Field evaluation of Pix4D viDoc for retaining wall inspections

Abstract

Reliably accurate documentation of retaining wall conditions is necessary for managing long-term infrastructure health and maintaining public safety. Current visual inspection practices lack the precision and consistency needed to detect early signs of change in a structure. This technical note evaluates the Pix4D viDoc as a practical tool to supplement routine retaining wall inspections with detailed three-dimensional (3D) models that enhance asset management programs. The viDoc was tested on three retaining walls with various surfaces and site conditions that exemplified the variability of retaining walls in the field. Ground truth reference data was collected using a terrestrial laser scanner (TLS). Results showcase the viDoc’s potential for efficient on-site operation that yields centimetre-level accuracy under favourable conditions. Limitations on sites with dense vegetation, accessibility constraints, and poor global navigation satellite system signal quality were observed. Overall findings support the viDoc’s use as a cost-effective alternative to TLS for supplemental 3D imaging of retaining walls during routine inspections.