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dc.contributor.authorHANSARD, Men_US
dc.contributor.authorHoraud, Ren_US
dc.contributor.authorAmat, Men_US
dc.contributor.authorEvangelidis, Gen_US
dc.date.accessioned2015-08-04T09:31:42Z
dc.date.issued2014-04-01en_US
dc.identifier.urihttp://qmro.qmul.ac.uk/xmlui/handle/123456789/8087
dc.description.abstractIt is convenient to calibrate time-of-flight cameras by established methods, using images of a chequerboard pattern. The low resolution of the amplitude image, however, makes it difficult to detect the board reliably. Heuristic detection methods, based on connected image-components, perform very poorly on this data. An alternative, geometrically-principled method is introduced here, based on the Hough transform. The projection of a chequerboard is represented by two pencils of lines, which are identified as oriented clusters in the gradient-data of the image. A projective Hough transform is applied to each of the two clusters, in axis-aligned coordinates. The range of each transform is properly bounded, because the corresponding gradient vectors are approximately parallel. Each of the two transforms contains a series of collinear peaks; one for every line in the given pencil. This pattern is easily detected, by sweeping a dual line through the transform. The proposed Hough-based method is compared to the standard OpenCV detection routine, by application to several hundred time-of-flight images. It is shown that the new method detects significantly more calibration boards, over a greater variety of poses, without any overall loss of accuracy. This conclusion is based on an analysis of both geometric and photometric error.en_US
dc.format.extent108 - 118en_US
dc.relation.ispartofComputer Vision and Image Understandingen_US
dc.rights© 2014 Elsevier Inc. All rights reserved.
dc.titleAutomatic detection of calibration grids in time-of-flight imagesen_US
dc.typeArticle
dc.rights.holderhttps://doi.org/10.1016/j.cviu.2014.01.007
dc.identifier.doi10.1016/j.cviu.2014.01.007en_US
pubs.author-urlhttp://www.eecs.qmul.ac.uk/~milesh/en_US
pubs.notesNot knownen_US
pubs.organisational-group/Queen Mary University of London
pubs.organisational-group/Queen Mary University of London/Faculty of Science & Engineering
pubs.organisational-group/Queen Mary University of London/Faculty of Science & Engineering/Electronic Engineering and Computer Science - Staff
pubs.volume121en_US


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