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بنام خدا کاربرد کامپیوتر در مهندسی صنایع (21774 ( Lecture 9 The barcode

بنام خدا کاربرد کامپیوتر در مهندسی صنایع (21774 ( Lecture 9 The barcode. Barcode SYMBOLOGIES. LASER PRINTER. WRONG. RIGHT. Bar Growth. Restrict scaling on the X dimension Undercut bars and grow spaces equally. Will not read OR Substitution Errors (CODE 39). Dirty Laser Printer.

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بنام خدا کاربرد کامپیوتر در مهندسی صنایع (21774 ( Lecture 9 The barcode

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  1. بنام خدا کاربرد کامپیوتر در مهندسی صنایع (21774( Lecture 9 The barcode

  2. Barcode SYMBOLOGIES

  3. LASER PRINTER

  4. WRONG RIGHT Bar Growth • Restrict scaling on the X dimension • Undercut bars and grow spaces equally

  5. Will not read OR Substitution Errors (CODE 39) Dirty Laser Printer CLEAN DIRTY

  6. Bar Code PrintingFuture Trends • Direct Part Marking • Ink Jet • Dot Peening • Laser Etching

  7. DPM Bar Code Reader • Laser to Illuminate • CCD to Read

  8. Invisible (IR) Inks

  9. IR Reading

  10. Selecting a Bar Code Printer • Environment • Indoor vs. Outdoor • Clean vs. Dirty • Media • Labels, Direct Marks, Paper • Ruggedness • Symbol Size • Flexibility

  11. Bar Code Reading

  12. SCANNING MEANS Illumination PROCESSOR ELECTRO-OPTICAL SYSTEM A/D CONVERTOR DATA Reflected Light Definition • Bar Code Reader • A device used to extract the information that is optically encoded in a BCS and convert it into computer-compatible digital data • Two devices: Reader & Decoder (sometimes packaged together as one)

  13. READER FUNCTIONS 1. Find the correct elements 2. Determine the widths of each symbol’s bars and spaces 3. Quantize the element widths into the number of levels appropriate to the symbology used 4. Ensure that the quantized element widths are consistent with all of the encodation rules for the symbology 5. If necessary, reverse the data order 6. Confirm that quiet zones exist 7. Confirm that any check characters are consistent with decoded data

  14. LIGHT SOURCE LIGHT SOURCE PHOTO DETECTOR PHOTO DETECTOR APERTURE APERTURE TRANSMITTING TRANSMITTING RECEIVING RECEIVING LENS LENS LENS LENS SYMBOL SYMBOL Electro-Optical System • Light source creates “spot” on symbol • Reader Captures and measures reflectivity • Bars: Low Reflectivity • Spaces: High Reflectivity (Focused Illuminator Design)

  15. Analog-to-Digital Converter

  16. Symbol Orientation • Picket Fence vs. Ladder

  17. Wavelength • Reflectivity varies at different wavelengths • Wavelength Match between Reader and Symbol • Most Common Bands • 633 nm • 900 nm (infrared)

  18. Specular Reflection • Print symbols on diffuse, non-shiny, matte surface (e.g., paper) • Avoid shiny surfaces (e.g., windows, laminates) Specular Reflection Diffuse Reflection

  19. Specular Reflection SPECULAR REFLECTION

  20. Avoiding Specular Reflection • Do not print on mirrors or shiny surfaces • Scan at an angle (<), not perpendicular to surface ( ) • Quick Test: • Hold symbol at shallow angle; bright reflection from Overhead light?

  21. Bar Code Scanner (Most Commonly Used) Input Devices • Wands • Lasers • CCD • Fixed Mount

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