ISO INTERNATIONAL STANDARD 20462-2 First edition 2005-11-01 Photography Psychophysical experimental methods for estimating image quality Part 2: Triplet comparison method Photographie Methodes psychophysiques experimentales pour estimer la qualite d'image - Partie 2: Methode comparative du triplet Reference number ISO 20462-2:2005(E) @ ISO 2005 Copyright International Organization for Standardization ted without license from IHS Not for Resale ISO 20462-2:2005(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by IsO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below ?ISO2005 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, ISO's member body in the country of the requester. ISO copyright office Case postale 56 . CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland yemainagazaiandardizato @ISO2005-All rights reserved mittedwithoutlicense from IHS Not for Resale ISO 20462-2:2005(E) Contents Page Foreword. Introduction 1 Scope 2 Terms and definitions. 3 Two-step psychophysical method.. 4 Experimental procedure 4.1 Step 1 4.2 Step 2 Annex A (informative) Comparison between a paired comparison and a triplet comparison Annex B (informative) Number of sample combinations for triplet comparison. Annex C (informative) Standard portrait images Annex D (informative) Performance of the triplet comparison method. Annex E (informative) Scheffe's method .. Annex F (informative) Conversion of Scheffe's scale to JND.. 22 Bibliography. 25 CopyrghtInternationalOrganizansadardizaoghtsreserved ii se from IHS Not for Resale ISO 20462-2:2005(E) Foreword IsO (the International Organization for Standardization) is a worldwide federation of national standards bodies (isO member bodies). The work of preparing International Standards is normally carried out through IsO technical committees. Each member body interested in a subject for which a technical committee has beer non-governmental, in liaison with isO, also take part in the work. sO collaborates closely with the International Standards are drafted in accordance with the rules given in the ISO/lEC Directives, Part 2 The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent ISO 20462-2 was prepared by Technical Committee ISO/TC 42, Photography. method for estimating image quality: —Part1:Overviewof psychophysicalelements Part 2: Triplet comparison method Part 3: Quality ruler method ISO 2005 - All rights reserved ISO 20462-2:2005(E) Introduction This part of iso 20462 is necessary to provide a basis for visually assessing photographic image quality in a precise, repeatable and efficient manner. This part of isO 20462 is needed in order to evaluate various test as part of the work needed for future revisions of IsO 12232. The opportunities to create and observe images using different types of hard copy media and soft copy displays have increased si