Dual-mode laser elevation measurement and vibration compensation for concrete finished surfaces

Abstract

To address the difficulty of obtaining continuous elevation information from large-area concrete finished surfaces during construction, together with the degradation of measurement stability caused by on-site vibration, this study presents a dual-mode laser elevation measurement method for concrete finished surfaces. The proposed workflow integrates phase-based ranging, laser triangulation, multi-distance calibration, static uncertainty evaluation, and vibration compensation within a unified measurement chain. The phase channel is used for working-distance identification and short-range absolute ranging, whereas the triangulation channel is used for medium-range elevation inversion after multi-distance offline calibration. To improve spot-center robustness under heterogeneous concrete reflectance, a partitioned weighted-centroid method is adopted. A static uncertainty evaluation is then performed for the triangulation-based elevation output, and an adaptive compensation link driven by vertical acceleration is introduced to suppress dominant narrowband vibration. Over the calibration range of 5–28 m, the fitted models yield R2 values of 0.8763–0.9999 and root mean square error (RMSE) values of 0.0516–1.9911 mm. Within the recommended working range of 5–25 m, the mean R2 and RMSE are 0.9952 and 0.344 mm, respectively. Static validation at four representative distances gives RMSE values of 0.1285–0.5866 mm, and the expanded uncertainty at L = 5 m is 0.3246 mm (k = 2). Under a dominant vibration frequency of 6.35 Hz, the de-meaned displacement RMS is reduced from 0.4028 mm to 0.1330 mm after compensation. A concrete panel-joint experiment further shows that the method can recover the overall undulation and local protrusion characteristics of the test surface. These results demonstrate the feasibility of the proposed method for automated elevation measurement under representative construction conditions.