From Elevation Maps To Contour Lines: SVM and Decision Trees to Detect Violin Width Reduction

arXiv cs.AI / 4/6/2026

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Key Points

  • The study investigates automatic detection of violin width reduction using 3D photogrammetric meshes as the underlying data source.
  • It compares two machine-learning approaches—SVM and Decision Trees—fed by either a raw geometry representation derived from elevation maps or a feature-engineered representation based on fitted parametric contour lines.
  • While elevation-map-based inputs sometimes produce strong performance, they generally fail to outperform the contour-based, targeted features.
  • The results suggest that contour-line fitting provides a more effective geometric signal for this specific shape-change detection task than more generic elevation-map representations.

Abstract

We explore the automatic detection of violin width reduction using 3D photogrammetric meshes. We compare SVM and Decision Trees applied to a geometry-based raw representation built from elevation maps with a more targeted, feature-engineered approach relying on parametric contour lines fitting. Although elevation maps occasionally achieve strong results, their performance does not surpass that of the contour-based inputs.