ISO/IEC INTERNATIONAL STANDARD 15938-13 First edition 2015-09-01 Information technology Multimedia content description interface - Part 13: Compact descriptors for visual search Technologies de I'information -Interface de description du contenumultimedia- Partie13: Descripteurs compacts pour recherche visuelle Referencenumber IS0/IEC15938-13:2015(E) IEC . Intermational Organization for Standardization rdization5956617 @IS0/IEC2015 IS0/IEC15938-13:2015(E) COPYRIGHTPROTECTEDDOCUMENT IS0/IEC 2015,Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8. CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +4122 749 09 47 copyright@iso.org www.iso.org Intemationaibr PrganizationforStandardization etworking permitted without license from IHS NotforResale, 2015/11/11 09:06:23 IS0/IEC15938-13:2015(E) Contents Page Foreword ..V Introduction.. ..vi 1 Scope. 2 Terms and definitions 3 Symbols and abbreviated terms .2 3.1 General .2 3.2 Abbreviations. 3.3 Arithmeticoperations .3 3.4 Logical operators .3 3.5 Relational operators. 3 3.6 Bitwise operators. .4 3.7 Assignment 4 3.8 Mnemonics .4 3.9 Constants. .4 3.10 Functions. .4 CDVS syntax. .5 4.1 Binary representation syntax .5 4.2 Descriptor component semantics .6 5 CDVS encoding. .9 5.1 General ..9 5.2 Original image preprocessing .9 5.3 Interest point detection. .9 5.3.1 Introduction 9 5.3.2 Scalespaceconstruction 5.3.3 Detection of scale-space extrema ..10 5.3.4 Coordinaterefinementto subpixel precision. .14 5.3.5 Transformation of coordinates and scaleto the converted image resolution 17 5.3.6 Eliminationof duplicates 17 5.3.7 Orientation Assignment. 17 5.3.8 Interest point characteristics .19 5.4 Local feature selection. 19 5.4.1 Operation. .19 5.4.2 Descriptorcomponents 20 5.5 Local feature description .21 5.6 Local feature descriptor aggregation .23 5.6.1 Operation. 23 5.6.2 Descriptor components 26 5.7 Localfeaturedescriptorcompression 27 5.7.1 Operation 27 5.7.2 Descriptor components 30 5.8 Localfeaturelocation compression .31 5.8.1 Operation... .31 5.8.2 Descriptor components .36 5.9 Encoding orderof compressed local feature descriptors and relevancebits. ..37 5.10 Computation of the number of compressed local feature descriptors at different imagedescriptorlengths. .37 AnnexA(informative)CDvSencoderorganization ..38 AnnexB (normative)Coefficientsforcoordinaterefinement .39 AnnexC (normative)Probabilityvaluesforthefeatureselection ..41 Annex D (normative) PCA projection matrixforlocalfeature descriptor aggregation ..44 ntemainal oganzation @SISS/EG2015 -All rights reserved iii icensee=Zhejiang Institute of Standardization5956617 ed without license from IHS Not for Resale, 2015/11/11 09:06:23 No reproduction or networking permi