1、CIE 41 78 I 900bL45 000Lb52 582 H ISBN 3 900 734 47 X COMMISSION INTERNATIONALE DE LCLAIRAGE I NTER NATI ON AL COM M I SS I O N O N I LLU M I NATI ON 1 NTERNATIONALE BELEU CHTU NGSKO M M ISSION LIGHT AS A TRUE VISUAL QUANTITY: PRINCIPLES OF MEASUREMENT Pub. No. CIE 41 ist Edition 19781Reprint 1994 U
2、DC: 612.843.3 Light sense 535.242 Photometry, subjective COPYRIGHT International Commission on IlluminationLicensed by Information Handling ServicesCIE 43 78 9006345 O003653 439 -2- This report has been prepared by the CIE Technical Committee 1.4 ( Vision . It represents the opinion of the majority
3、of the Committee members who represent most member countries of the CIE. This report is recommended for future study and it is not an officially agreed CIE recommendation, approved by the National Committee of the member countries. It should be noted that recommendations in this report are advisory
4、and not mandatory. Ce rapport a t prpare par le Comit Technique CIE 1.4 ( Vision . I1 a t approuv par la majorit du Comit, dans lequel sont reprsents la plupart des pays membres de la CIE, et il est recmmand pour une future tude. Il nest pas une recommandation offcielle de la CIE approuve par les Co
5、mits Nationaux des pays membres. I1 faut noter que toutes les recommandations de ce rapport sont conseilles et non obligatoires. Dieser Bericht wurde vom Technischen Komitee 1.4. , Sehen“ der CIE ausgearbeitet. Er entspricht der Mehrheit der Meinungen des Komitees, in dem die meisten Mitgliedslnder
6、der CIE vertreten sind und wird zum zuknftigen Studium empfohlen. Er ist keine offiziell anerkannte CIE-Empfehlung, die von den Nationalen Komitees der Mitgliedslnder anerkannt wurde. Es mu darauf hingewiesen werden, da alle Empfehlungen dieses Berichts nur als Anleitung dienen und nicht verbindlich
7、 sind. COPYRIGHT International Commission on IlluminationLicensed by Information Handling ServicesCIE 41 78 m 900b145 000Lb54 355 m -3- The following members of the Committee TC-1.4. took part in the preparation of the Technical Report : Les membres suivants du Comit TC-1.4 ont particip la prparatio
8、n du rapport technique : Die folgenden Mitarbeiter des Komitees TC-1.4 haben sich an der Ausarbeitung des Technischen Berichtes beteiligt : Members Membres Mitglieder E. MEYER W. ADRIAN J. KINGSLEY G. VERRIEST V. GAVRIISKI P. KAISER E. KROGH M. AGUILAR J. KINNEY P. LEHTINEN F. PARRA D. PALMER J. SCH
9、ANDA A. TCHETCHIK L. RONCHI M. IKEDA E. ALNAES J. ROUFS S. KONARSKI A. IONESCU T. KRAKAU F. FANKHAUSER J. JOHN D. GLIGO Afrique du Sud Allemagne Australie Belgique Bulgarie Canada Danemark Espagne Etats-Unis Finlande France Grande-Bretagne Hongrie Isral Italie Japon Norvge Pays-Bas Pologne Roumanie
10、Sude Suisse Tchcoslovaquie Yougoslavie COPYRIGHT International Commission on IlluminationLicensed by Information Handling ServicesCIE 41 78 m 9006145 0003655 291 m -4- Summary There are many methods available to photometrists by which visually meaningful assessments of light may be made. All are som
11、ewhat more complicated than the simple use of a physical photometer corrected to V (h). In addition. all require some understanding of the visual system and how it works. However the advantages are sizeable : the assessment of light bears a logical relationship to how we perceive the light. The meth
12、ods are summarized below. For photopic vision, luminances of several cd.m-* or higher, ordinary physical photometers corrected to V (h) give visually accurate measures for small, centrally fixated lights of broad spectral composition. For all other applications a different luminous efficiency functi
13、on should be employed. In order to utilize the appropriate function, one must either measure the spectral distribution of radiant power directly or correct the photocells existing V (A) curve to the appropriate luminous efficiency. An alternate solution is to calculate a new quantity from ordinary l
14、uminance values and from CIE colorimetric measures according to mathematical formulae specifically developed for this purpose. This method is potentially the most useful since different formulae can be developed for different applications (for example, two degree or ten degree fields); at the same t
15、ime it rests on established CIE quantities and no new measures need be developed. For scotopic vision, assessment of radiant power is made with respect to the scotopic luminous efficiency function V (h), either with a physical photometer appropriately corrected or by radiance measurement or visual p
16、hotometry. For mesopic photometry, the light should be assessed for both its photopic and its scotopic contributions. An estimate can be obtained by combining the simple photopic and scotopic luminances non-linearly or a more precise measure by utilizing three, or even better, four quantities, based
17、 on X, Y, Z, and V (A), in the final assessment. Rsum Les photomtristes disposent dun grand nombre de mthodes pour valuer les effets visuels de la lumire. Elles sont toutes passablement plus compliques que le simple usage dun instrument de photomtrie nergtique dont la rponse est corrige pour tenir c
18、ompte de la fonction V (1). Dautre part, elles requirent toutes une certaine comprhension du systme visuel et de son fonctionnement. Toutefois, les avantages sont apprciables : il existe une relation logique entre lvaluation ainsi obtenue et la faon dont nous percevons la lumire. Voici comment on pe
