AS INOVAÇÕES DO LASER AEROTRANSPORTADO: SUAS VANTAGENS PARA MAPEAMENTO DE DUTOS
inovacoes_laser_2007.pdf – 845 KB POR SILAS SALLEM FILHO
Esta pesquisa tem por objeto apresentar os resultados dos sistemas de perfilamento a LASER aerotransportado em experiências práticas para mapeamento de dutos. Para embasar as reflexões pretendidas, o trabalho desenvolve-se em dois momentos que se relacionam – o conceitual e o empírico. Num primeiro momento é feita uma revisão do referencial conceitual que compreende a criação dos primeiros equipamentos LASER comerciais até às vantagens advindas das inovações tecnológicas, para mapeamento de dutos. Num segundo momento, apresenta-se um panorama de experiências técnicas no mapeamento de dutos, que constatam inovações advindas das novas tecnologias dos sistemas a LASER, tais como: as melhorias no delineamento do terreno, através da grande quantidade de pontos emitidos pelo sistema; o aumento significativo da largura das faixas de vôo LASER em função dos equipamentos permitirem maior altura de vôo; o ganho de qualidade horizontal, na medição das coordenadas planimétricas e o ganho de qualidade das imagens obtidas a partir dos pontos do levantamento LASER. Por fim, constata-se a agilidade apresentada pelo mercado de LASER aerotransportado.
impact_of_lidar_nominal_post-spacing_on_dem_accuracy_and_flood_zone_delineation.pdf – 6.655 KB GEORGE T. RABER
JOHN R. JENSEN
MICHAEL E. HODGSON
JASON A. TULLIS
BRUCE A. DAVIS
JUDITH BERGLUND
Lidar data have become a major source of digital terrain information for use in many applications including hydraulic modeling and flood plane mapping. Based on established relationships between sampling intensity and error, nominal post-spacing likely contributes significantly to the error budget.
 BUILDING BOUNDARY TRACING AND REGULARIZATION FROM AIRBORNE LIDAR POINT CLOUDS
building_boundary_tracing_and_regularization_from_airborne_lidar_point_clouds.pdf – 4.490 KB APARAJITHAN SAMPATH
JIE SHAN
Building boundary is necessary for the real estate industry, flood management, and homeland security applications. The extraction of building boundary is also a crucial and difficult step towards generating city models. This study presents an approach to the tracing and regularization of building boundary from raw lidar point clouds.
 AN EVALUATION OF LIDAR-DERIVED ELEVATION AND TERRAIN SLOPE IN LEAF-OFF CONDITIONS
An_Evaluation_of_Lidar-derived_Elevations.pdf – 7.080 KB MICHAEL E. HODGSON
JOHN JENSEN
GEORGE RABER
JASON TULLIS
BRUCE A. DAVIS
GARY THOMPSON
KAREN SCHUCKMAN
The effects of land cover and surface slope on lidar-derived elevation data were examined for a watershed in the piedmont of North Carolina. Lidar data were collected over the study area in a winter (leaf-off) overflight. Survey-grade elevation points (1,225) for six different land cover classes were used as reference points. Root mean squared error (RMSE) for land cover classes ranged from 14.5 cm to 36.1. Land cover with taller canopy vegetation exhibited the largest error

 

 ASPRS RELEASES UPDATE TO LAS LIDAR DATA EXCHANGE FORMAT STANDARD
asprs.pdf – 788 KB
ASPRS released version 1.1 of the ASPRS Lidar Data Exchange Format Standard (LAS) at its 71ST Annual ASPRS Conference and Exhibition held in Baltimore, Maryland in March. This binary data exchange format is an industry standard for the exchange of lidar data between various hardware manufacturers, software developers, data providers and end users.

 

 DEM GENERATION AND BUILDING DETECTION FROM LIDAR DATA
DEM_Generation_and_Building_Detection_from_Lidar_Data.pdf – 7.185 KB RUIJIN MA
Object reconstruction has attracted great attention from both computer vision and photogrammetry communities, and new technologies are being introduced into this research society. Lidar (Light Detection And Ranging) has become well recognized in the geomatics community since the late 1990s. Compared with traditional photogrammetry, lidar has advantages in measuring surface in terms of accuracy and density, automatic, and fast delivery time.

