1、Designation: D7879 13Standard Test Method forDetermining Flax Fiber Widths Using Image Analysis1This standard is issued under the fixed designation D7879; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A
2、 number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method involves the measurement and analysisof two-dimensional projections of flax fibers using imageanalysis software in th
3、e longitudinal plane to determine theaverage and distribution of fiber widths.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with i
4、ts use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D123 Terminology Relating to TextilesD1776 Practice for Conditioning a
5、nd Testing TextilesD6798 Terminology Relating to Flax and Linen3. Terminology3.1 Definitions:3.1.1 For all terminology related to Flax and Linen seeTerminology D123.3.1.1.1 The following terms are relevant to this standard:average fiber width (m).3.1.1.2 For definitions of all other textile terms se
6、e Termi-nology D6798.4. Summary of Test Method4.1 This test method involves the preparation of flax fibersfor digital capture, the scanning of the fibers for analysis, andthe calibration and standardization of the image processing.From the image analysis, the arithmetic mean and its standarddeviatio
7、n, median, and numerical distribution of the fiberwidths are calculated.5. Significance and Use5.1 Longitudinal preparation is much quicker and lessdamaging than cross-sectional analysis and allows the fibers tobe evaluated in their natural state.5.2 This test method provides measurement of a flax f
8、iberspecimen that uses less specimen preparation, produces con-sistent results, and minimal specimen modification. It has beenshown that the median values of width correlate very well withthe Optical Fiber Diameter Analyzer (OFDA), an apparatusdeveloped for measuring the value and distribution of wo
9、olfiber diameters.6. Interferences6.1 Out of focus objects.6.2 Real resolution of image capturing device impactsmeasurements.6.3 Fingerprints, cracks, scratches, tape, dust and otherimpurities (non-fibrous objects) on the glass slides can biasmeasurement results.6.4 Results will be incorrect or misl
10、eading if the operator ofthe software has not properly set up the image captureparameters.6.5 Image processing techniques employed to completemissing or incompletely developed fiber boundaries must beused with caution as false boundaries may be created.6.6 Vibrations or movement of the sample during
11、 imagecapture can blur the image and must be minimized or elimi-nated when using automatic image analysis.6.7 Non-uniform illumination can influence feature detec-tion and threshold using automatic image analyzers.6.8 Operation of the equipment in a non-environmentallycontrolled room may result in f
12、iber shape deviations afterinitial fiber conditioning has occurred.7. Apparatus7.1 Fiber Preparation Apparatus:1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.17 on Flax and Linen.Current edition approved Dec. 1, 2013.
13、Published January 2014. DOI: 10.1520/D7879-142For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM I
14、nternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17.1.1 Acoarse comb or other device used to distribute fibersto create a single focal plane and better enable fiber edgedetection.NOTE 1Excessive overlap of fibers reduces the possibility of observ-ing a
15、ll of the fibers in a single focal plane.7.1.2 Two flat surfaces capable of compressing the samplewhere at least one surface is optically transparent.NOTE 2The purpose of the flat and compressive surfaces is to createa uniform focal plane to capture a majority of fibers in one focal plane.7.2 Image
16、Capture Hardware:7.2.1 The hardware device must capture an image with areal optical resolution of at least 4000 dpi (1 dot = 6.35 m).The hardware device must be able to provide a digital image ina RAW format for storage and analysis.NOTE 3Stated resolution does not necessarily correspond to the real
17、optical resolution.7.2.2 The apparatus must be able to create a sharp image byautomatic or manual focusing.7.3 Image Analysis Software:7.3.1 Software must be capable of importing a digital image(including RAW formatted images), performing featureextraction, and calculating fiber widths for further a
18、nalysis andelectronic data export.7.3.2 Software must be capable of manual or automaticadjustments so that it measures the specimen of interest (forexample, flax fiber and fiber bundles 8-100 m).7.3.3 Software must be capable of displaying the originalimage with an overlay of the feature extraction
19、image to adjustthe threshold for proper edge detection.8. Reagents and Materials8.1 Materials may include National Institute of Standardsand Technology (NIST) traceable calibration images, syntheticfibers of known diameter, and components of the apparatus. Noreagents are used.9. Hazards9.1 There are
20、 no known hazards.10. Sampling, Test Specimens, and Test Units10.1 This test method describes the measurement of thesample of interest taken from the lot and is not necessarily anaccurate representation of the lots distribution. No less thanthree test specimens must be taken; additional specimens wi
21、llbe dependent on the accuracy required by the end user and thenatural variation of the fibers. Due to this variation, it issuggested that at least 100 fibers be analyzed from eachspecimen.10.1.1 Gently loosen flax fibers such that individual fiberscan be accessed and extracted to produce a laborato
22、ry sample.NOTE 4The specimen should be handled gently to reduce fiber widthreduction due to fiber separation during fiber extraction. Unattached shive,trash, and other impurities should be removed by gentle shaking.10.1.2 Take the test specimen fibers by random samplingfrom the laboratory sample.10.
