Verification Theory. Verification As Easy As A, B, C

Transcription

1 Verification Theory Verification As Easy As A, B, C

2 Many terms...

3 easy explanation ANSI -- American National Standards Institute X ANSI s Print Quality Standard CEN -- Committee for European Normalization CEN s equivalent to ANSI X3.182 ISO/IEC SC31 -- International Standards Organization / International Electrotechnical Council Subcommittee 31 on Automatic Identification and Data Collection WG3 -- SC31 s Work Group on Conformance ISO/IEC ISO equivalent to ANSI X3.182 SRP -- Scan Reflectance Profile the basis for all X3.182 / 1635 / test measurements QZ, ERN, SC, etc. -- Test parameters found in X3.182 / 1635 / 15416

4 Why Verify? Verification versus Validation Validation is checking to see if the bar code symbol will decode and if the data in it exists in the database Verification is checking the overall print quality against a set of standards or specifications

5 Why Verify? Without verification, bar codes entering the automatic data collection system run the risk of not scanning efficiently (or at all) or may contain substitution data errors Quality standards being adopted worldwide such as ISO 9000 demand traceability and accountability Bar code applications include symbol and format specifications as part of quality determination A point to remember scanners are not verifiers. Scanners are designed to read verifiers are a quality control instrument

6 What to Verify Parameters that can be measured visually, without using equipment Parameters that should be measured using verification equipment Traditional Quality Parameters ANSI / CEN / ISO Bar Code Print Quality Parameters

7 Human Readable Characters Are the characters the correct size? Is the placement in relation to the bar code correct?

8 Symbol Placement / Location Application guidelines and specifications have been put together to guide you through the proper placement of your symbol for your specific package type and use

9 Symbol Placement / Location For symbols placed on containers used for shipping as well as being scanned at the point of sale, logistic symbol placement guidelines should be followed VCR Player/Recorder Qty: Bleach-O 64 oz

10 Symbol Height / Truncation In POS scanning applications scanners read EAN/UPC symbols as two halves and then piece the halves together into a complete number shorter symbols decrease the opportunity to get a good scan Do not truncate (shorten height) truncate only when there is no room for the full symbol height left half right half

11 Equipment Based Verification Methodologies Traditional Analysis Parameters ANSI X CEN EN ISO/IEC Bar Code Print Quality

12 What are Traditional Quality Parameters? Traditional - based on linear measurements of bar/space widths as seen by the human eye, reflectance values of background versus bar color when measured through a red filter and the correct data encodation

13 Decode / Encodation = 1A2B3C Does the bar code pattern represent the proper series of characters?

14 Contrast high enough? Print Contrast Signal PCS = Refl.light Refl.dark / Refl.light (minimum 75%) Red on white looks OK to us, but not to the scanner

15 Average Bar Deviation Represents aim bar width Represents amount of gain or loss allowable

16 Quiet Zones / Light Margins Allow for the appropriate quiet zones QZ / LM QZ / LM Clear areas around the bar code necessary for the scanner to properly recognize and read the bar code. They are free of wording, graphics, closures, perforations or scores.

17 Wide to Narrow Ratio 3:1 Ratio Width of the wide elements when compared to the width of the narrow elements.

18 Check Character for UPC/EAN =20 (20 X 3 = 60) = =85 Check Character = the number added to the sum of 85 is a multiple of 10. The check number = 5 Example is a UPC Modulo 10 Check Character Calculation

19 What are ANSI/CEN/ISO Quality Parameters? ANSI / CEN / ISO - Evaluation based on how the scanning or reading equipment sees the bar code. Quality parameters are calculated using reflectance values from the bar code s Scan Reflectance Profile (SRP). 100% Reflectance Quiet Zone Spaces Quiet Zone 0% Reflectance Bars

20 Verifier Apertures & Wavelengths Wavelength Aperture

21 Verifier Apertures Aperture Diameter Too Large Aperture Diameter Too Small

22 Recommended Aperture Sizes X Dimension Range X mm X mm < X mm < X mm < X mm < X mm < X mm < X Aperture Size (3 mil) mm (5 mil) mm (10 mil) mm (20 mil) mm Note: 6 mil ( mm) aperture specified for UPC/EAN

23 ANSI / CEN / ISO Pass/Fail Quality Parameters A(4) or F(0) Edge Determination Minimum Reflectance Edge Contrast Minimum Decode Quiet Zone

