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Explore a novel representation for dense visual SLAM using code learning, enabling efficient reconstruction of high-frequency details. This alternative to depth maps is beneficial in SfM or SLAM scenarios, with an architecture that includes color feature extraction and uncertainty prediction. Learn about the benefits of variational autoencoders and small code changes for depth reconstruction accuracy.
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Vision Reading Group, 2nd of May 2018 Martin Rünz CodeSLAM — Learning a Compact, Optimisable Representation for Dense Visual SLAM
In a nutshell An alternative representation to depth maps is presented
Background – Common Map Representations Surfels Mesh Pose-Graph + Depth-Maps TSDF
Ideas • Depth-maps are notrandom
Ideas • Depth-maps are notrandom(especially in man-made environments)
Ideas • Depth-maps are notrandom • A compact representation – code – can be learned by encoder • Decoders are differentiable → code can be optimised (w.r.t. photometric loss...) • This is useful in SfM or SLAM scenarios • Reconstruct high-frequency details from color
Depth Reconstruction • Depth-from-mono • Depth-from-mono + code • Given this differentiable function, warping constraints can be used to optimise c and pose
Architecture Color feature extractor + uncertainty predictor Laplace distribution Only for training, ground-truth depth • Variational autoencoder, to increase smoothness of mapping between code and depth • Small changes in code → small changes in depth Decoder: CODE
Inverse depth parametrization average • Error behaves moreGaussian original depth
Warping Transform → B 3D Photometric error: • Both functions differentiable to inputs Expensive(convolutions) Pre-computed if decoder is linear!
Application • SfM • Initialise poses and code with zero-vector • Use residuals + Jacobians in Gauss-Newton style optimisation • Cost function: • Functionality of : • Mask invalid correspondences • Relative weighting • Huber weighting • Down-weight slanted surfaces • Down-weight occluded pixels
Experiments • SfM
Experiments • SfM
Experiments • SLAM
Experiments • Setups
Experiments • Setups
Experiments • Influence code entries