Measurement methodology for surface defects inventory of building wall using smartphone with light detection and ranging sensor

The popularity of smartphones along with advances in sensor technologies has opened new possibilities for scientific application and low-cost observation. Particularly useful is the LiDAR sensor, which can be used to measure building elements. The aim of study is to propose a new methodology of using the smartphone with LiDAR Apple iPhone XR, in examining wall cracks and resulting displacement. Due to the fact, that the measured walls were quasi-flat and homogeneous, dedicated spatial measurement targets (SMTs) were used for measurement. These SMTs are designed to change the geometry of the tested object. The methodology proposed in the study includes measurements using a smartphone with LiDAR in variants with and without SMTs, and its analysis. The test results are compared with the measurements using a terrestrial laser scanner (TLS). Analysis showed that for detecting small cracks such as 0.5-1.0 mm, smartphone measurement with LiDAR and SMT is better than TLS.