24 ANSI/CEN/ISO Graded Quality Parameters A(4), B(3), C(2), D(1) or F(0) Symbol Contrast Modulation Defects Decodability

25 ANSI/CEN/ISO Scan (SRP) Parameters parameters for each scan path Edge Determination Pass = A Minimum Reflectance 3% 3% = A Symbol Contrast 70% 70% = A Edge Contrast %= %= A Modulation 55% 55% = C Defects 17% 17% = B Decode Pass = A Decodability 60% 60% = B Quiet Zones Pass = A

26 ANSI/CEN/ISO Scan (SRP) Grades Lowest parameter grade for each scan path = Scan or SRP Grade Edge Determination Pass = A Minimum Reflectance 3% 3% = A Symbol Contrast 70% 70% = A Edge Contrast %= %= A Modulation 55% 55% = C Defects 17% 17% = B Decode Pass = A Decodability 60% 60% = B Quiet Zones Pass = A Courtesy of Uniform Code Council, Copyright 1998, All Rights Reserved

27 ANSI X3.182 EN1635 ISO/IEC15416 Grading scan paths for each symbol

28 ANSI/CEN/ISO Symbol Grades The average of ten SRP grades equals the symbol grade Scan Grade 1 B = Scan Grade 2 C = Scan Grade 3 C = Scan Grade 4 B = Scan Grade 5 B = Scan Grade 6 B = Scan Grade 7 C = Scan Grade 8 B = Scan Grade 9 A = Scan Grade B = Average Grade or or B

29 ANSI/CEN/ISO Grading Scan (SRP) Grade The ANSI/CEN/ISO Scan or SRP Grade is the lowest grade achieved of all the ANSI / CEN / ISO Parameters in a single Scan or SRP analysis Overall Symbol Grade The Overall Symbol Grade is based on ten (10) scans (SRPs) and the average of their resultant Scan or SRP Grades The ten (10) scans are for vertical redundancy as well as statistical stability

30 Minimum Grades are based on your Application Example: The minimum UCC/EAN Symbol Grades are Symbol Application or Use Minimum Grade EAN/UPC All applications 1.5 GPA (C) UCC/EAN-128 All applications 1.5 GPA (C) ITF-14 X < 25 mil ( mm) 1.5 GPA (C) X > 25 mil ( mm) 0.5 GPA (D)

31 ANSI/CEN/ISO Print Quality Flow Chart EDGE DETERMINATION Global Threshold (GT) = Rmin + (SC/2) PASS or FAIL REFLECTANCE MINIMUM Rmin.5* Rmax = PASS Rmin >.5* Rmax = FAIL EDGE CONTRAST MINIMUM Rs min - Rb max (worst pair) 15% = PASS < 15% = FAIL SYMBOL CONTRAST SC = Rmax - Rmin 70% = A/4 55% = B/3 40% = C/2 20% = D/1 < 20% = F/0 MODULATION EC min / SC.70 = A/4.60 = B/3.50 = C/2.40 = D/1 <.40 = F/0

32 ANSI/CEN/ISO Print Quality Flow Chart DEFECTS ERNmax / SC.15 = A/4.20 = B/3.25 = C/2.30 = D/1 >.30 = F/0 DECODABILITY.62 = A/4.50 = B/3.37 = C/2.25 = D/1 <.25 = F/0 DECODE PASS or FAIL PROFILE NUMERIC GRADE SYMBOL GRADE CONVERSION 4.0 = A 3.5 to = B 2.5 to = C 1.5 to = D 0.5 to = F less than 0.5

33 Print Quality Check List Quality Factors ANSI, or Trad l Visual Verifier Edge Determination (Global Threshold) A X Reflectance Minimum A X Edge Contrast Minimum A X Symbol Contrast A X Modulation A X Defects A X Decodability A X Decode A X Quiet Zones (Clear Margins) A X X Print Contrast Signal (PCS) T X Wide/Narrow Ratio T X Average Bar Deviation T X Check Character Calculation T X Symbol/Human Readable Match T X Symbol Location relative to Label T X Label Size T X Symbol(s) Placement on Product T X

34 Test Card for ANSI / CEN / ISO Verifiers Calibrated Conformance Standard is used to verify the verifier Traceable to NIST Important training tool for personnel in the correct use of verifiers Courtesy of Uniform Code Council, Copyright 1998, All Rights Reserved

35 and in the end. Though as highly technical, even confusing, in nature all of this is ANSI / CEN / ISO based verifiers do all the work for you! In the end the results from your verifier, with the proper technical support, will help you to maintain proper quality levels when printing.