This paper discusses the issue of automation of orthoimage generation based on Terrestrial Laser Scanning (TLS) data and digital images. The following two problems are discussed: automatic generation of projection planes based on TLS data, and automatic orientation of digital images in relation to TLS data. The majority of popular software applications use manual definitions of projection planes. However, the authors propose an original software tool to address the first issue, which defines important planes based on a TLS point cloud utilizing different algorithms (RANdom SAmple Consensus-RANSAC, Hough transform, "region growing"). To address the second task, the authors present a series of algorithms for automated digital image orientation in relation to a point cloud. This is important in cases where scans and images are acquired from different places and at different times. The algorithms utilize Scale Invariant Feature Transform(SIFT) operators in order to find points that correspond in reflectance intensity between coloure images (Red Green Blue-RGB) and orthoimages, based on TLS data. The paper also presents a verification method using SIFT and Speeded-Up Robust Features (SURF) operators. The research results in an original tool and applied Computer Vision(CV) algorithms that improve the process of orthoimage generation.

Commission IIKEY WORDS: cultural heritage, tower verticality, structure from motion (SFM), multi-view stereo (MVS), terrestrial laser scanning (TLS), UAV ABSTRACT:This paper presents an analysis of source photogrammetric data in relation to the examination of verticality in a monumental tower. In the proposed data processing methodology, the geometric quality of the point clouds relating to the monumental tower of the castle in Iłżawas established by using terrestrial laser scanning (Z+F 5006h, Leica C10), terrestrial photographs and digital images sourced via unmanned aerial vehicles (UAV) (Leica Aibot X6 Hexacopter). Tests were performed using the original software, developed by the authors, which allows for the automation of 3D point cloud processing. The software also facilitates the verification of the verticality of the tower and the assessment of the quality of utilized data.

ABSTRACT:At present, digital documentation recorded in the form of raster or vector files is the obligatory way of inventorying historical objects. The orthoimage is a cartometric form of photographic presentation of information in the two-dimensional reference system. The paper will discuss the issue of automation of the orthoimage generation basing on the TLS data and digital images. At present attempts are made to apply modern technologies not only for the needs of surveys, but also during the data processing. This paper will present attempts aiming at utilisation of appropriate algorithms and the author's application for automatic generation of the projection plane, for the needs of acquisition of intensity orthoimages from the TLS data. Such planes are defined manually in the majority of popular TLS data processing applications. A separate issue related to the RGB image generation is the orientation of digital images in relation to scans. It is important, in particular in such cases when scans and photographs are not taken simultaneously. This paper will present experiments concerning the utilisation of the SIFT algorithm for automatic matching of intensity orthoimages of the intensity and digital (RGB) photographs. Satisfactory results of the process of automation, as well as in relation to the quality of resulting orthoimages have been obtained.

ABSTRACT:Updating the cadastre requires much work carried out by surveying companies in countries that have still not solved the problem of updating the cadastral data. In terms of the required precision, these works are among the most accurate. This raises the question: to what extent may modern digital photogrammetric methods be useful in this process? The capabilities of photogrammetry have increased significantly after the introduction of digital aerial cameras and digital technologies. For the registration of cadastral objects, i.e., land parcels' boundaries and the outlines of buildings, very high-resolution aerial photographs can be used. The paper relates an attempt to use an alternative source of data for this task -the development of images acquired from UAS platforms. Multivariate mapping of cadastral parcels was implemented to determine the scope of the suitability of low altitude photos for the cadastre. In this study, images obtained from UAS with the GSD of 3 cm were collected for an area of a few square kilometres. Bundle adjustment of these data was processed with sub-pixel accuracy. This led to photogrammetric measurements being carried out and the provision of an orthophotomap (orthogonalized with a digital surface model from dense image matching of UAS images). Geometric data related to buildings were collected with two methods: stereoscopic and multi-photo measurements. Data related to parcels' boundaries were measured with monoplotting on an orthophotomap from low-altitude images. As reference field surveying data were used. The paper shows the potential and limits of the use of UAS in a process of updating cadastral data. It also gives recommendations when performing photogrammetric missions and presents the possible accuracy of this type of work.