19、ut rsumer ces mthodes. Pour la vision photopique (luminances suprieures ou gales quelques cd m-*) les photomtres nergtiques corrigs selon V (A) donnent des mesures prcises du point de vue visuel lorsquil sagit de stimuli de petite dimension, observs en vision centrale et dont le spectre est largemen
20、t tal. Dans tous les autres cas, il convient davoir recours une fonction defficacit lumineuse diffrente. Pour appliquer celle-ci il faut, soit dterminer directement la rpartition spectrale du flux nergtique, soit appliquer une correction la courbe V (h) utilise dans la cellule photo-lectrique afin d
21、e tenir compte de lefficacit lumineuse qui convient. Une autre solution consiste calculer une quantit nouvelle partir des valeurs ordinaires de la luminance et des mesures colorimtriques de la CIE, en appliquant des formules mathmatiques tablies cet effet. Cette mthode est celle qui offre le plus de
22、 possibilits puisque des formules appropries peuvent tre mises au point pour chacune des applications (par exemple, une pour les champs de 2” et une pour les champs de 10) et que, nanmoins, elle reste base sur les grandeurs CIE dj tablies sans quil soit ncessaire den introduire de nouvelles. Pour la
23、 vision scotopique, lvaluation est faite, soit partir du flux nergtique en tenant compte de la fonction defficacit lumineuse scotopique V (h), soit avec un photomtre nergtique convenablement corrig, soit encore au moyen dune mesure de luminance nergtique ou par photomtrie visuelle. COPYRIGHT Interna
24、tional Commission on IlluminationLicensed by Information Handling Services-5- Pour la photomtrie msopique, la lumire doit tre value tant en ce qui concerne ses effets photopiques que ses effets scotopiques. I1 est alors possible dobtenir une estimation. soit en combinant dune faon non linaire les lu
25、minances photopique et scotopique, soit, si Ion dsire une valuation plus prcise, en combinant dans la formule finale trois ou, mieux encore. quatre quantits bases sur Xln, Yl0, Lo et V (h). Zusammenfassung Dem Photometriker stehen viele Methoden zur Verfgung, nach denen eine visuell sinnvolle Bewert
26、ung des Lichtes vorgenommen werden kann. Alle Methoden sind etwas komplizierter als nur die Anwendung eines V (h) korrigierten physikalischen Photometers. Darberhinaus erfordern alle einiges Verstndnis des visuellen Systems und seiner Funktionsweise. Die Vorteile sind jedoch erheblich : Die Messung
27、des Lichtes steht in logischem Zusammenhang mit der Augenphysiologie, d.h., wie wir das Licht wahrnehmen. Die Methoden sind unten zusammengestellt. Fr photopisches Sehen (Tagessehen), Leuchtdichten von mehreren cd/mz oder hiiher, liefern gewhnliche V (1) korrigierte physikalische Photometer visuell
28、richtige Meergebnisse fr kleine zentral fixierte Lichter breiter spektraler Zusammensetzung. Fr alle anderen Anwendungen sollte eine verschiedene spektrale Helligkeitsfunktion angewendet werden. Zur Anordnung der geeigneten Funktion mu man entweder die spektrale Verteilung der Strahlungsquelle direk
29、t messen, oder die bestehende V )-Kurve der Photozelle an die gltige spektrale Empfindlichkeit anpassen. Eine andere Lsung besteht darin, eine neue Gre aus den gewhnlichen Leuchtdichtewerten und farbmetrischen Gren der CIE nach speziell fr diesen Zweck entwickelten Formeln zu berechnen. Diese Method
30、e ist mglicherweise die ntzlichste, da verschiedene Formeln fr verschiedene Anwendungszwecke entwickelt werden knnen (z.B. zwei Grad oder zehn Grad Felder); gleichzeitig ist sie auf den von der CIE aufgestellten Gren aufgebaut und es brauchen keine neuen entwickelt zu werden. Fr scotopisches Sehen (
31、Nachtsehen) wird die Bewertung der Strahlungsleistung auf die spektrale Empfindlichkeitsfunktion V (1) bezogen, entweder mit einem physikalischen Photometer, der entsprechend korrigiert ist oder durch Strahlungsmessung oder visueller Photometrie. Fr die mesopische Photometrie (Messungen im Dmmerungs
32、sehbereich) sollte das Licht nach beiden Arten, sowohl photopisch (V (1) als auch scotopisch (V (1) bewertet werden. Eine Abschtzung erhlt man durch nichtlineare Addition der photopischen und scotopischen Leuchtdichteanteile oder zur endgltigen Bewertung durch Verwenden von deir oder noch besser vie
33、r Gren, die auf Xlo, Y, Z, und V (A) basieren. COPYRIGHT International Commission on IlluminationLicensed by Information Handling Services CIE 41 78 W OOb145 0003657 Ob4 = -6- Table of contents Chapter 1 PROBLEMS IN PHOTOMETRY 1.1. Introduction 1.2. The Problems of Photometry i .2.1. Inadequacies in
34、 the original determination of V (A). 1.2.2. Inappropriate uses of V (I). a) Problems introduced because an individuals luminous efficiency function differs from b) Problems due to a change of luminous efficiency function with luminance level. c) Problems due to inappropriate viewing conditions. v (
35、4. 1.2.3. Criteria for establishing V (I). 1.3. The Size of the Discrepancies Introduced 1.4. Summary Tables of Some Examples of Discrepancies Introduced by Improper Measuring Techniques Chapter 2 RECOMMENDED PROCEDURES FOR PROVISIONAL USE AND STUDY 2.1. Photopic Photometry (above several cd.m-2) 2.
