A) Spatial domain
(B) Frequency domain
(C) Time domain
(D) Pixel domain
4. In homomorphic filtering, which component of the image is considered to carry the fine details and texture?
(A) Illumination
(B) Reflectance
(C) Noise
(D) Histogram
5. What mathematical operation is applied to convert multiplicative components into additive ones in homomorphic filtering?
(A) Differentiation
(B) Fourier Transform
(C) Logarithm
(D) Convolution
6. Which transformation is used after applying the logarithmic function in homomorphic filtering?
(A) Wavelet Transform
(B) Histogram Equalization
(C) Fourier Transform
(D) Edge Detection
7. In the homomorphic filtering process, what happens to the illumination component in the frequency domain?
(A) It is amplified
(B) It is filtered with a high-pass filter
(C) It is enhanced
(D) It is preserved as it is
8. Which of the following is a result of applying homomorphic filtering to an image?
(A) Reduced sharpness
(B) Blurred features
(C) Enhanced details with normalized lighting
(D) Reduced contrast
9. Why is the exponential function used in the final step of homomorphic filtering?
(A) To sharpen edges
(B) To revert the logarithmic transformation
(C) To detect boundaries
(D) To apply Gaussian smoothing
10. What type of filter is typically used in the frequency domain for homomorphic filtering?
(A) Low-pass
(B) High-pass
(C) Band-stop
(D) Mean filter
11. Which type of lighting problem can homomorphic filtering solve?
(A) Motion blur
(B) Non-uniform illumination
(C) Occlusion
(D) Color bleeding
12. What is a major advantage of homomorphic filtering over spatial domain contrast enhancement techniques?
(A) Requires less computation
(B) Simpler algorithm
(C) Handles multiplicative noise effectively
(D) No need for frequency transform
13. What component in an image varies slowly and is responsible for the shading effect?
(A) Reflectance
(B) Edge information
(C) Illumination
(D) Texture
14. Homomorphic filtering is best suited for which type of images?
(A) Binary images
(B) Images with uniform intensity
(C) Images with uneven lighting
(D) Colorized cartoons
15. What is the effect of applying a high-pass filter in the frequency domain during homomorphic filtering?
(A) Smooths the image
(B) Removes noise
(C) Suppresses low-frequency illumination
(D) Amplifies low-frequency components
16. Which step directly follows the logarithmic transformation in homomorphic filtering?
(A) Exponentiation
(B) High-pass filtering
(C) Fourier Transform
(D) Histogram Equalization
17. Which frequency components are associated with image reflectance?
(A) Low-frequency components
(B) High-frequency components
(C) Zero-frequency components
(D) Negative frequency components
18. What is the purpose of taking the log of the image intensity values in homomorphic filtering?
(A) Reduce noise
(B) Convert multiplicative effects to additive
(C) Apply histogram equalization
(D) Normalize the histogram
19. Which of the following is not typically a part of the homomorphic filtering process?
(A) Logarithmic transform
(B) Fourier transform
(C) Histogram matching
(D) High-pass filtering
20. In homomorphic filtering, the exponential function is applied in which domain?
(A) Frequency domain
(B) Spatial domain
(C) Time domain
(D) Gradient domain
21. The illumination component is usually modeled as:
(A) High-frequency
(B) Uniform
(C) Low-frequency
(D) Noise
22. What is typically assumed about the reflectance component in homomorphic filtering?
(A) It is smooth
(B) It is low frequency
(C) It contains high-frequency details
(D) It is independent of illumination
23. Homomorphic filtering is a type of:
(A) Edge detection method
(B) Frequency domain filtering technique
(C) Spatial domain filtering technique
(D) Morphological operation
24. Which of the following combinations best describes the sequence of homomorphic filtering steps?
(A) Log → FFT → High-pass filter → IFFT → Exp
(B) FFT → High-pass filter → Log → IFFT → Exp
(C) Log → High-pass filter → Exp
(D) Exp → FFT → Low-pass filter → Log
25. What role does the inverse FFT play in homomorphic filtering?
(A) Transform image to frequency domain
(B) Suppress illumination
(C) Return image to spatial domain
