Formtraits

Formtraits is a term used in data analysis to denote a concise set of quantitative properties that capture the form of an object. A formtrait describes aspects of shape and outline, size, and spatial relationships between parts, enabling comparisons across instances. They are used across disciplines to quantify morphology and to support algorithmic matching, classification, or retrieval tasks.

Extraction and representation: Formtraits may be derived from 2D images, 3D meshes, or procedural models. Common approaches include contour-based features such as curvature, Fourier descriptors, and eccentricity; boundary moments such as Hu moments; and local descriptors such as curvature scale space. In 3D, surface-based measures like Gaussian curvature and shape index are included. Formtraits are often made invariant to translation, rotation, and scale through normalization.

Applications: In computer vision and pattern recognition, formtraits enable shape matching and object identification. In biology and paleontology, formtraits quantify leaf or shell shapes for classification. In computer-aided design, formtraits describe form families and support parametric modeling. They are also used in quality control to detect deviations from nominal form.

Limitations and scope: Reliance on sampling density, noise, and occlusion can affect reliability. Interpreting formtraits requires domain context to avoid overgeneralization, as different forms may share similar traits. The term is often used descriptively, with many domain-specific variants and vocabularies.

See also: shape descriptor, geometric features, contour analysis.