Combining Visual in addition to Spatial Appearance as long as Loop Closure Detection in SLAM Motivation Image Loop Closure Closing the loop

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Combining Visual in addition to Spatial Appearance as long as Loop Closure Detection in SLAM Motivation Image Loop Closure Closing the loop

Nagel, Jason, On-Air Talent has reference to this Academic Journal, PHwiki organized this Journal Combining Visual in addition to Spatial Appearance as long as Loop Closure Detection in SLAM Kin Leong Ho, Paul Newman Ox as long as d University Robotics Research Group Motivation Loop Closing – the task of deciding whether a vehicle has returned to a previously visited area Popular approaches – nearest neighbour statistical gate, joint compatibility test Image Loop Closure Closing loops with visually salient features to avoid dependence on global position estimate

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Closing the loop MSER detector Saliency detector Image Feature Extraction Process Demonstration of wide-baseline stability of visually salient features under perspective distortion in addition to variation in illumination conditions

Matching Per as long as mance Similar posters found in the environment. [Newman,Ho ICRA2005] Query Image Tentative Match Tentative Match Tentative Match Results from Image Retrieval System Limitations of Image Matching – Repetitive visual artifacts in urban environments such as posters, signs in addition to wall pattern False triggering of loop closure event based solely on image matching Query Image Tentative Match Tentative Match

Incorporating Spatial In as long as mation Spatial in as long as mation can be used to disambiguate visually confusing locations Spatial Descriptors Reduced a laser scan patch into a set of descriptor Describe curvature of shape Describe complexity of shape Describe spatial configuration of laser scan Segmentation Laser scan is divided into smaller but sizeable segments Segments are as long as med due to break in boundary or occlusions Original Laser Scan Set of Descriptors

Cumulative Angular Function A plot of the cumulative change in turning angle versus the arc length of the segment Invariant to rotation in addition to translation Arc length of Segment Turning Angle Entropy of CAF A measure of complexity of segment Weight descriptors to prefer between complex versus simple shapes CAF Histogram of Turning Angle Inter-Segment Descriptors Extract critical points: Critical points are points along a segment where there are sharp changes in cumulative angular function Distances in addition to relative orientations between critical points as long as m links between segments

Descriptor Comparison 1 Angular function disparity – minimum error between two cumulative angular functions Descriptor Comparison 2 entropy disparity – Kullback-Leiber distance Edge Comparison Matching of links Links that are matched are coloured in black Links that are not matched are coloured in blue

Spatial Similarity Score Shape similarity metric comprises of two parts: shape similarity in addition to spatial similarity Results from Spatial Retrieval System More Results

Query Image MSER Detector Saliency Detector Selected Regions SIFT Descriptor Image Database Similarity Measure Laser Descriptor Laser Scan Database Similarity Measure Combined Similarity Scores Segmentation Query Laser Scan Visual Similarity Matrix Spatial Similarity Matrix

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Combined Similarity Matrix Demonstration Issues Setting of threshold values Principled way of combining similarity scores At present limited to planar environments Current Extensions Removal of repetitive images by spectral decomposition Successful Application to 3D laser mapping in addition to SLAM

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Nagel, Jason is from United States and they belong to KWMT-FM and they are from  Tucson, United States got related to this Particular Journal. and Nagel, Jason deal with the subjects like Music

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