The contribution presents a novel approach to the detection and tracking of lanes based on lidar data. Therefore, we use the distance and reflectivity data coming from a one-dimensional sensor. After having detected the lane through a temporal fusion algorithm, we register the lidar data in a world-fixed coordinate system. To this end, we also incorporate the data coming from an inertial measurement unit and a differential global positioning system. After that stage, an original image of the road can be inferred. Based on this data view, we are able to track the lane either with a Kalman filter or by using a polynomial approximation for the underlying lane model.
New measurement technologies, e.g. Light Detection And Ranging (LiDAR), generate very large datasets. In many cases, it is reasonable to reduce the number of measuring points, but in such a way that the datasets after reduction satisfy specific optimization criteria. For this purpose the Optimum Dataset (OptD) method proposed in [1] and [2] can be applied. The OptD method with the use of several optimization criteria is called OptD-multi and it gives several acceptable solutions. The paper presents methods of selecting one best solution based on the assumptions of two selected numerical optimization methods: the weighted sum method and the "-constraint method. The research was carried out on two measurement datasets from Airborne Laser Scanning (ALS) and Mobile Laser Scanning (MLS). The analysis have shown that it is possible to use numerical optimization methods (often used in construction) to obtain the LiDAR data. Both methods gave different results, they are determined by initially adopted assumptions and – in relation to early made findings, these results can be used instead of the original dataset for various studies.
Terrestrial laser scanning (TLS) is one of the instruments for remote detection of damage of structures (cavities, cracks) which is successfully used to assess technical conditions of building objects. Most of the point clouds analysis from TLS relies only on spatial information (3D–XYZ). This study presents an approach based on using the intensity value as an additional element of information in diagnosing technical conditions of architectural structures. The research has been carried out in laboratory and field conditions. Its results show that the coefficient of laser beam reflectance in TLS can be used as a supplementary source of information to improve detection of defects in constructional objects.
A complete system of a Laser Radar is described in this paper. One explains the principles of the laser and all additional devices used in this system in order to obtain a compact and eye-safe system. The principle and realization of algorithms for controlling the cruise and speed of the vehicle are described. By applying modal control, and choosing the optimal mode for reducing the speed, one derives the system equation and determines its coefficients. Finally, the paper presents simulations of the laser scanning system, the modal control system and the behavior of the system affected by different errors and disturbances. The effects of instrumental errors are defined and simulation is performed illustrating how such a control system is influenced by internal and external disturbances.
In this brief article five bronze fibulae, being exposed in the museum of Şanlıurfa and belonging to the Iron Age, will be presented. At least two of these five were found at Lidar Höyük.
Based on the analysis of the LIDAR terrain Digital Elevation Model (DEM), traces of opencast and underground mining of iron ore mining were located and classified. They occur in the zone of ore-bearing deposits outcropping on the north-eastern and north-western bounds of the Holy Cross Mountains. The DEM of an area covered by thirty-six (36) standard sheets of the Detailed Geological Map of Poland on a scale of 1:50,000 was thoroughly explored with remote sensing standards. Four types of ore recovery shafts with accompanying waste heaps were classified. The acquired data on the extent of former mining areas, covered with varying shafts and barren rock heaps could make a basis for distinguishing, according to historical data and in cooperation with archaeologists, the historical development stages of today’s steel industry. According to general knowledge, the iron industry in Europe instigate dates from the Roman times, in the Ist century BC to the IVth century AD, throughout the earlier and the late medieval times, up to the most recent the 1970ties. The usefulness of the LIDAR method has already been amazingly confirmed in archaeological researches worldwide. Many discoveries of ling forgotten, even large entities resulting from human activities in Asia and Central America especially were discovered owed to the LIDAR DEM. Also, traces of human settlements from various historical periods were discovered that way in Poland. The applicability of DEM based on LIDAR data is, in geological studies of surficial geodynamic processes and in geological mapping in Poland, rather contested.
A variety of optoelectronic devices (rangefinders, velocity meters, terrestrial scanners, lidars, free space optics communication systems and others) based on semiconductor laser technology feature low−quality and highly asymmetric beams. It results from optical characteristics of the applied high−peak−power pulsed laser sources, which in most cases are composed of several laser chips, each containing one or a few active lasers. Such sources cannot be considered as coherent, so the resultant beam is formed by the superposition of many optically uncorrelated sub-sources. Far−field distribution of laser spots in such devices corresponds to the shape of laser emitting area, which instead of desired symmetry shows layout composed of one or several discrete lines or rectangles. In some applications, especially if small targets are concerned, it may be crucial to provide more symmetrical and uniform laser beam cross−section. In the paper, the novel strategy of such correction, combining coherent and incoherent approaches, is presented. All aspects of technological implementations are discussed covering general theoretical treatment of the problem, diffractive optical element (DOE) design in the form of computer generated hologram (CGH), its fabrication and testing in case of selected laser module beam correction.