Accurate 3D Shape, Displacement and Deformation Measurement Using a Smartphone

Area of Science:

• Experimental Mechanics
• Optical Measurement Techniques
• Instrumentation

Background:

• Stereo-digital image correlation (DIC) is vital for 3D measurements but requires expensive equipment.
• Existing DIC setups are bulky and complex, limiting use in resource-limited or field settings.

Purpose of the Study:

• To develop a cost-effective, ultra-portable smartphone-based stereo-DIC system.
• To explore the capabilities and limitations of this novel configuration for 3D measurements.

Main Methods:

• Utilized a smartphone with a custom optical attachment featuring four planar mirrors to simulate stereovision.
• Validated the system through 3D shape, in-plane/out-of-plane displacement, and strain measurements on composite specimens.
• Investigated and explained thermal-induced errors caused by smartphone heating.

Main Results:

• The system accurately measured 3D shape and displacement after addressing thermal errors via preheating.
• Strain measurements on a composite specimen showed comparable accuracy to traditional strain gauges.
• Successfully demonstrated 3D deformation tracking on a deflating ball.

Conclusions:

• The smartphone-based stereo-DIC system provides a viable, low-cost alternative for 3D deformation analysis.
• Its portability and reduced cost enhance accessibility for scientific research and field applications.
• Further research can optimize the system to mitigate thermal effects for even greater accuracy.