This study investigates the optimal distribution and pattern of ground control points (GCPs) in aerial photogrammetric projects. Aerial triangulation (AT), also known as bundle adjustment, is the ...fundamental step in refining 3D reconstruction models and camera positions, thereby minimizing reprojection errors. The study utilizes data from a national project in Romania, employing high-resolution aerial images acquisition using photogrammetric sensors. The project has rigorous requirements of ground control points (GCP) placement and field measurements using GNSS and geometric leveling techniques. The study employs various scenarios, manipulating the number and distribution of GCPs, to assess their influence on planimetric and altimetric accuracy. Results indicate that the configuration and number of GCPs significantly affect the accuracy of photogrammetric products, such as dense image point clouds, digital surface models, and orthophotos. Moreover, the study underscores the importance of precise GCP determination methods, especially in regions lacking a precise gravimetric geoid model. In scenarios with inadequate GCP coverage the outcomes have inferior quality, emphasizing the critical role of GCPs in ensuring the quality of photogrammetric products. Overall, the research gives a clear view on the best placement patterns of GCPs and their influence on AT process evaluation performed in check points (CHKs).
Urban Classification from Aerial and Satellite Images Pârvu, Iuliana Maria; Picu, Iuliana Adriana Cuibac; Dragomir, P.I. ...
Journal of Applied Engineering Sciences,
12/2020, Letnik:
10, Številka:
2
Journal Article
Recenzirano
Odprti dostop
When talking about land cover, we need to find a proper way to extract information from aerial or satellite images. In the field of photogrammetry, aerial images are generally acquired by optical ...sensors that deliver images in four bands (red, green, blue and near-infrared). Recent researches in this field demonstrated that for the image classification process is still place for improvement. From satellites are obtained multispectral images with more bands (e.g. Landsat 7/8 has 36 spectral bands). This paper will present the differences between these two types of images and the classification results using support-vector machine and maximum likelihood classifier. For the aerial and the satellite images we used different sets of classification classes and the two methods mentioned above to highlight the importance of choosing the classes and the classification method.
The paper reports some methods to select the optimal number of neighbors and to use eigenfeatures for aerial point cloud classification. In the literature, the neighborhood selection is performed ...using different methods. In this paper, we propose an approach that uses the region growing algorithm. The input data is an aerial point cloud, part of the Romanian Dataset from LAKI II Project. To test our approach, we used a small dataset from the city of Marghita, Bihor County. We report the technical background for classification process and all technical details of the workflow used with insight analyses and comparisons. The work was realized within the VOLTA project (VOLTA, 2017), a RISE Marie-Curie action designed to do research and innovation activities among partners and to exchange knowledge, methods and workflows in the geospatial field.
The VOLTA project is a RISE Marie-Curie action designed to realize Research & Innovation (R&I) among intersectoral partners to exchange knowledge, methods and workflows in the geospatial field. To ...accomplish its objectives, the main R&I activities of VOLTA are divided in four interlinked Work Packages with two transversal ones responsible for knowledge transfer & training as well as dissemination of the project results. The research activities and knowledge transfer are performed with a series of secondments between partners. The consortium is composed of 13 partners from academic & research institutions, industrial partners and national mapping agencies. The Romanian National Center of Cartography is part of this research project and in this article the achievements of the secondment at Bruno Kessler Foundation in Trento (Italy) are given. The main goal of the exchange was to generate level of detail - LOD2 building models in an automated manner from photogrammetric point clouds and without any ancillary data. To benchmark existing commercial solutions for the realization of LOD2 building models, we tested Building Reconstruction. This program generates LOD2 models starting from building footprints, digital terrain model (DTM) and digital surface model (DSM). The presented work examined a research and a commercial-based approach to reconstruct LOD2 building models from point clouds. The full paper will report all technical details of the work with insight analyses and comparisons.
Pixel Based Classification of Images Pârvu, Iuliana Maria; Cuibac - Picu, Iuliana Adriana; Dragomir, Petre Iuliu
RevCAD Journal of Geodesy and Cadastre,
2018
25
Journal Article
Odprti dostop
Nowadays, automation became a basic theme in all the fields of activity. Reducing the operator tasks from a workflow led to the need of research extensions in automation. In Photogrammetry we can ...start this process from the data collection and going to the final product generation. The main goal of this article is to facilitate the updating process of the National Geospatial Database and to ensure support for different products of our institution. The study was conducted on two types of coverage: extraurban and urban areas, both in Bihor County. The segmentation and classification process used the Single Feature Probability method, considering attributes like spectral signature, texture and shape. The results depend on the initial data, the workflow used and the samples collected.
LiDAR Applications Based on LAKI II Project Pârvu, Iuliana Maria; Cuibac - Picu, Iuliana Adriana; Pârvu, Adrian Grigore ...
RevCAD Journal of Geodesy and Cadastre,
2017
23
Journal Article
Odprti dostop
The evolution of technology has led to significant advances enabling the development of precision laser scanning technology. LiDAR technology involves scanning a surface with laser waves. The ability ...to process dense point clouds in an efficient and cost-effective manner has facilitated a multitude of 3D data acquisition applications. This paper presents the ongoing project “Geographical Information for the Environment, Climate Change and EU Integration” LAKI II and some applications derived from it. One of the applications is the flooding risk analysis using LiDAR technology based products. Another application is the fusion of data from different sensors for some historical monuments, like Oradea Fortress. Improving the final products for cities by generating higher resolution digital surface models is one of our future goals.
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