WorksheetsCV_6
Total questions: 100
Worksheet time: 50mins
Increasing sensor size while keeping resolution constant mainly improves
Spatial resolution
Signal-to-noise ratio
Quantization levels
Sampling rate
A camera produces blur even for static scenes mainly due to
Low quantization
Long exposure time
Aliasing
Histogram equalization
Brightness constancy assumption is violated when there is
Object rotation
Uniform illumination
Sudden lighting change
Camera translation
If sampling frequency is doubled, Nyquist frequency
Halves
Doubles
Becomes zero
Remains same
Which affects image depth but not spatial resolution?
Sampling
Quantization
Filtering
Scaling
Improving local contrast without affecting global brightness is achieved by
Histogram equalization
Adaptive histogram equalization
Mean filtering
Log transformation
A filter that removes noise but destroys thin lines is likely
Median filter
Gaussian filter
High-pass filter
Laplacian filter
Best noise reduction while preserving edges is achieved using
Mean filter
Median filter
Ideal LPF
Box filter
Negative image transformation is useful for
Edge detection
Highlighting dark details
Noise removal
Compression
Laplacian sharpening amplifies noise because it
Uses first derivative
Works in frequency domain
Emphasizes high frequencies
Reduces contrast
Sharp cutoffs in frequency filters cause
Blur
Ringing artifacts
Quantization
Thresholding
Gaussian filters are preferred since they
Are ideal
Have infinite support
Avoid ringing
Remove edges
Low-pass filtering corresponds to
Differentiation
Integration
Smoothing
Sharpening
Periodic noise removal requires eliminating
DC component
High frequencies
Specific frequency spikes
Spatial outliers
Transform giving both spatial and frequency localization
Fourier
DCT
Wavelet
PCA
Edge detection relies on detecting
Similarity
Discontinuity
Texture
Color
Sobel performs better than Roberts in noise because it
Uses smaller mask
Includes smoothing
Uses second derivative
Works in frequency domain
Histogram-based thresholding assumes
Uniform noise
Bimodal distribution
High resolution
Uniform illumination
Region growing fails mainly due to
Sharp edges
Noise causing false similarity
Strong gradients
Over-filtering
Boundary detection is essential for
Compression
Shape analysis
Noise removal
Sampling
Corners are generally invariant to
Noise
Rotation
Scale
Illumination
Harris corner detection uses
Histogram
Eigenvalues of structure tensor
Hough voting
PCA
Hough Transform complexity increases with
Image size
Parameter space dimensionality
Noise reduction
Thresholding
Feature matching degrades mainly due to
Translation
Viewpoint change
Identical features
High contrast
PCA is unsuitable for
Dimensionality reduction
Feature decorrelation
Non-linear manifolds
Speed of Viola–Jones is due to
CNNs
Integral images
PCA
Optical flow
YOLO formulates detection as
Classification
Segmentation
Regression
Clustering
False positives increase due to
High resolution
Background clutter
Preprocessing
Normalization
Deep learning generalizes poorly when
Data is diverse
Training data is limited
Features are learned
GPU is used
GMM models background using
Uniform distribution
Gaussian mixtures
Binary values
Deterministic values
Optical flow fails when
Texture exists
Motion is slow
Brightness changes
Camera is static
Aperture problem occurs due to
Large motion
Small observation window
Noise
Low resolution
Stereo correspondence matches
Pixels across frames
Pixels across cameras
Objects across scenes
Features across scales
Increasing stereo baseline improves
Matching speed
Depth accuracy
Image quality
Noise suppression
Motion estimation improves with
Large window always
Multi-scale analysis
High noise
Uniform regions
Gaussian blur before Canny is used to
Increase edges
Reduce noise
Improve contrast
Increase resolution
Face recognition fails mainly due to
High resolution
Pose and illumination changes
Noise removal
Edge detection
OCR preprocessing includes
Thresholding & normalization
Feature matching
Stereo vision
Optical flow
Real-time video analytics prioritizes
Accuracy only
Speed–accuracy trade-off
Memory only
Storage
Background subtraction fails when
Camera is fixed
Lighting varies rapidly
Histogram equalization is avoided in medical images because it
Increases contrast
Distorts diagnostic information
Is slow
Reduces resolution
CNNs remove the need for
Training
Manual feature design
Large datasets
GPUs
Multi-scale processing is required because
Objects vary in size
Images are noisy
Quantization is low
Sampling is fixed
Feature normalization improves
Noise
Matching robustness
Edge strength
Segmentation
Tracking fails mainly due to
Object motion
Occlusion
High frame rate
Static background
Grayscale images are used mainly to
Remove information
Reduce computation
Increase noise
Improve color
Edge-based segmentation fails when
Edges are strong
Edges are weak or noisy
Objects are separated
Contrast is high
Deep learning needs large datasets because
Models are shallow
High number of parameters
Low computation
Simple features
Optical flow is expensive because it involves
Pixel-wise motion estimation
Enhancement
Histogram calculation
Thresholding
A complete computer vision pipeline ends with
Enhancement
Segmentation
Recognition
Sampling
A satellite image shows blocky artifacts when zoomed in. The most likely cause is
Noise
Low spatial sampling
High quantization
Histogram equalization
A night-vision camera produces grainy images despite high resolution. The issue is mainly due to
Quantization
Low signal-to-noise ratio
Aliasing
Over-sampling
Two cameras capture the same scene; one image looks darker though resolution is same. The difference is due to
Sampling
Illumination and sensor response
Quantization
Filtering
Medical images require subtle intensity differences to be preserved. Which should be maximized?
