INTERN CEMS GT-6E-2009 Distinctness Of Image (D O I )《图像的特异性(D O I)》.pdf

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1、 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2009 by Navistar, Inc. AUGUST 2009 Page 1 of 3 NAVISTAR, INC. CEMS (CORPORATE ENGINEERING MATERIAL SPECI

2、FICATION) NUMBER: CEMS GT-6E TITLE: Distinctness Of Image (D. O. I.) CURRENT ISSUE DATE: August 2009 WRITTEN/REVIEWED BY: Materials Engineering APPROVED BY: Materials Engineering SUPERSEDES ISSUE OF: August 2001 PRINTED COPIES OF THIS DOCUMENT MUST BE VERIFIED FOR CURRENT REVISION This specification

3、 may involve hazardous materials, equipment, and procedures. This specification does not purport to address all of the safety issues associated with its use. The user is responsible to consult appropriate safety and health practices and to determine the applicability of regulatory limits prior to us

4、e. Change Notice: Replaced “International Truck and Engine Corporation” with “Navistar, Inc.” per corporate directive. 1.0 SCOPE This is a method for determining the distinctness of image or clarity of a painted surface. 2.0 APPARATUS 2.1 A portable fluorescent lamp, Burgess Safari Light, catalog nu

5、mber 165/3, or Eveready Captain Light, model 160 WB, fitted with a standard image film strip* and legs to keep the image film 152 mm (approx. 6 inches) from the test surface. See Figure 1. 2.2 A control standard* with an assigned value of 8 D.O.I. P OR T AB L E F L UOR E S C E N T L I G HTC L E A R

6、P A C KI NG P L AT ES T AND A R D I M A G E F I L M S T R I PT R A NS P A R E NT C OV E RL E G AS S E M B L Y T O KE E P F I L M15 0 m m ( A P P R OX. 6 i n c h es )F R OM T E S T S UR F AC EFI GU R E 1 - D .O .I. A PPA R A TU S* The standard image film strip and the control standard are available f

7、rom Materials Engineering, Navistar, Inc., P. O. Box 1109, Fort Wayne, IN 46801-1109. Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: CEMS GT-6E TITLE: Distinctness Of Ima

8、ge (D.O.I.) CURRENT ISSUE DATE: August 2009 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2009 by Navistar, Inc. AUGUST 2009 Page 2 of 3 3.0 PROCEDURE

9、3.1 Ensure that surface to be measured is clean and free of oil and dirt. 3.2 Measurements will be made in an area where general lighting does not exceed 800 lux (75 foot candles). General lighting in excess of this amount can overpower the light source of the D.O.I. meter, usually resulting in lowe

10、r readings. 3.3 Position the D.O.I. meter with the smallest image forming patterns toward the right. Determinations will be made from either side of the instrument by observing the D.O.I. of the panel at approximately 15-30 degrees from the vertical with the eyes at a distance of 25-30 cm (approx. 1

11、0-12 inches) from the panel. Adjacent to each size of image forming pattern is a rating number (10, 9, 8, 7, etc.). See Figure 2. These values are used to rate D.O.I. * Insert Graphics Here * GRAPHICS NOT AVAILABLE AT THIS TIME CONTACT: CORPORATE STANDARDS PO BOX 1109 FORT WAYNE INDIANA 46801 1109 3

12、.4 Repeat the above evaluation on the painted surface of the sample of unknown D.O.I. Figure 2 - Image Forming Patterns (Landolt Rings) 3.5 Observe the 8 D.O.I. control standard. Determine the pattern on which all circles and their openings are clearly and distinctly seen. Observe the circle opening

13、s on the next smaller pattern. If only a few of the openings are visible, the rating is that of the entirely visible pattern. If at least 50% of the openings are visible, then a rating halfway between these two pattern numbers should be reported. For example, if the circles on pattern 8 are entirely

14、 visible and the circles on the next smaller pattern 9 are at least 50% visible, a rating of 8.5 should be reported. However, if only a few of the circles on pattern 9 are visible, the reported rating should be 8. 4.0 RATING NORMALIZATION Every observer has a different degree of visual acuity. Conse

15、quently, evaluations from each observer must be normalized using the following technique in order to put all ratings on a common basis. 4.1 Unless otherwise specified, a control standard with an assigned value of 8 D.O.I. will be used. This is important for the first few readings of each day and bec

16、omes more significant when new operators are assigned to the job. 4.2 The difference between the assigned value and the observed value of the control standard will be arithmetically added to the observed value of the unknown sample. In this way, D.O.I. ratings are normalized for all observers. 4.3 N

17、umerical examples of the normalization procedure for each of two observers are as follows: Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: CEMS GT-6E TITLE: Distinctness O

18、f Image (D.O.I.) CURRENT ISSUE DATE: August 2009 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2009 by Navistar, Inc. AUGUST 2009 Page 3 of 3 4.3.1 Obs

19、erved D.O.I. values: Observed D.O.I Values Specimen Assigned D.O.I. Operator 1 Operator 2 Control Standard 8 7 9 Unknown Sample - 7.5 9.5 4.3.2 Normalization calculation: Normalized rating = Observed D.O.I. for unknown sample plus D.O.I. where D.O.I. = Assigned D.O.I. for control standard minus the

20、observed D.O.I. for control standard. For operator 1, normalized rating = 7.5 + (8 - 7) = 7.5 + (+1) = 8.5 For operator 2, normalized rating = 9.5 + (8 - 9) = 9.5 + (-1) = 8.5 5.0 REPORT Report the normalized distinctness of image (D.O.I.) rating to the nearest 0.5. Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-