Jakub Szulwic

Maritime Laser Scanning as the Source for Spatial Data

Abstract The rapid development of scanning technology, especially mobile scanning, gives the possibility to collect spatial data coming from maritime measurement platforms and autonomous manned or unmanned vehicles. Presented solution is derived from the mobile scanning. However we should keep in mind that the specificity of laser scanning at sea and processing collected data should be in the form acceptable in Geographical Information Systems, especially typical for the maritime needs. At the same time we should be aware that data coming from maritime mobile scanning constitutes a new approach to the describing of maritime environment and brings a new perspective that is completely different than air and terrestrial scanning. Therefore, the authors, would like to present results of an experiment aimed at testing the possibilities of using mobile scanning at sea. Experiment was conducted in the harbour and the associated environment of neighbouring southern coast of the Baltic Sea.

Mobile Indicators in GIS and GPS Positioning Accuracy in Cities

The publication describes the possible use of tele-geoprocessing as a synergy of modern IT solutions, telecommunications and GIS algorithms. The paper presents a possibility of urban traffic monitoring with the use of mobile GIS indicators of dedicated monitoring system designed for taxi corporation. The system is based on a stationary and mobile software package. The optimal and minimal assumptions for the monitoring of urban traffic are described. They can be implemented as a verification or supplementary tool for complex and high cost transportation management systems or throughput of city streets monitoring systems. The authors show limitations of standard monitoring and GNSS positioning in urban area. They indicate the possible improvement in the functionality of the application to the calculation of supplementary vector data of possible trajectories and based on it, the correction of the data received from the satellite positioning.

System of monitoring of the Forest Opera in Sopot structure and roofing

The authors present a solution realized in Forest Opera (name in Polish: Opera Leśna) in Sopot (Poland) in connection with the modernization and construction of a new roof. The complicated structure of the roof of the facility and the used covering in form of membrane made of technical fabric required (for security reasons) to install the unit of devices allowing for the continuous geodetic monitoring of the facility. Monitoring of relocations in case of engineering structures of a complex design allows for the extended safety of their use. Realized (for this purpose) geodetic measurements require (to be useful) a high accuracy, full automation making the assessment independent from the human factor and the use of reference points. The main element of the presented system is a motorized total station used for the determination of roof cover relocations, whereas the complementary elements are vibration and temperature sensors and weather conditions monitoring station. Data recorders from the entire facility are connected to the computer central unit, providing automation of measurements and archiving of results along with their analysis. The problem occurring in the analyzed object is relatively unstable (subject to vibration) total station. Therefore, the solution implemented for Opera Leśna in Sopot assumes, that it is required to carry out measurements against reference points before every measurement of controlled points. On the basis of these measurements, for each measurement epoch the coordinates and relocation vectors for the tachymeter station are checked as well as analyses of an accuracy suitable for this process. The solution of this problem is useful for monitoring in other movable or subject to relocation engineering facilities. The article signalizes the problem of accuracy of surveying. For this purpose, the preliminary analyses of an accuracy were carried out. They made it possible to determine the expected errors of the reference points location in the designed network geometry and position of the total station for two variants: with and without taking into account the erroneous of reference points location. To summarize, we can say that the automatic measurement systems are an appropriate method for the continuous observation of the construction condition, however, they must be based on accurate, repeatable (for each measurement epoch) analyses of the observation of both monitored elements as well as their spatial references.

AIRBORNE AND MOBILE LASER SCANNING IN MEASUREMENTS OF SEA CLIFFS ON THE SOUTHERN BALTIC

Measurements of sea cliffs performed using periodic surveying based on laser scanning is currently one of the fastest and most accurate solutions. Supported with the technology of satellite measurements using GNSS (Global Navigation Satellite System) positioning and photographic measurements with the use of aerial vehicle, they enable an effective monitoring of the sea cliffs affected by the erosion. In case of the coast of southern Baltic, there are also the cliffs with a low angle of inclination and terraces; additionally there is a restriction concerning an access to the cliff from the shore side because of the narrow or nonexistent lane of the beach. Hence there is a need for synergy of mobile measurements (Maritime Laser Scanning, MarLS) with airborne measurements (LiDAR).

PHOTOGRAMMETRIC DEVELOPMENT OF THE THRESHOLD WATER AT THE DAM ON THE VISTULA RIVER IN WLOCLAWEK FROM UNMANNED AERIAL VEHICLES (UAV)

Barrage in Wloclawek (Poland) was designed by Hydroprojekt and built in the years of 1962-1970 as the first stage of the planned Lower Vistula Cascade. Cascade design assumed the construction of 8 dams in Wyszogrod, Plock, Wloclawek, Nieszawa (Ciechocinek as an option), Solec Kujawski, Chelmno, Opalen and Tczew. Nieszawa dam was supposed to ensure the maintenance of an adequate free surface of water below the right dam in Wloclawek. Lower Vistula Cascade was not built, and until nowadays the dammed role is realized by the water threshold downstream the dam in Wloclawek, in its immediate vicinity. This threshold is a subject of a particular concern and photogrammetric analysis, presented in the article. Technical aspects and condition of the water threshold are related to the stability of the dam on the Vistula River in Wloclawek. Currently, the investment process was launched and it is aimed to change the development of Lower Vistula area. The investment realization is connected with the renovation of the dam on the Vistula River and it should help to change the role of the threshold in Wloclawek. At the same time, the awareness and qualitative evaluation of the threshold are required. Due to the difficulties in access to the threshold and the limited time of its unveiling, the photogrammetric method using Unmanned Aerial Vehicle (UAV) seemed to be effective and available for quick registration and validation of the threshold. The authors present the photogrammetric preparation which reflects the threshold condition. The realization was performed on the basis of 70 non-metric photos taken from the UAV. As part of the article, the technological problems and their solutions related to planning the run-in, as well as the description of the measurement method combining the photogrammetric and geodetic preparations (tachymeter measurement using TotalStation) are cited. The article includes the technical analysis of the enterprise and it indicates methods for the optimization of UAV use in the elaborations related to hydraulic engineering structures.

