Object Recognition

Explore object recognition techniques in this guest presentation by Dr. Arnold Smeulders. Delve into Bag of Words models, patch sampling methods, and dictionary formation for image classification. Learn about concept-specific codebooks, soft word assignment, and Fisher vectors. Examine visual synonyms and convex reduced codebooks. Investigate the importance of object location, context, and hierarchical search methods like selective search. Understand the interplay between object classification and localization in computer vision tasks.

Object recognition
Bag of Words
Bags of Words
Capture the pattern in patch
The dimensionality
Sample many patches
Two types of sampling
Sample many images
Include all relevant variations
Form a dictionary of words
Ideally words cover similar patches
Count words per image
Codeboods
Learn histogram similarity
Similarity between two histograms
Classify unknown image
Concept-specific codebooks
Conclusion on concept-codebooks
Soft word assignment
Fisher vector
Conclusion on words
Codebook synonyms
How close are synonyms?
90% removed, same result
Visual synonym examples
Conclusion on visual synonyms
Convex reduced codebooks
Conclusion convex reduced
The where and what
What makes a boat a boat?
What is the object in the middle?
Where is evidence?
Where is evidence for an object?
The visual extent of an object
Context dominance
Object dominance
Object detail dominance
Pyramids: simple compositional
Exhaustive search
The need for high recall
The need for hierarchy
Selective search example
Selective search to get high recall
Average best overlap -88%
Classification with selective search
Conclusion on location
Two concepts in interaction