Current available shape measurements

imea supports the extraction of 2D and 3D shape measurements from images.

2D shape measurements

Currently, 53 twodimensional shape measurements are implemented in imea, as shown below. According to DIN ISO 9276-6 these are structured in macro-, meso- and microdecriptors as well as statistical lengths, as illustrated below.

Macro decriptors (imea.measure_2d.macro)

Macrodescriptors represent the overall, external shape of a particle. The following macrodescriptors are currently available in imea:

• Perimeter
  • perimeter
  • convex_perimeter
• Area
  • area_projection
  • area_filled
  • area_convex
• Legendre inertia ellipse
  • major_axis_length
  • minor_axis_length
• Diameters
  • diameter_max_inclosing_circle
  • diameter_min_enclosing_circle
  • diameter_circumscribing_circle
  • diameter_inscribing_circle
  • diameter_equal_area
  • diameter_equal_perimeter
• Max dimensions
  • x_max
  • y_max
• Minimal bounding box
  • width_min_bb
  • length_min_bb
• Geodetic length and thickness
  • geodeticlength
  • thickness

Meso decriptors (imea.measure_2d.meso)

Mesodescriptors describe details in the particle shape and/or surface structure whose magnitude are not much smaller than the particle proportions. The following mesodescriptors are currently available in imea:

• n_erosions
• n_erosions_complement

Micro decriptors (imea.measure_2d.micro)

Microdescriptors describe the roughness of particle contours. The following microdescriptors are currently available in imea:

• fractal_dimension_boxcounting_method
• fractal_dimension_perimeter_method

Statistical lengths (imea.measure_2d.statistical_length)

Statistical lengths are macrodescriptors that are evaluated at different rotation angles of the shape. Based on the resulting distribution of statistical length different metrics like the minimum or maximum value can be obtained. The following statistical length are currently available in imea:

• Feret diameter
  • feret_max
  • feret_min
  • feret_median
  • feret_mean
  • feret_mode
  • feret_std
• Martin diameter
  • martin_max
  • martin_min
  • martin_median
  • martin_mean
  • martin_mode
  • martin_std
• Nassenstein diameter
  • nassenstein_max
  • nassenstein_min
  • nassenstein_median
  • nassenstein_mean
  • nassenstein_mode
  • nassenstein_std
• Max chords
  • maxchords_max
  • maxchords_min
  • maxchords_median
  • maxchords_mean
  • maxchords_mode
  • maxchords_std
• All chords
  • allchords_max
  • allchords_min
  • allchords_median
  • allchords_mean
  • allchords_mode
  • allchords_std

More information on the implementation and references can be find in the imea repository.

3D shape measurements

For 3D recordings, there are 13 threedimensional shape measurements implemented in imea:

Macro decriptors (imea.measure_2d.macro)

• Volume and surface area
  • volume
  • volume_convexhull
  • surface_area
• Diameter
  • diameter_volume_equivalent
  • diameter_surfacearea_equivalent
• Minimal 3D bounding box
  • width_3d_bb
  • length_3d_bb
  • height_3d_bb
• Feret diameter (3D)
  • feret_3d_max
  • feret_3d_min
• Max dimensions (3D)
  • x_max_3d
  • y_max_3d
  • z_max_3d

To our best knownledge there are currently no 3D meso and microdecriptors proposed or used in scientific literature or technical norms. If you found any: Please submit an issue with link to the paper where they are proposed and used (see also our guidelines on contribution), so we can integrate them into imea in the future.

More information on the implementation and references can be find in the imea repository.