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Realtime Object Recognition Using Decision Tree Learning. Implemented with a Sony AIBO Robot CS 510 Presentation Chris Jorgensen. Realtime Object Recognition Using Decision Tree Learning. Implemented with a Sony AIBO Robot CS 510 Presentation Chris Jorgensen. Presentation.
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Realtime Object Recognition Using Decision Tree Learning Implemented with a Sony AIBO Robot CS 510 Presentation Chris Jorgensen
Realtime Object Recognition Using Decision Tree Learning Implemented with a Sony AIBO Robot CS 510 Presentation Chris Jorgensen
Presentation • Abstract/Introduction • Problem setup • Use of decision tree learning • Results • Summary/Thoughts
Abstract/Introduction • Object recognition • Machine learning used to overcome issues: • Domain-specific • Complexity inestimable • Quality of results • Steps • Digital image scanned for features • Combine features into “meaningful” attributes • Attribute classification
Introduction Continued… Object Recognition Flow
Preprocessing • “Obvious” features • Colors • Limbs/Head • Shapes derived from image • Used for featureextraction
Problem Setup • Recognition • Iterate through surfaces • Head, Side, Leg • Generate segments for each surface • Store segments in memory • 180 degree memory takes into account camera angle
Problem Setup Continued • Segmentation only done on “relevant” pixels • Determined by color • Attribute generation* • Color, # segments, # corners, et al • Continuous values discretization via brute-force generated optimal split
Use of Decision Tree Learning • Classification via Decision Tree Learning! • Algorithm creates a tree consisting of the attributes; leafs are “symbols” • head, side, leg, body, et al • Tree is built by calculating attribute with the highest entropy (depends on # occurrences of each value) • Over-fitting solved by X2-pruning • Determine if attribute really detects a pattern
Results Continued • Decision Tree Learning • Classification (27 ms) “quite fast” • 84% precision on 1080 examples for 5 classes • Even a low number of examples (25) resulted in over 50% precision • Room for improvement noted
Summary/Thoughts • Short/vague paper • Why do they need faster than 27 ms recognition time? Aibos are slow! • Other work on Aibos done at PSU NWCIL • Lendaris/Holmstrom • Aibo uses limb angles, model of motion, to change gait based on floor surface • GA used to generate ideal gait for each surface