Sampling
Quantization levels
Filtering
Compression
A drone image shows distorted object sizes at edges. This is caused by
Noise
Perspective projection
Thresholding
Quantization
A foggy road image needs visibility improvement without amplifying noise. Best method is
Histogram equalization
Contrast stretching
Laplacian sharpening
Thresholding
CCTV footage contains salt-and-pepper noise. The best filter is
Mean
Gaussian
Median
High-pass
After smoothing, fine cracks in a material image disappear. The cause is
Under-sampling
Over-smoothing
Quantization
Aliasing
An image looks washed out after enhancement. The incorrect step is
Normalization
Over-equalization
Smoothing
Conversion to grayscale
Dark objects in X-ray images need emphasis. Suitable transform is
Linear
Logarithmic
Negative
Threshold
Sharp ringing appears after filtering an image. The filter used was likely
Gaussian
Butterworth
Ideal filter
Median
Removing repeating stripes in scanned documents requires
Low-pass filter
High-pass filter
Notch filter
Mean filter
An engineer chooses frequency-domain filtering because
It is local
It handles global patterns efficiently
It removes all noise
It avoids transforms
Excessive high-pass filtering results in
Smoothing
Noise amplification
Contrast loss
Segmentation
A filter with smooth transition avoids ringing because it
Removes DC component
Reduces abrupt frequency changes
Works spatially
Uses median
A road image under shadows fails thresholding. The reason is
Noise
Non-uniform illumination
High contrast
Over-sampling
Broken lane markings are detected as separate edges. Which step is missing?
Smoothing
Thresholding
Edge linking
PCA
Region growing merges background with object due to
Strong edges
Incorrect similarity criteria
High resolution
Sharpening
Watershed segmentation produces too many regions because of
Blur
Over-segmentation
Low resolution
Histogram equalization
For detecting object boundaries in noisy images, best approach is
Thresholding
Canny edge detection
Region growing
PCA
A corner detector fails when object size changes. The detector lacks
Rotation invariance
Scale invariance
Translation invariance
Noise resistance
Harris detector identifies points where
Intensity is maximum
Gradient changes in all directions
Edges are strongest
Histogram peaks
A line is detected even when broken. The algorithm used is
Sobel
Canny
Hough Transform
PCA
Feature matching fails under illumination change because
Features are local
Intensity values vary
Edges disappear
Sampling changes
PCA fails when applied to highly nonlinear image data because it
Is slow
Is a linear technique
Removes noise
Needs labels
Face detection works fast but only for frontal faces. Algorithm used is
CNN
Viola-Jones
YOLO
SIFT
A real-time system detects multiple objects in one pass. The model used is
R-CNN
Fast R-CNN
YOLO
Viola-Jones
Background subtraction fails when lights switch ON/OFF because
Motion stops
Background model becomes invalid
Objects disappear
Frame rate increases
Deep learning detector performs poorly on new environments due to
Over-sampling
Overfitting
PCA
Edge detection
GMM adapts to slow background changes because it
Is static
Updates probability distributions
Uses edges
Uses thresholding
Optical flow fails on a blank wall because of
Noise
Lack of texture
High resolution
Frame rate
An object moves perpendicular to its edge but motion is undetected due to
Noise
Aperture problem
Blur
Quantization
A face detector works only for upright frontal faces but runs very fast. Algorithm used is
CNN
YOLO
Viola-Jones
SIFT
A detector identifies all objects in one forward pass. This indicates use of
Sliding window
R-CNN
YOLO
Hough Transform
Background subtraction fails when sunlight intensity changes suddenly because
Objects stop moving
Background model becomes outdated
Noise increases
Frame rate drops
A deep learning model performs well on training data but poorly on test data due to
Underfitting
Overfitting
Quantization
Sampling
GMM adapts background by
Fixed thresholds
Updating Gaussian parameters
Edge detection
PCA
Optical flow fails on a plain white wall because
Noise
Lack of texture
High resolution
High frame rate
Motion is detected incorrectly along edges due to
Blur
Aperture problem
Noise
Quantization
Stereo vision estimates depth using
Motion
Disparity between views
Histogram
PCA
Increasing baseline improves depth accuracy but also
Reduces noise
Increases correspondence difficulty
Improves illumination
Reduces computation
Motion blur mainly reduces accuracy of
Segmentation
Optical flow
Sampling
Quantization
Converting images to grayscale before processing mainly helps to
Improve color
Reduce computational load
Increase noise
Enhance texture
OCR struggles with cursive handwriting because of
High resolution
Large shape variability
Good contrast
Edge clarity
Facial expression recognition requires analysis of
Color only
Texture and facial muscle movement
Histogram only
Thresholding
Real-time vision systems balance speed and accuracy due to
Storage limits
Computational constraints
Noise
Sampling
Object tracking fails when two objects cross paths due to
Blur
Identity ambiguity
Noise
Resolution
Preprocessing is essential before segmentation because it
Adds features
Improves segmentation reliability
Reduces image size
Performs classification
CNNs outperform handcrafted features because they
Use PCA
Learn hierarchical representations
Avoid training
Use thresholding
Multi-scale processing is required because
Images are noisy
Objects appear at different sizes
Sampling varies
Quantization changes
