andy
5a94c5ff1a
Affected files: STEM/AI/Kalman Filter.md STEM/Signal Proc/Convolution.md STEM/Signal Proc/Image/Tracking.md STEM/Signal Proc/Pole-Zero.md STEM/Signal Proc/Transfer Function.md STEM/Speech/Linguistics/Consonants.md STEM/Speech/Linguistics/Linguistics.md STEM/Speech/Linguistics/README.md STEM/Speech/Linguistics/Terms.md STEM/Speech/Linguistics/Vowels.md STEM/Speech/NLP/Jargon.md STEM/Speech/NLP/NLP.md STEM/Speech/NLP/README.md STEM/Speech/NLP/Recognition.md STEM/Speech/Perception/Perception.md STEM/Speech/Perception/README.md STEM/Speech/Speech Processing/Applications.md STEM/Speech/Speech Processing/README.md STEM/Speech/Speech Processing/Source-Filter.md STEM/Speech/Speech Processing/Vocal Tract.md STEM/img/english-phoneme-table.png STEM/img/formant.png STEM/img/pole-zero-attenuation.png STEM/img/pole-zero-feedback.png STEM/img/pole-zero-stable.png STEM/img/roc-right-left.png STEM/img/roc-two-sided.png STEM/img/spectrum-vocal-tract.png STEM/img/transfer-stable-unstable.png STEM/img/vowel-chart.png STEM/img/vowel-spaces.png
42 lines
1.2 KiB
Markdown
42 lines
1.2 KiB
Markdown
# Challenges
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- Clutter
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- Distractors
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- Occlusion
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- Hidden by other objects
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- Objects appearance can evolve
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- Rotation, scale, camera viewpoint
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- Take new template every n frames
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- Take new template when confidence falls below threshold
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# Background Tracking
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- Static camera
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- Capture clean shots of background
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- Object present
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- Average enough footage
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- Background image - current video frame = difference image
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- Threshold for binary mask
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# Nearest Neighbour Tracking
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- Decide component with closest centroid using previous centroid
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- Not good for occlusion
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- Will snap to next candidate
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# Blob Tracking
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- Build colour model of object
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- Eigenmodel
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- Mask of pixels that match object
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- Use centroid as location over time
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- Pick connected component with centroid closest to previous location
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- Good for distinctive colours
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- Not for practical situations though
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# Template Tracking
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- Sample distinctive patch from image
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- Search all positions in video for patch
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- Use cross-correlation
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- Illumination changes
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- Brightness is uniform shift of greyscale values up or down
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- Correlated to the mean pixel value
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- Subtract means in template and frame to give invariance
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- Normalised cross-correlation |