Volumetric Analysis using Graphic Double Integration
Measure and analyze cross-sectional geometry supplied as an image.
Calculates the second moment of area (=area moment of inertia, Ix and ...
Estimate soft tissue expansion factors following Macaulay et al. 2023
Tool to help determine which threshold value and method to use with me...
Estimate volume using Graphic Double Integration.
Finds the horizontal (x axis, i.e. the axis vertical to the cross-sect...
Simple histogram analysis for all color values in an input image. Can ...
Helper function for interpolating cross-sectional metrics over the len...
Take pixel-by-pixel measurements of a silhouette in jpeg or png format...
Plots a silhouette read by measuresil()
Calculates the rotational inertia of a body. Only works with simple ci...
calculate coordinates for plotting a superellipse for visualizing body...
Estimate area of a superellipse. Assistant function for gdi.
Transfer a vector of aspect ratios onto another body profile
Finds the vertical (y axis, i.e. the axis parallel to the cross-sectio...
Tools implementing an automated version of the graphic double integration technique (GDI) for volume implementation, and some other related utilities for paleontological image-analysis. GDI was first employed by Jerison (1973) <ISBN:9780323141086> and Hurlburt (1999) <doi:10.1080/02724634.1999.10011145> and is primarily used for volume or mass estimation of (extinct) animals. The package 'gdi' aims to make this technique as convenient and versatile as possible. The core functions of 'gdi' provide utilities for automatically measuring diameters from digital silhouettes provided as image files and calculating volume via graphic double integration with simple elliptical, superelliptical (following Motani 2001 <doi:10.1666/0094-8373(2001)027%3C0735:EBMFST%3E2.0.CO;2>) or complex cross-sectional geometries (see also Zhao 2024 <doi:10.7717/peerj.17479>). Additionally, the package provides functions for estimating the center of mass position (COM), the moment of inertia (I) for 3D shapes and the second moment of area (Ix, Iy, Iz) of 2D cross-sections, as well as for the visualization of results.