Measuring digit lengths with 3D digital stereophotogrammetry: A comparison across methods. A Gremba, SM Weinberg.

Date: July/August 2018.
Source: American Journal of Human Biology, Volume 30, Issue 4.
Objective: We compared digital 3D stereophotogrammetry to more traditional measurement methods (direct anthropometry and 2D scanning) to capture digit lengths and ratios.
Methods: The length of the second and fourth digits was measured by each method and the second‐to‐fourth ratio was calculated. For each digit measurement, intraobserver agreement was calculated for each of the three collection methods. Further, measurements from the three methods were compared directly to one another. Agreement statistics included the intraclass correlation coefficient (ICC) and technical error of measurement (TEM).
Results: Intraobserver agreement statistics for the digit length measurements were high for all three methods; ICC values exceeded 0.97 and TEM values were below 1 mm. For digit ratio, intraobserver agreement was also acceptable for all methods, with direct anthropometry exhibiting lower agreement (ICC = 0.87) compared to indirect methods. For the comparison across methods, the overall agreement was high for digit length measurements (ICC values ranging from 0.93 to 0.98; TEM values below 2 mm). For digit ratios, high agreement was observed between the two indirect methods (ICC = 0.93), whereas indirect methods showed lower agreement when compared to direct anthropometry (ICC < 0.75).
Conclusions: Digit measurements and derived ratios from 3D stereophotogrammetry showed high intraobserver agreement (similar to more traditional methods) suggesting that landmarks could be placed reliably on 3D hand surface images. While digit length measurements were found to be comparable across all three methods, ratios derived from direct anthropometry tended to be higher than those calculated indirectly from 2D or 3D images.

Article: Measuring digit lengths with 3D digital stereophotogrammetry: A comparison across methods.
Authors: Allison Gremba, Seth M Weinberg, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.