The invention relates to the technical field of optical measurement, in particular to a
laser-based building
engineering flatness measurement method and
system, and the method comprises the following steps: obtaining
point cloud data through three-dimensional
laser scanning, dividing grids, removing low-density units, carrying out the statistics of a
reflectivity mean value and a variable coefficient, extracting a normal main direction, and generating optical features; and constructing a weighted
linear model to correct a classification threshold, performing density clustering analysis based on the corrected threshold, calculating height range and normal deviation distribution, outputting flatness and gradient indexes, and generating a construction
surface flatness evaluation result. According to the method, through combination of three-dimensional
laser scanning and
point cloud density screening, a multi-dimensional optical
feature vector is constructed, a classification threshold value is dynamically corrected through
weight distribution, a normal and a height feature are integrated through density clustering, a regional collaborative index is constructed, matching performance and evaluation precision are enhanced, and construction
surface flatness continuity, data relevance and deformation capture precision are improved.