36、1.1. The appropriate luminous efficiency function. a) Normal photometry. b) Large-field photometry. c) Photometry of narrow band or monochromatic sources. d) Photometry for individuals markedly different than average. e) Photometry for point sources. f) Summary of the choice of appropriate luminous
37、efficiency functions. 2.1.2. Means of measurement. a) Radiance measures. b) Physical photometry. c) Visual photometry. d) Mathematical models in photometry. , 2.3. Mesopic Photometry (between about lop3 and 3 cd.m-2) 2.2. Scotopic Photometry (below about cd.m-) Chapter 3 METHODS FOR ASSESSING LUMINO
38、US EFFICIENCY FUNCTIONS 3.1. Methods 3.1.1. Flicker photometry. 3.1.2. Step-by-step brightness matching. 3,1.3. Direct heterochromatic brightness matching. 3.1.4. Absolute thresholds. 3.1.5. Increment thresholds. 3.1.6. Minimally distinct border. 3.1.7. Visual acuity. 3.1.8. Critical flicker frequen
39、cy. 3.1.9. Colorimetry. 3.1.10. Other methods. COPYRIGHT International Commission on IlluminationLicensed by Information Handling ServicesCIE 43 78 E 900b345 0003b58 TTO = -7- 3.2. The Implications for Photometry 3.2.1. Photopic, small field photometry. a) The model proposed by Guth. 3.2.2. Large fi
40、eld models. a) Kokoschkas system for a total range of light levels. b) Trezona and Clarkes tetrachromatic model. 3.2.3. The future of models in photometry. REFERENCES APPENDIXES A. Luminous efficiency curve for a centrally-viewed, two degree field by heterochromatic brightness B. Luminous efficiency
41、 curve for a .7 to 1.0“ centrally-viewed field by absolute threshold technique. matching. COPYRIGHT International Commission on IlluminationLicensed by Information Handling Services CIE 43 78 9006345 000Lb59 937 -8- Chapter 1 Problems in photometry 1.1. INTRODUCTION This report is dedicated to the m
42、easurement of light. To many who have been making light measurements for years, it may seem superfluous, an indeed it is for the vast majority of the applications around the world. However, there are many instances in which light is measured in the routine way, with light meters and photometers, and
43、 the values yielded bear little or no relationship to the visual impression. The definition of light itself lies behind the problems encountered in photometry. The CIE provides two similar definitions appropriate to the problem at hand : 1. Any radiation capable of causing a visual sensation directl
44、y. 2. Radiation capable of stimulating the organ of vision. In this document we will use a concept consistent with those defined by the CIE but somewhat more general. Light“is radiant power weighted according to the spectral sensitivity of the human eye. The word weighted implies measurement and ind
45、eed photometry concerns the measurement of light. The mathematical expression associated with photometric measures of light is 830 Lu = K, j360 Le, V (2.) dA where L,. = luminance (*) in cd.rn-* . Le.A = spectral radiance in w.m-2 . sr- . nm- V( i.)= spectral luminous efficiency for photopic vision
46、(*) K, = maximum spectral luminous efficacy (683 lumeiis per watt) (*O*). The two definitions and this equation represent major and far-reaching accomplishments of the CIE. Without such a definition, the only means of specifying the physical stimulus for vision would be to give the entire radiant po
47、wer distribution for the source in question. This definition of light makes it an unusual quantity, something not completely physical, not psychological, but psychophysical. Its introduction was somewhat of an historical accident. Humans were using light and measuring it long before physicists learn
48、ed that light was part of the radiant energy spectrum. The unit of measurement was the most common source - the candle - and the means of measuring was a visual brightness match using a standard candle. Since there was always a human doing the measuring, the spectral sensitivity of the human eye was
49、 already built into the procedure of measuring light. The CIE V (A) curve thus became a bridge tying the existing art of photometry to the physicists newly discovered science of electromagnetic energy. Unfortunately, this definition of light brings disadvantages as we11 as advantages. Discrepancies occur in the assessment of light for a wide variety of reasons. This rep
