Enhancing 3D Object Matching with Robust Segmentation Techniques
This paper presents a novel approach to 3D object matching by exploiting segmentation to improve robustness against clutter and occlusion. We introduce advanced shape-based pose quality metrics that do not assume any object texture, along with a gradient-based optimization framework for beam-based sensor models. Key contributions include a new segmentation sensor model that enhances the traditional beam-based models by considering viewpoint and surface extents. Results demonstrate improved performance over traditional methods, with all code and test data made freely available for further research.
Enhancing 3D Object Matching with Robust Segmentation Techniques
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Presentation Transcript
Exploiting Segmentation for Robust 3D Object Matching Michael Krainin, Kurt Konolige, and Dieter Fox
Shape-based Pose Quality Metrics • Given an object model (triangle mesh) and a depth map, • Should not assume any object texture • Should be robust to clutter and occlusion
Outline • Progression of quality metrics • Iterative Closest Point • Beam-based Sensor Models • Segmentation Sensor Model • Key Contributions • Gradient-based optimization for beam-based models • Improves on ICP by reasoning about free-space • Novel sensor model framework • Uses segmentation to relax beam-independence assumptions • Explicitly reasons about surface extents
ICP Error Metric Mean squared distance for pairs of closest points [Besl& McKay‘92] No notion of amount of model or scene explained by the correspondences Discards viewpoint/free-space information
Beam-Based Sensor Models x x x x x p(pixel | model, pose) x x l 0 MeasuredDepth – RenderedDepth Maximize data likelihood: Typically assume pixel independence:
Beam Model Sensor Models • Beam-based sensor model properties: • Consider viewpoint • Prefer to explain more pixels using the model • Use in pose estimation: • 2D particle-based localization [Thrun et al. ‘05] • Coarse to fine grid search for body tracking [Ganapathi et al. ‘10] • Annealed particle filters for vehicle detection and tracking [Petrovskaya & Thrun ‘09] • Has not been used with gradient-based optimization
Beam Model Optimization observed rendered ICP Beam Optimization • We propose a gradient-based optimization • Levenberg-Marquardt using the g2o graph optimization framework [Kümmerle et al. ‘11] • Error function evaluations by re-rendering • OpenGL rendering, CUDA sensor model evaluation • 1 ms per evaluation on a mid-range graphics card • ~500 evaluations per g2o optimization
Surface Extents Can still match to the wrong surface Idea: Use size of surfaces to rule out matches like these
Segmentation (Over-)Segmentation as an estimate of surface extents Connected components using depths and normals
Segmentation Sensor Model Usual beam-based sensor model: Segmentation model: Allows consistent classification of entire segment as being generated from the model or not
Segmentation Sensor Model Let S be a partition (segmentation) of D. Then given model M and pose T, Let mi be an indicator for whether Si was generated from M Segment pixels conditionally independent given classification
Error Functions x Standard Beam-Based Model Segmentation Model
Test Data Recorded 46 cluttered scenes with ground truth poses
Pose Estimation Results Optimization algorithms: Random restart evaluation functions (upper bounded by 93% from previous result):
Robustness to Segmentation Granularity Spam 1 of 5 0 degrees x x x (Fixed to 8 degrees in other experiments) 12 degrees 8 degrees
Conclusions • Contributions • Novel formulation for beam-based sensor models • Demonstration of gradient-based approach for optimizing beam-based sensor models • All code and test data freely available • Future Work • Detecting failed segmentations • Extensions such as color and normal direction • Directly optimizing the segmentation model