SAE J 985-2002 Vision Factors Considerations in Rearview Mirror Design.pdf

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1、 _ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising ther

2、efrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2016 SAE International All rights reserved. No part of this

3、publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-49

4、70 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit HTTP:/STANDARDS.SAE.ORG/J985_201611 SURFACE VEHICLE INFORMATION REPORT J985 NOV2016 Issued 1967-04 Revised 1995-06Reaf

5、firmed 2016-11 Superseding J985 FEB2009 Vision Factors Considerations in Rearview Mirror Design RATIONALE J985 has been reaffirmed to comply with the SAE five year review policy. 1. ScopeThe design and location of rear-viewing mirrors or systems, and the presentation of the rear view tothe driver ca

6、n best be achieved if the designer and the engineer have adequate references available on thephysiological functions of head and eye movements and on the perceptual capabilities of the human visualsystem. The following information and charts are provided for this purpose. For more complete informati

7、on ofthe relationship of vision to forward vision, see SAE SP-279.2. References2.1 Applicable PublicationsThe following publications form a part of this specification to the extent specifiedherein.2.1.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE Paper 6

8、50464Automobile Driver Eye Position, Meldrum, James F., SAE Transactions, Vol. 74, (1966)SAE SP-279Visual Considerations: Man, the Vehicle, and the Highway, Schmidt, I., and Connolly,Paul L., SAE, March, 19662.2 Related PublicationsThe following publications are provided for information purposes onl

9、y and are not arequired part of this document.Bioastronautics Data Book, Scientific and Technical Information Division, National Aeronautics and SpaceAdministration (Washington, DC, NASA SP-3006), 1964Design Aspects for Rear Vision in Motor Vehicles, SP-253, SAE, March 1964The Measure of Man, Dreyfu

10、ss, Henry, New York: Whitney Library of Design, 1959Handbook of Human Engineering Data, Tufts College Institute for Applied Experimental Psychology, SpecialDevices Center, Office of Nava Research, Project Design, NR 78-3001, 1951Human Engineering Guide to Equipment Design, Morgan, C.T., Cook, J.S.,

11、et al., New York: McGraw-Hill,Inc., 1963Human Engineering Guide for Equipment Designers, Woodson, W.E., Berkeley: University of CaliforniaPress, 19603. Vision Considerations in Rearview Mirror Design3.1 IntroductionThe design and location of rearview mirrors to provide adequate driver rear vision ca

12、n best beperformed when a basic knowledge of the physiological and perceptual capabilities of the drivers visualsystem are understood.3.2 Drivers Field of ViewThe field of view for each eye of the driver extends in a horizontal plane 150 degrees(90 degrees outside and 60 degrees inside from the forw

13、ard line of sight.) It is assumed that the forward line ofsight is directly in line with the longitudinal axis of the vehicle. It can be seen from (see Figure 1) that the fieldsof view (left eye plus right eye) overlap 120 degrees, thus defining a binocular field of view. The verticalboundary to the

14、 binocular field of view is approximately 50 to 55 degrees above and 60 to 70 degrees belowthe forward line of sight (see Figure 2).FIGURE 1HORIZONTAL EXTENT OF THE BINOCULAR VISUAL FIELDFIGURE 2BINOCULAR VISUAL FIELD WITH HEAD AND EYES FIXED_ SAE INTERNATIONAL J985 NOV2016 1 of 43.3 Visual Fields w

15、ith Head and Eye MovementIn the design and engineering of rearview mirrors and mirrorsystems, every effort should be made to allow the driver to maintain visual attention to the front of the vehicle.Distracting the drivers attention from viewing the road ahead should be kept to a minimum. Eye and he

16、admovement are two factors affected by the placement of rearview mirrors and must be considered (see Figures3 and 4).Horizontal eye rotation is optimal at 15 degrees to left and right of the forward line of sight; however, the eyescan turn 30 degrees in one rapid, smooth movement.1Vertical eye rotat

17、ion is optimal at 15 degrees up anddown from the forward line of sight, while maximum eye rotation is 45 degrees upward and 65 degreesdownward.Easy horizontal head movement is considered 45 degrees to the left and right of the forward line of sight, whilemaximum is 50 degrees up and down.FIGURE 3HOR

18、IZONTAL EXTENT OF HEAD AND EYE MOVEMENTFIGURE 4VERTICAL EXTENT OF HEAD AND EYE MOVEMENT1. The human eye does not rotate around a single point. Thus, upon temporal (outward) gaze, the eye moves rearward approximately 0.5 mm and in nasal (inward) gaze, the eye moves forward approximately 0.6 mm._ SAE

19、INTERNATIONAL J985 NOV2016 2 of 4To reduce driver fatigue and improve visual efficiency, the entire rear vision mirror is best located within thedrivers binocular field of view while looking straight ahead. This area extends horizontally 60 degrees to theleft and right of the forward line of sight (

