Scratch Parameters

How scratches are detected

  • Scratches are detected using a high‑intensity 10° spot light that illuminates the surface in a very directional way, similar to shining an inspection torch across a panel to reveal fine marks.
  • An observer camera captures a high‑resolution image of the illuminated area, and image‑processing algorithms analyse the bright, elongated features caused by light catching on scratch edges.

Role of sensitivity

  • The Sensitivity setting controls how aggressively the system looks for scratches by adjusting detection thresholds in the image analysis.
  • At low sensitivity, only the more obvious scratches are reported, corresponding to defects that are easily visible under typical indoor or workshop lighting.
  • At medium sensitivity, the system reveals finer swirls and lighter polishing marks that may be visible under stronger point light sources, for example inspection lamps or showroom lighting.
  • At the highest sensitivity, the algorithm highlights almost all detectable line structures, including very faint scratches and holograms that may only become visible under high illuminance conditions, such as bright sunshine or intense inspection lighting.

Length, Length V and Length H

  • Length – Scratch Length Total Average (µm): The average total length of all detected scratches within the measured area, giving an overall indication of how extensive linear defects are on the surface.
  • Length V – Scratch Length Average Vertical (µm): The average total length of scratches predominantly aligned in the vertical direction, useful for identifying directionality from specific polishing passes or tools.
  • Length H – Scratch Length Average Horizontal (µm): The average total length of scratches predominantly aligned in the horizontal direction, highlighting directional polishing patterns.

Area, Area V and Area H

  • Area – Total Scratched Area (µm²): The combined surface area covered by all detected scratches, indicating how much of the inspected region is affected by polishing defects.
  • Area V – Scratched Area Vertical (µm²): The total area occupied by vertically oriented scratches, helping to separate their contribution from other defect directions.
  • Area H – Scratched Area Horizontal (µm²): The total area occupied by horizontally oriented scratches, useful when diagnosing process steps that introduce specific directional marks.

Count, Count V and Count H

  • Count – Total Scratches (–): The number of individual scratches detected in the measurement, giving a simple measure of how densely the surface is covered with defects.
  • Count V – Scratches Vertical (–): The number of vertically oriented scratches, used to identify and track polishing steps that introduce mainly vertical marks.
  • Count H – Scratches Horizontal (–): The number of horizontally oriented scratches, indicating the prevalence of defects aligned with horizontal polishing movements.

Visibility, Visibility V and Visibility H

  • Visibility – Scratch Visibility Average (AU): The average perceived visibility of all detected scratches, combining their brightness, contrast and size into a single perception‑based value.
  • Visibility V – Scratch Visibility Vertical (AU): The perceived visibility of vertically oriented scratches, highlighting whether vertical marks are particularly noticeable to the observer.
  • Visibility H – Scratch Visibility Horizontal (AU): The perceived visibility of horizontally oriented scratches, allowing judgement of whether horizontal swirls or holograms dominate the visual impression.