BS ISO 17850:2015 BSI Standards Publication Photography — Digital cameras — Geometric distortion (GD) measurements BS ISO 17850:2015 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO 17850:2015. The UK participation in its preparation was entrusted to Technical Committee CPW/42, Photography. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. © The British Standards Institution 2015. Published by BSI Standards Limited 2015 ISBN 978 0 580 82900 0 ICS 37.040.01 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2015. Amendments issued since publication Date Text affected BS ISO 17850:2015 INTERNATIONAL ISO STANDARD 17850 First edition 2015-07-01 Photography — Digital cameras — Geometric distortion (GD) measurements Photographie — Caméras numériques — Mesurages de distorsion géométrique (DG) Reference number ISO 17850:2015(E) © ISO 2015 BS ISO 17850:2015 ISO 17850:2015(E)  COPYRIGHT PROTECTED DOCUMENT © ISO 2015, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form orthe by requester. 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 Ch. de Blandonnet 8 • CP 401 ISOCH-1214 copyright Vernier, office Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 www.iso.org [email protected] ii  © ISO 2015 – All rights reserved BS ISO 17850:2015 ISO 17850:2015(E)  Contents Page Foreword.........................................................................................................................................................................................................................................iv Introduction...................................................................................................................................................................................................................................v 1 Scope.................................................................................................................................................................................................................................. 1 2 Normative references....................................................................................................................................................................................... 1 3 Terms and definitions...................................................................................................................................................................................... 1 4 Measurement methods................................................................................................................................................................................... 2 4.1 General............................................................................................................................................................................................................ 2 4.2 Local geometric distortion............................................................................................................................................................. 3 4.3 Line geometric distortion............................................................................................................................................................... 3 5 Requirements........................................................................................................................................................................................................... 4 5.1 Apparatus and hardware................................................................................................................................................................. 4 5.2 Lighting........................................................................................................................................................................................................... 4 5.3 Dot chart........................................................................................................................................................................................................ 5 5.3.1 Design and characteristics....................................................................................................................................... 5 ................................................................................................................ 6 5.4 Grid chart...................................................................................................................................................................................................... 7 5.3.25.4.1 RequirementDesign and characteristics for the chart .......................................................................................................................................planarity 7 5.5 Image/camera settings..................................................................................................................................................................... 8 5.5.1 General...................................................................................................................................................................................... 8 ............................................................................................................ 8 .............................................................................................................................................. 8 5.5.25.5.4 BasicPositioning settings of andthe camerainfluencing.......................................................................................................................................... factors 8 5.5.35.5.5 SpecificExposure, test white procedures balance, and focus.................................................................................................................. 9 6 Determination of geometric distortion......................................................................................................................................10 6.1 Local geometric distortion..........................................................................................................................................................10 ...................................................................................................................................................10 6.1.2 Outline of the practical algorithm...................................................................................................................10 6.2 Line6.1.1 geometricNumerical distortion definition............................................................................................................................................................11 6.2.1 Horizontal line distortion.......................................................................................................................................11 6.2.2 Vertical line distortion..............................................................................................................................................12 6.2.3 Total line distortion.....................................................................................................................................................12 7 Presentation of results.................................................................................................................................................................................13 7.1 General.........................................................................................................................................................................................................13 7.2 Local geometric distortion..........................................................................................................................................................13 7.3 Line geometric distortion............................................................................................................................................................14 Annex A (informative) Illustrative example and validation.......................................................................................................15 Annex B (informative) Extracting the dots from the target........................................................................................................17 Annex C (informative) Dot centre validation.............................................................................................................................................25 Annex D (informative) Grid sort..............................................................................................................................................................................30 Annex E (informative) Example of subjective evaluation.............................................................................................................40 Bibliography..............................................................................................................................................................................................................................48