20、45 degrees easy head movement plus 15 degrees optimal eyerotation). Vertically, this area extends 45 degrees up and down from the forward line of sight (30 degrees easyhead movement plus 15 degrees optimal eye rotation). If necessary, the horizontal limit of head and eyemovement may be extended to 7

21、5 degrees left and right of the forward line of sight to view a mirror (45degrees easy head movement and 30 degrees eye rotation). A driver can combine head and eye movementthat exceeds the previous limits, but should not be required to do so repeatedly or for long periods of time.3.4 Perceptual Cha

22、racteristics of the EyesThe ability of the eye to perceive detail, form, color, and motion ishighest in the area immediately surrounding the forward line of sight. Visual perception reduces as distancefrom the forward line of sight increases.The perception of traffic events to the rear is reduced wh

23、en a mirror is placed away from the forward line ofsight. Beyond a given area, a rearview mirror may cease to stimulate the drivers visual system sufficiently toalert the presence of traffic activity to the rear. The farther a mirror is placed away from the forward line ofsight, driver perception is

24、 reduced from forward traffic events while looking into the rearview mirror.3.5 Enhancement of Visual PerceptionWhen rear vision mirrors are placed within the drivers binocular field ofview (as opposed to outside the binocular field of view), the retina of each eye is stimulated to produce astronger

25、 image to the rear so that: (a) motion perception is increased and (b) reduced reaction time for driverhead and eye movement.Rearview mirrors provide better visual perception when the width allows a driver to view images with both eyessimultaneously. This means the effective aperture (opening or wid

26、th) of the mirror must be wide enough toallow the line of sight for each eye to view the mirror. Interpupillary distance is the distance between the linesof sight for each eye and is approximately 65 mm. It is desirable that the mirror should be wide enough toallow binocular viewing with reasonable

27、changes in the lateral positioning of the drivers eyes.The vertical dimension of a rearview mirror or system should adequately provide for changes in the verticalpositioning of the drivers eyes. An insufficient vertical mirror dimension can restrict a drivers “eye freedom”and often a physical eye or

28、 head adjustment must be made to use the mirror.3.6 Adjustability of MirrorsThe variation and position in driver eye positions can be ascertained from SAEPaper 650464. However, once a driver has adjusted the mirror, the eye positions may change considerablythroughout the duration of a single trip. T

29、he vertical dimension is most critical. It must allow the drivers eyesto move up or down without having the line of sight encroach upon the upper or lower edge of the mirror. Thedriver should not be required to make unnecessary physical or psychological adjustments in order to use themirror once it

30、is adjusted.3.7 Illumination and Visual Perception3.7.1 TWILIGHT AND DAWNWhen illumination falls to levels experienced at twilight and dawn, visual perceptionsuffers. Contrast of vehicles and objects on the highway is greatly reduced. Contrast approaches zero (nocontrast) shortly before dark. For be

31、st visual perception of rear traffic events during low sunlight hours, arearview mirror should have as high (bright) of a reflection as possible to provide the driver with a rear viewthat is close to the brightness of the front view. A rearview mirror that provides a lower light transmittance(for th

32、e rear environment) than the front environment provides can cause difficulty for the eyes to adjust tothe contrast, increasing viewing time into the mirrora condition to be avoided. A 60-year-old driver mayrequire three times more light to see than a 20-year-old driver._ SAE INTERNATIONAL J985 NOV20

33、16 3 of 43.7.2 VISION IN NIGHT DRIVINGVisibility during night driving is handicapped by the presence of glare or reflectedglare sources within the drivers field of view. Headlight glare from oncoming vehicles and overheadroadway lighting glare can reduce forward visibility. Likewise, headlights from

34、 following vehicles can bereflected from the rearview mirror into the drivers eyes, reducing forward visibility to the roadway ahead. Allof these glare sources add-up, so every effort should be made to reduce or eliminate such glare. Glaresources may be a cause of both irritation and fatigue to driv

35、ers at night.The closer the rearview mirror is placed to the drivers forward line of sight, the greater the reduction invisibility and the greater the discomfort due to the glare reflected from the mirror. The reduction of this glarecan be reduced by incorporating a low light transmittance function

36、into the mirror. The use of such a functioncan be applied when glare sources are temporarily disabling to the driver. A day-night mirror can provideboth high and low light transmittance and should be easily activated when glare sources are high. The mirrorshould be easily returned to high light tran

37、smittance when glare sources are not as high, in order to perceivetraffic events to the rear with as little handicap as possible. Older drivers are more susceptible to glarediscomfort and visibility loss. After glare, a 60-year-old driver may require two times as long to recover fromglare as a 20-year-old driver.PREPARED BY THE SAE DRIVER VISION STANDARDS COMMITTEE_ SAE INTERNATIONAL J985 NOV2016 4 of 4