ISO INTERNATIONAL STANDARD 17850 First edition 2015-07-01 Photography Digital cameras - Geometric distortion (GD) measurements Photographie - Cameras numeriques - Mesurages de distorsion géométrique (DG) Reference number IS0 17850:2015(E) ISO IS02015 IS0 17850:2015(E) COPYRIGHT PROTECTED DOCUMENT @ IS0 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 +41 22 749 09 47 copyright@iso.org www.iso.org @ IS0 2015 - All rights reserved IS0 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 5.3.2 Requirement for the chart planarity 6 5.4 Grid chart 7 5.4.1 Design and characteristics. 7 5.5 Image/camera settings. .8 5.5.1 General. .8 5.5.2 Basic settings and influencing factors .8 5.5.3 Specific test procedures. .8 5.5.4 Positioning of the camera. ..8 5.5.5 Exposure, white balance, and focus .9 6 Determination ofgeometric distortion .10 6.1 Local geometric distortion. .10 6.1.1 Numerical definition. 10 6.1.2 Outline of the practical algorithm 10 6.2 Line geometric distortion. 11 6.2.1 Horizontal linedistortion .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 sn Sandardizan rights reserved ii