International cooperation and technology transfer

Fras, Mojca Kosmatin

Bibliographic data

Monograph

Persistent identifier:: 856490555

Author:: Fras, Mojca Kosmatin

Title:: International cooperation and technology transfer

Sub title:: Ljubljana, Slovenia, February 2 - 5, 2000 : proceedings of the workshop

Scope:: VI, 163 Seiten

Year of publication:: 2000

Place of publication:: London

Publisher of the original:: RICS Books

Identifier (digital):: 856490555

Illustration:: Illustrationen, Diagramme

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: A LOW COST MOBILE MAPPING SYSTEM. A. Vettore, A. Guarnieri

Document type:: Monograph

Structure type:: Chapter

A LOW COST MOBILE MAPPING SYSTEM A. Vettore, A. Guarnieri C.I.R.GEO (Interdepartment Research Center for Cartography, Photogrammetry, Remot Sensing and GIS) AGRIPOLIS - Statale Romea 16 35020 Legnaro (Padova) Phone +39-049-8272688 , fax +39-049-8372713 e-mail: vettoan@uxl.unipd.it Commission VI, Working Group 3 KEY WORDS: Mobile Mapping, Photogrammetry, GPS ABSTRACT In this work an alternative method, respect today’s tipical road survey, is presented. Tipically, a road survey is carried out by a team composed by three operators at least, that moves with a vehicle on which an odometer is mounted on the rear in order to measure the effective travelled road. Given this operational procedure, a road survey requires, as a rule, a lot of time, resulting therefore very laborious and expensive regarding the employement of economic and human resources. Possible solutions to these problems could be represented by integration of Computer Vision technology with modern satellite positioning system, as GPS. Also in agreement with this idea, GeoVision, a digital photogrammetric software for road survey, has been developed at the University of Padua (Italy). The system consists of a van equipped with two digital cameras, Sony XC75CE recording in continous way the surveyed environment and a GPS receiver that provides post-processed differential positions. From a pair of correspondent digital images, the 3D position of a feature can be determined in a global reference system (namely WGS-84), by integration of photogrammetric triangulation techniques and computer vision algoritms. In following sections the tools regarding digital image processing subsystem of GeoVision will be described in detail. 1. INTRODUCTION The use of a geographic information system (GIS) as decision tool for land and infrastructures management is even more increasing by public administrations so as private companies. This has resulted in a demand of a more precise GIS in planning and in an increasing demand for efficient data acquisition systems and up date of existing databases. Therefore all these require ments make GIS information updating a permanent task. Traditionally, GIS data acquisition is a laborious process, requiring digitization of existing maps, manual data entry during the survey and other time consuming techniques and therefore have limited the applicability and uselfuness of GIS to potential users. From this point of view the automation and speed up of GIS data acquisition represent a very important issue in cases where field surveys have to be performed ([3] and [8]). In order to address the problems of update and reliabi lity of GIS information, a low cost Mobile Mapping System, GeoVision, has been developed at the Univer sity of Padua (Italy). The system is based on a van equipped with two digital b/w cameras Sony XC75CE, with a basic format of 768x582 pixels, a GPS receiver an odometer and an analogue color videocamera. The CCD cameras, mounted on the front of the vehicle, record in continous way the surveyed environment: on one hand they can provide more detailed information of objects on the earth in comparison to aerial photo graphs and remote sensing satellite images, on the other hand CCD images have to be georeferenced in order to supply 3D information about object position. To this aim the image acquisition stream is synchro nized with GPS data collection via the PPS (Pulse Per Second) signal of the GPS receiver clock: in this way for each image pair it is possible to recover the geogra phic position of the cameras at the time of the shot. When signal blockages or poor GPS satellite geometry occur, the PPS signal is no more available until the minimum number of useful satellites is reacquired: in these cases the image acquisition is driven by the odo meter, which data can be also used to interpolate the GPS positions. During the survey analogue images are also recorded by a color camera: these images are used in post-processing to extract all useful attributes, i.e. qualitative features, of selected objects of interest. All on board devices are controlled in real time via the Gpslmage software, running on a PC Pentium III pro vided with a 13 GB Hard Disk. This high capacity allows up to 4 hours data recording, capturing two digital images, each of 450 KB, every second. 155

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