(D) Apply high-pass filtering
26. The logarithmic transformation helps to:
(A) Enhance image resolution
(B) Sharpen image edges
(C) Convert multiplication into addition
(D) Normalize the histogram
27. Which mathematical property is crucial for homomorphic filtering?
(A) Linearity of convolution
(B) Additivity of log function
(C) Separability of kernel
(D) Commutativity of multiplication
28. Homomorphic filtering uses which type of filtering to enhance reflectance?
(A) Low-pass
(B) High-pass
(C) Band-reject
(D) Gaussian smoothing
29. Why is the homomorphic filter sometimes called a high-frequency emphasis filter?
(A) It uses low-pass components
(B) It emphasizes smooth areas
(C) It boosts high-frequency reflectance
(D) It removes textures
30. What is the final result after applying homomorphic filtering to an image?
(A) Reduced sharpness and contrast
(B) Enhanced illumination
(C) Enhanced contrast and details
(D) Blurred background
31. What kind of filter is typically combined with the homomorphic filter for better control over enhancement?
(A) Gaussian filter
(B) Butterworth filter
(C) Laplacian filter
(D) Median filter
32. Which component is considered undesirable and often suppressed in homomorphic filtering?
(A) Reflectance
(B) Texture
(C) Illumination
(D) Noise
33. Which of the following is not a reason for using homomorphic filtering?
(A) Remove periodic noise
(B) Enhance image contrast
(C) Normalize lighting
(D) Separate reflectance and illumination
34. In homomorphic filtering, what kind of illumination does the filter attempt to suppress?
(A) Uniform
(B) Slowly varying
(C) Random
(D) Impulse-based
35. Which of the following transformations does not occur in homomorphic filtering?
(A) Log
(B) Exponential
(C) Convolution
(D) Fourier
36. What is the reason for applying inverse transform in homomorphic filtering?
(A) Convert spatial domain to frequency
(B) Apply filter in the spatial domain
(C) Bring the image back to spatial domain
(D) Smooth the image
37. Which component is kept while suppressing the illumination in homomorphic filtering?
(A) Low-frequency
(B) Noise
(C) Reflectance
(D) Shading
38. Which type of image is likely to benefit the most from homomorphic filtering?
(A) Uniformly lit portraits
(B) Images taken in bright sunlight
(C) Images with strong shadows and highlights
(D) Black-and-white text documents
39. What kind of image degradation does homomorphic filtering help to correct?
(A) Motion blur
(B) Salt and pepper noise
(C) Uneven illumination
(D) Chromatic aberration
40. What happens to the reflectance after applying a high-pass filter in homomorphic filtering?
(A) It is smoothed
(B) It is suppressed
(C) It is enhanced
(D) It is unchanged
41. Homomorphic filtering applies filtering in which domain?
(A) RGB domain
(B) Frequency domain
(C) Color domain
(D) Gradient domain
42. Which mathematical function is used to revert the log transformation at the end of the filtering process?
(A) Sine
(B) Cosine
(C) Exponential
(D) Tangent
43. In homomorphic filtering, which operation is used to convert the image back to its original scale?
(A) DFT
(B) Exponentiation
(C) Filtering
(D) Normalization
44. What effect does homomorphic filtering have on image dynamic range?
(A) Increases dynamic range
(B) Decreases dynamic range
(C) Has no effect
(D) Randomizes the dynamic range
45. Which component of the image is assumed to be slowly varying and therefore filtered out by high-pass filtering?
(A) Texture
(B) Reflectance
(C) Illumination
(D) Edges
46. Which stage in homomorphic filtering is responsible for separating the illumination from reflectance?
(A) Filtering
(B) Logarithmic transformation
(C) Inverse FFT
(D) Exponentiation
47. What is a key assumption made in homomorphic filtering about the composition of an image?
(A) It is additive
(B) It is multiplicative
(C) It is random
(D) It is nonlinear
48. Which frequency range is typically enhanced in homomorphic filtering to highlight image features?
(A) Low
(B) Zero
(C) High
(D) Band-stop
49. What is the main benefit of applying homomorphic filtering to medical or satellite images?
(A) Smoothing of tissues
(B) Reduction of memory usage
(C) Better contrast and visibility
(D) Enhanced color fidelity
