Comparative analysis of measurement discrepancy and reliability between direct and scanner-based methods in hand...

Area of Science:

• Anthropometry
• Ergonomics
• Biomechanical Engineering

Background:

• Accurate hand anthropometry is crucial for ergonomics, product design, medical applications, and occupational safety.
• Direct caliper measurement (DM) is time-consuming and operator-dependent.
• Two-dimensional flatbed scanning (SC) is a potential faster alternative, but its accuracy for small hand landmarks is uncertain.

Purpose of the Study:

• To compare the accuracy and time efficiency of SC against DM for hand anthropometry.
• To quantify between-method agreement and identify limitations of SC for specific hand dimensions.

Main Methods:

• 56 hand dimensions were measured on 40 Thai adults using both DM and SC.
• Agreement was assessed using mean absolute error (MAE), technical error of measurement (TEM), relative TEM (%TEM), and coefficient of reliability (R).
• Time efficiency was evaluated by measuring technician and participant handling times.

Main Results:

• SC met pre-specified accuracy criteria for 75% of the 56 dimensions.
• High agreement and repeatability were observed for lengths and general breadths (%TEM < 1.5%, R > 0.95).
• Smaller features, especially finger-joint breadths under 25 mm, showed higher errors and lower reliability (%TEM 2.25-4.90%, R < 0.80).
• SC significantly reduced technician time (30.85 min to 14.10 min) and participant handling time (∼2.10 min).

Conclusions:

• SC is a suitable rapid, low-burden method for most hand anthropometric measurements.
• Refined protocols are necessary for sub-25-mm landmarks to enhance precision.
• Improved SC protocols will strengthen population-specific anthropometric databases.