Análise qualidade de escaneamento 3D fotogramétrico de baixo custo

Abstract

Three-dimensional digitization has become a useful tool in reverse engineering, geometric documentation, and computer-aided inspection workflows. However, the technical value of a reconstructed model depends not only on visual realism, but also on its ability to preserve dimensions and shapes with sufficient stability for the intended application. In this context, the present study evaluated the dimensional quality of a low-cost photogrammetric workflow processed in Agisoft Metashape Standard and geometrically analyzed in Siemens NX, using repeated physical measurements of a test specimen with twelve nominal 10 mm holes as reference. The results showed systematic underestimation of all evaluated holes, with a mean signed error of −2,136 mm, mean absolute error of 2,136 mm, mean absolute relative error of 21,55 %, and digital dispersion substantially higher than physical dispersion. The mean standard deviation of digital measurements was approximately 29,8 times higher than that of physical measurements. The range of digital hole means was artificially amplified relative to the physical dataset, indicating loss of relative fidelity between nominally similar features. The results support that the evaluated workflow is sufficient for macro-geometry representation and conceptual reverse engineering, but unsuitable, as implemented, for dimensional inspection of internal 10 mm holes. The causes discussed throughout the text, such as texture limitations, geometric occlusion, mesh smoothing and geometric fitting sensitivity, are treated as technically plausible interpretations in light of the experimental results and the consulted literature.