AUTOMATION OF WINDOWS DETECTION FROM GEOMETRIC AND RADIOMETRIC INFORMATION OF POINT CLOUDS IN A SCAN-TO-BIM PROCESS
Keywords: point cloud, geometry, colour, intensity, automation, windows detection, as-built BIM
Abstract. The detection of openings based on point clouds is generally based on geometric features namely the X, Y and Z coordinates of points. Existing methods exploit geometric features but ignore most of the time other attributes as colour and intensity. Such information may be however particularly interesting to recognise and segment openings in facades. In this paper, the use of radiometric information, namely colour and intensity, is investigated for the segmentation of windows from façade point clouds. The assumption is made that windows are significantly different in terms of materials and colours to be distinguished from facade walls. The exploitation of colour and intensity are considered separately. A histogram analysis method is proposed for the exploitation of intensity information whereas a region growing method based on colorimetric distances is considered for the exploitation of colours. In order to refine the results, geometric information, and more precisely depth of points with regards to façade walls, are combined to radiometric information. Several combinations of attributes are considered and provide promising results for windows segmentation based on point clouds.