Detection of Bricks in a Masonry Wall

Laser scanning is being increasingly applied in the documentation of buildings and archaeological sites. The documentation process sometimes involves making an inventory of bricks in walls. This paper proposes an automatic/semi-automatic segmentation method for detecting bricks in walls, in particular masonry walls. In developing the detection method the problems with detecting bricks in a 3D point cloud obtained by terrestrial laser scanning are first examined. The method starts with a 3D triangulation of a 3D point cloud obtained by terrestrial laser scanning. Associated with each point in the cloud are reflectance values and an RGB triplet. The method then uses the triangulation, reflectance and RGB triplets to effect a proximity-based segmentation. A technique for selecting ideal segmentation parameters is also proposed. The method is tested on the point cloud of three different walls and the results of the brick detection are presented. Early results are promising.