23、1.3 Use a coarse comb or other device to distribute testspecimen fibers on a flat surface thus creating a single focalplane and enabling better fiber edge detection.NOTE 5Fine combs, multiple combings, or rigorous combing, orcombination thereof, can reduce fiber width measurements.10.1.4 Use two fla
24、t surfaces capable of compressing andsecuring the fiber specimen where at least one surface isoptically transparent to create a uniform focal plane.11. Preparation of Apparatus11.1 Follow manufacturers guidelines.12. Calibration and Standardization12.1 The system must be calibrated for accurate fibe
25、r widthmeasurement.12.1.1 The scanner and software must be periodically cali-brated according to manufacturers recommendations usingimages of known dimensions (for example, NIST traceableimages).12.1.2 Users are required to evaluate fiber generated imagesfor uniform edge detection and optimize the s
26、oftware param-eters for optimal image overlay. The software must be cali-brated to visually depict the fibers edge (generated fiberimages should overlay original images with proper edgedetection).NOTE 6Edge detection may be dependent upon light source decay.13. Conditioning13.1 Bring the laboratory
27、flax fiber sample from the prevail-ing atmosphere to moisture equilibrium for testing which is 216 1C (70 6 2F) and 65 6 2 % relative humidity and checkthe equilibrium as directed in Practice D1776. No precondi-tioning is required.14. Procedure14.1 Prepare fiber test specimen for image capture.14.2
28、Follow manufacturers guidelines to acquire image offiber test specimen.14.3 Import the digital image, perform feature extraction,and determine fiber widths using the image analysis software.14.4 Repeat 14.1 14.3 for remaining fiber test specimens.15. Calculation or Interpretation of Results15.1 Calc
29、ulate fiber width statistics (for example, arithmeticmean fiber width, sample standard deviation, and median).NOTE 7Image analysis software may automatically generate thesestatistics.15.2 Additional reporting will be defined by agreementbetween supplier and user of the data.16. Report16.1 Report the
30、 following information:16.1.1 Identity of the laboratory sample.16.1.2 Material type.16.1.3 One typical image.16.1.4 Name of testing laboratory.D7879 13216.1.5 Type and length of preconditioning used.16.1.6 Temperature and relative humidity conditions duringtesting.16.1.7 Image capture hardware used
31、.16.1.8 Optical resolution used.16.1.9 Type of image analysis software used, softwareparameters, and version.16.1.10 Name of operator.16.1.11 Date of the test.16.1.12 Number of specimens tested.16.1.13 Number of fibers examined.16.1.14 Arithmetic mean fiber width.16.1.15 Sample standard deviation.16
32、.1.16 Median.16.1.17 Fiber width distribution curve (for test specimensand laboratory samples).16.1.18 Minimum and maximum width used during imageanalysis to isolate the objects of interest.17. Precision and Bias17.1 PrecisionThe mean, standard deviation, and 95 %repeatability limit (2.8 sample stan
33、dard deviation) of within-laboratory samples tested with the same method, equipment,laboratory, and operator for various sample of flax fiber areshown in Table 1.17.2 BiasWith the limitation imposed by within-laboratory evaluation, this test method has no known bias.18. Keywords18.1 fiber diameter d
34、istribution; fiber width measurement;flax fiber; image analysis; slide scannerASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the valid
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39、PYRIGHT/).TABLE 1 Mean, Standard Deviation, and Within-laboratoryRepeatability LimitSample Type1Statistic Thickness (m)1 Mean 28.59Standard deviation 2.65Repeatability Limit 7.412 Mean 56.40Standard deviation 2.88Repeatability Limit 8.073 Mean 58.63Standard deviation 6.63Repeatability Limit 18.554 M
40、ean 27.19Standard deviation 1.65Repeatability Limit 4.635 Mean 24.61Standard deviation 0.23Repeatability Limit 0.646 Mean 32.36Standard deviation 6.83Repeatability Limit 19.13AThe average and standard deviation are from three samples. The repeatabilitylimit is derived by multiplying 2.8 by the sample standard deviation in accordancewith Form and Style of ASTM Standards, Section A21.2.5.D7879 133