THE METHOD OF ANALYSIS OF DAMAGE REINFORCED CONCRETE BEAMS USING TERRESTRIAL LASER SCANNING

The authors present an analysis of the possibility to assess deformations and mode of failure of R-C beams using terrestrial laser scanning. As part of experiments carried out at the Regional Laboratory of Construction (at Gdansk University of Technology), reinforced concrete beams were subjected to destruction by bending and by shear. The process of press impact on the reinforced concrete beam was recorded using terrestrial laser scanner. Development of scanning effects was performed using Leica Cyclone software and MeshLab. In order to verify results, the independent recording of beam deflection with use of extensometer and the recording with non-meter synchronous digital cameras were carried out, photos from these cameras were subjected to photogrammetric processing. However, the principal subject of this paper is to show the usefulness of laser scanning for the analysis of reinforced concrete beams damages and authors of this paper focused on this subject. In the description of the experiment there are six stages of measurement mentioned for the reinforced concrete beam: from the zero condition (no force), through intermediate conditions up to the stage of destruction. Scanning was performed from one stable measurement station to avoid in processing the effect of correlation errors (matching and linking) of ScanWorld. Analysis of the materials from laser scanning allowed to assess the geometry of element subjected to destruction with an accuracy not worse than 1 mm. For this purpose, the method of spheres translation was developed and in its characteristic groups of points from scanning the spheres were described. Spheres centers grew to be geometrical element to be assessed on scans in subsequent measurement epochs. Additionally, through the use of automated analysis of intensity map of laser light reflection, it was indicated the possibility of rapid identification of the beam, in which there may occur microcracks and changes in the structure. The usefulness of the evaluation mechanism can be appreciated in the mass studies or inspective examinations of constructional components. As a result of the authors’ research and in the course of measurements analysis it was possible to establish the concise procedure to specify the mode of the reinforced concrete destruction and it was defined the minimum size of cracks that may be recorded in the cloud of points from laser scanning.

A METHOD OF SELECTING LIGHT SOURCES FROM NIGHT SATELLITE SCENES

ABSTRACT Satellite images carries a lot of data. Very sophisticated methods of analyses may reveal very complicated nature of the observed objects. In case of night images, lights play the role of information sources. In this paper we would like to present results of the research aimed to describe light sources from satellite night images by providing description of their luminosity. The authors point source imaging data from the satellite systems available for use in the remote sensing analyses. They also present researches on the analysis of light propagation based on measurements of radiance of night city lights on the basis of modern satellite imaging systems and models of light propagation in the atmosphere. The paper includes a description of the technology of satellite scenes remote sense analysis with successive steps of the creation of night lighting map. The purpose of the article, in addition to the presentation of the current scientific achievements, based on the night satellite images showing the potential of this technology, is an attempt to draw attention to the problem of light pollution and to make a simple analysis of this phenomenon on the basis of such imaging.

A modern approach to an unmanned vehicle navigation

A traditional approach to manned vehicles navigation uses a data combined form a variety of navigation sensors like satellite, inertial and time-of-flight. With support of operators perception, chart and sensor, data are analyzed and navigation decisions are made. An unmanned platforms navigation needs an operators support, who is supervising a platforms decision process, basing on navigation data obtained via variety of electronic sensors. Majority of unnamed platform are equipped with a single visible light camera, in order to transmit an actual information on platforms surroundings. It helps operator to react on dynamically changing navigation situation. That fact lead us to a thesis, that a visual data generated by a single nonmetric camera can be a good source of navigation information for plotting own platform trajectory and support an autonomous navigation process.

An unorthodox view on the problem of tracking facial expressions

Recent developments in imaging cameras has opened a new way of analyzing facial expression. We would like to take advantage from this new technology and present a method of imaging and processing images of human face as a response to the particular stimuli. The response in this case is represented by the facial expressions and the stimuli are still images representing six basic emotions according to Eckmann. Working hypothesis of presented research, states that the new method of tracking facial expressions is more precise and distinctive enough to give characteristic description of the analyzed human face. The biggest advantage of the presented method, in the opinion of research team, is the fact that it uses remote sensing techniques and presents dynamics of the changes happening on the human face. Therefore, FMRI might not be required, which decreases the costs of experiments, additionally, method is less stressful for the examined persons and provides more natural reactions.

3D MODELLING OF CYLINDRICAL-SHAPED OBJECTS FROM LIDAR DATA - AN ASSESSMENT BASED ON THEORETICAL MODELLING AND EXPERIMENTAL DATA

Despite the increasing availability of measured laser scanning data and their widespread use, there is still the problem of rapid and correct numerical interpretation of results. This is due to the large number of observations that carry similar information. Therefore, it is necessary to extract from the results only the essential features of the modelled objects. Usually, it is based on a process using filtration, followed by simplification and generalization of redundant contents of datasets. This process must ensure the collection of new data without loss of information contained therein, the description accuracy of the key features of a measured object, as well as the uniqueness and comparability of results. In this paper, the authors extend the already extensive range of algorithms for the automatic or semiautomatic modelling of cylindrical objects, which have been measured using the laser scanning technology, with the one employing a concave hull or-in general-the alpha-shape (α-shape). The applicability of the proposed method was analysed using simulated data-generated analytically with the introduced and established systematic error with normal distribution-and using real results of the measurement of cylindrical-shaped objects. For real data, the obtained results were compared with the reference data. This made it possible to determine the validity of the proposed new method.