ASTM C1652/C1652M-21

Standard Test Method for Measuring Optical Distortion in Flat Glass Products Using Digital Photography of Grids

SIGNIFICANCE AND USE
5.1 This test method provides accurate data for evaluation of the optical properties of the glass being inspected.  
5.2 The procedure described is useful for observing the roll wave introduced during the tempering process of flat architectural glass. (1)  
5.3 This test method is also useful for inspection of laminated and tempered automotive glass in transmitted light, in both flat and curved geometries.
SCOPE
1.1 This test method covers the determination of optical distortion of heat-strengthened and fully tempered architectural glass substrates which have been processed in a heat controlled continuous or oscillating conveyance oven. See Specifications C1036 and C1048 for discussion of the characteristics of glass so processed. In this test method the reflected image of processed glass is photographed and the photographic image analyzed to quantify the distortion due to surface waviness. The test method is also useful to quantify optical distortion observed in transmitted light in laminated glass assemblies.  
1.2 The values stated in either SI units or inch-pound units are regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.  
1.3 There is no known ISO equivalent to this test method.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Aug-2021
• ICS: 81.040.20 - Glass in building
• Technical Committee: C14 - Glass and Glass Products
• Drafting Committee: C14.11 - Optical Properties

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation:C1652/C1652M −21
Standard Test Method for
Measuring Optical Distortion in Flat Glass Products Using
1
Digital Photography of Grids
This standard is issued under the fixed designation C1652/C1652M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Transmitted and reflected distortion in annealed, heat strengthened, and tempered glass can be
2
measured by several methods.(1, 2, 3, 4) Qualitative methods are based on the observation of
wavinessintheglassasviewedinofreflectedortransmittedimagesinasetofequidistantlines,called
Zebra Lines. Quantitative measuring techniques are based on several methods, some of which are:
(1) Measuring local curvature using mechanical radius gauges (1, 5, 6, and Test Method C1651).
(2) Moiré Fringe analysis (7, 8).
(3) Double exposure of transmitted grid images (Practice F733).
(4) Projection of an array of round dots (9).
(5) Dual laser beams (10).
The user should be familiar with techniques that are available so as to select the most suitable after
considering the precision, speed, and test specification requirements.The test method described in this
document uses a digital camera to capture a transmitted or reflected image of a set of equidistant lines.
Changes in the spacing of lines are used to quantifying the distortion.
1. Scope 1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers the determination of optical
responsibility of the user of this standard to establish appro-
distortionofheat-strengthenedandfullytemperedarchitectural
priate safety, health, and environmental practices and deter-
glass substrates which have been processed in a heat controlled
mine the applicability of regulatory limitations prior to use.
continuous or oscillating conveyance oven. See Specifications
1.5 This international standard was developed in accor-
C1036 and C1048 for discussion of the characteristics of glass
dance with internationally recognized principles on standard-
so processed. In this test method the reflected image of
ization established in the Decision on Principles for the
processed glass is photographed and the photographic image
Development of International Standards, Guides and Recom-
analyzed to quantify the distortion due to surface waviness.
mendations issued by the World Trade Organization Technical
The test method is also useful to quantify optical distortion
Barriers to Trade (TBT) Committee.
observed in transmitted light in laminated glass assemblies.
1.2 The values stated in either SI units or inch-pound units
2. Referenced Documents
are regarded separately as standard. The values stated in each 3
2.1 ASTM Standards:
system may not be exact equivalents; therefore, each system
C162 Terminology of Glass and Glass Products
shall be used independently of the other. Combining values
C1036 Specification for Flat Glass
from the two systems may result in nonconformance with the
C1048 Specification for Heat-Strengthened and Fully Tem-
standard.
pered Flat Glass
1.3 There is no known ISO equivalent to this test method.
C1651 Test Method for Measurement of Roll Wave Optical
Distortion in Heat-Treated Flat Glass
F733 Practice for Optical Distortion and Deviation ofTrans-
1
This test method is under the jurisdiction of ASTM Committee C14 on Glass
parent Parts Using the Double-Exposure Method
and Glass Products and is the direct responsibility of Subcommittee C14.11 on
Optical Properties.
Current edition approved Sept. 1, 2021. Published November 2021. Originally
3
approved in 2006. Last previous edition approved in 2014 as C1652/C1652M – 14. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
DOI: 10.1520/C1652_C1652M-21. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
2
The boldface numbers in parentheses refer to a list of references at the end of Standards volume information, refer to the standard’s Document Summary page on
this standard. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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C1652/C1652M−21
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2.2 Other Standards: 4. Summary of Test Method
U.S.Patent7345698 OpticalSystemforImagingDistortions
4.1 This test procedure was designed to provide an accurate
in Moving Reflective Sheets (2003)
method of quantifying the opt
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C1652/C1652M − 14 C1652/C1652M − 21
Standard Test Method for
Measuring Optical Distortion in Flat Glass Products Using
1
Digital Photography of Grids
This standard is issued under the fixed designation C1652/C1652M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Transmitted and reflected distortion in annealed, heat strengthened, and tempered glass can be
2
measured by several methods.(1, 2, 3, 4) Qualitative methods are based on the observation of
waviness in the glass as viewed in of reflected or transmitted images in a set of equidistant lines, called
Zebra Lines. Quantitative measuring techniques are based on several methods, some of which are:
(1(1)) Measuring local curvature using mechanical radius gages (gauges (1, 5, 6, and Test Method
C1651)).
(2(2)) Moiré Fringe analysis (7, 8)).
(3(3)) Double exposure of transmitted grid images (Practice F733) ).
(4(4)) Projection of an array of round dots (9)).
(5(5)) Dual laser beams (10)).
The user should be familiar with techniques that are available so as to select the most suitable after
considering the precision, speed, and test specification requirements. The test method described in this
document uses a digital camera to capture a transmitted or reflected image of a set of equidistant lines.
Changes in the spacing of lines are used to quantifying the distortion.
1. Scope
1.1 This test method covers the determination of optical distortion of heat-strengthened and fully tempered architectural glass
substrates which have been processed in a heat controlled continuous or oscillating conveyance oven. See Specifications C1036
and C1048 for discussion of the characteristics of glass so processed. In this test method the reflected image of processed glass
is photographed and the photographic image analyzed to quantify the distortion due to surface waviness. The test method is also
useful to quantify optical distortion observed in transmitted light in laminated glass assemblies.
1.2 The values stated in either SI units or inch-pound units are regarded separately as standard. The values stated in each system
may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two
systems may result in nonconformance with the standard.
1.3 There is no known ISO equivalent to this standard.test method.
1
This test method is under the jurisdiction of ASTM Committee C14 on Glass and Glass Products and is the direct responsibility of Subcommittee C14.11 on Optical
Properties.
Current edition approved May 1, 2014Sept. 1, 2021. Published May 2014November 2021. Originally approved in 2006. Last previous edition approved in 20062014 as
C1652/C1652M – 06.14. DOI: 10.1520/C1652_C1652M-14.10.1520/C1652_C1652M-21.
2
The boldface numbers in parentheses refer to a list of references at the end of this standard.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
C1652/C1652M − 21
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of
the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
3
2.1 ASTM Standards:
C162 Terminology of Glass and Glass Products
C1036 Specification for Flat Glass
C1048 Specification for Heat-Strengthened and Fully Tempered Flat Glass
C1651 Test Method for Measurement of Roll Wave Optical Distortion in Heat-Treated Flat Glass
F733 Practice for Optical Distortion and Deviat
...