ISO/IEC 29158:2020 PDF

Overview - ISO/IEC 29158:2020 (Direct Part Mark Quality Guideline)

ISO/IEC 29158:2020 is an engineering guideline for assessing the image-based quality of Direct Part Mark (DPM) symbols captured by two-dimensional imagers. Intended primarily for verifier manufacturers and application specification developers, it adapts the symbol quality methodology in ISO/IEC 15415 to address the unique optical and surface characteristics of DPM marks (e.g., dot peen, laser, ink‑jet, electro‑chemical etch). The standard defines alternative illumination conditions, new terms and parameters, modified measurement and grading methods, and reporting conventions - producing a DPM grade rather than an ISO/IEC 15415 grade.

Key Technical Topics and Requirements

• Scope & Purpose
  • Engineering guidance for imaging-based verification of marks applied directly to part surfaces.
  • Predictive of scanner performance in DPM environments where specular reflection and disconnected dots occur.
• Methodology Changes from ISO/IEC 15415
  • Modified measurement and grading routines tailored for DPM symbol characteristics.
  • Reporting of results as a DPM grade.
• Lighting and Camera Configurations
  • Defines multiple illumination setups: perpendicular coaxial (90°), diffuse off‑axis (D), directional lighting patterns (four-, two-, one‑direction), and tilted coaxial lighting (TCL) with tilted camera positions to manage specular highlights.
• Image Acquisition and Optimization
  • Procedures for camera position, focus, depth of field, system response adjustment, and reflectance calibration.
• Quality Metrics and Grading
  • Parameters and grading processes include cell contrast (CC), cell module modulation (CM / CMOD), minimum reflectance (Rmin), and fixed pattern damage (FPD).
  • Inclusion of continuous grading and expanded grading levels for minimum reflectance.
• Verification Workflow
  • Steps to obtain test images, apply a reference decode algorithm, compute reflectance histograms, and produce reproducible grading reports.

Practical Applications and Who Uses It

• Primary users:
  • Verifier manufacturers implementing DPM-capable quality tools.
  • Application specification developers who define acceptance criteria for DPM in production and inspection processes.
  • Systems integrators and quality engineers deploying DPM scanning solutions.
• Practical uses:
  • Standardizing verification of DPM Data Matrix and other matrix symbologies when marks are directly applied to part surfaces.
  • Ensuring consistent verifier behavior in mixed scanning environments (DPM and non‑DPM).
  • Informing imaging hardware selection, lighting design, and acceptance thresholds for manufacturing inspection.

Related Standards

• ISO/IEC 15415 - Matrix symbology print quality methodology (baseline referenced and modified by ISO/IEC 29158).
• ISO/IEC TR 29158:2011 - Earlier technical report superseded by this first edition (ISO/IEC 29158:2020).

Keywords: ISO/IEC 29158:2020, Direct Part Mark, DPM quality guideline, DPM grade, verifier manufacturers, two-dimensional imager, tilted coaxial lighting, ISO/IEC 15415, cell contrast, minimum reflectance.