Comparison of point clouds produced from close-range photogrammetry and laser scanning techniques

The currently the point clouds are the most preferred data type in diverse engineering projects and applications. The absence of detailed drawing operations is one of the most important factors for this demand. Additionally, the point cloud data in different formats can be used in different software without loss of data. The most common method to produce point cloud is to use laser scanners. These instruments produce 3D point cloud at regular intervals. However, point clouds can be produced with the help of photographs taken in appropriate conditions depending on the developing software and hardware technology. Today, it has become quite easy and many photogrammetric software provide the generation of point cloud support. In this study, whether or not point cloud produced by photographs can be used instead of point cloud produced by laser scanner device is investigated. In accordance with this purpose, rock surfaces which have complex and irregular shape located in Istanbul Technical University Ayazaga Campus were selected as study object. Study object is mixture of different rock types and consists of both partly weathered and fresh parts. Study was performed on a part of 30m x 10m rock surface. 2D and 3D analysis were performed for several regions selected from the point clouds of the surface models. 2D analysis is area-based and 3D analysis is volume-based. Analysis conclusions showed that point clouds in both are similar and can be used as alternative to each other. This proved that point cloud produced using photographs which are both economical and enables to produce data in less time can be used in several studies instead of point cloud produced by laser scanner.