 

 EFFECTS OF TERRAIN MORPHOLOGY, SAMPLING DENSITY, AND INTERPOLATION METHODS ON GRID DEM ACCURACY
Effects_of_Terrais_Morphology.pdf – 14.270 KB FERNANDO J. AGUILAR
FRANCISCO AGÜERA
MANUEL A. AGUILAR
FERNANDO CARVAJAL
This paper explores the effects of terrain morphology, sampling density, and interpolation methods for scattered sample data on the accuracy of interpolated heights in grid Digital Elevation Models (DEM). Sampled data were collected with a 2 by 2 meters sampling interval from seven different morphologies, applying digital photogrammetric methods to large scale aerial stereo imagery (1:5000).

 

 FILLING IN THE GAPS WITH COMPLEMENTARY TECHNOLOGIES
Filling_in_the_Gaps_with_Complementary_Technologies.pdf – 4.645 KB RON ROTH
The use of airborne laser profiling has increased in a varlety of surveying and mapping applications. Concurrently with this increase in usage, the performance of airborne laser profiling systems has increased dramatically over the past several years. Nonetheless, users of these systems have recognized that there are still applications in which airborne surveys provide inadequate results (compared to ground-based systems) despite current high performance levels. In this article we will review the history and convergence of airborne – and ground-based lidar technologies. We will also demonstrate how the two technologies can be employed either 1) separately ot 2) jointly in a complementary fashion.

 

 THE LAS I.I STANDART
The_LAS_I-I_Standard.pdf – 3.708 KB LEWIS GRAHAM,
ASPRS LIDAR COMMITTEE
The introduction of a standart file format (LAS 1.0) for lidar data in 2002 has been very successful as evidenced by the fact that all major software vendors have adopted the standart and customers are routinely requiring that lidar data be delivered according to this standard. As with any standard, usage has made it apparent that changes need to be made both due to omissions in the original design as well as continuing maturity of the lidar industry.

 

 RECENT U.S. GEOLOGICAL SURVEY APLLICATIONS OF LIDAR
Recent_US_Geological_Survey_Applications_of_Lidar.pdf – 1.240 KB VIVIAN R. QUEIJA,
JASON M. STOKER,
AND JOHN J. KOSOVICH
As lidar (light detection and ranging) techonology matures, more applications are being explored by U.S. Geological Survey (USGS) scientists throughout the Nation, both in collaboration with other Federal agencies and alone in support of USGS natural-hazards research (Crane et al., 2004). As the techonology continues to improve and evolve, USGS scientists are finding new and unique methods to use and represent high-resolution lidar data, and new ways to make these data and derived information publicly available. Different lidar sensors and configurations have offered opportunities to use high-resolution elevation data for a variety of projects across all disciplines of the USGS. The following examples are just a few of the diverse projects in the USGS where lidar data is being used.

 

 CONFIGURING AN AIRBORNE LASER SCANNER FOR DETECTING AIRPORT OBSTRUCTIONS
Configuring_an_Airborne_Laser_Scanner_for_Detecting_Airport_Obstructions.pdf – 2.614 KB CHRISTOPHER E. PARRISH,
GRADY H. TUELL,
WILLIAM E. CARTER,
AND RAMESH L. SHRESTHA
To ensure the safety of the national airspace system, the Federal Aviation Administration (FAA) oversees surveying programs with the good of geolocating vertical features that penetrate 3D Obstruction Identification Surfaces (OIS) around airfileds. These OIS are defined mathematically and are based on the layout of the runways, the types of eletronic navigation equipment used for each runway, and other factors. Under a series of interagency agreements, the National Geodetic Survey (NGS) is tasked with supplying obstruction survey data to the FAA.

 

 PERSPECTIVAS DE UTILIZAÇÃO DE SISTEMAS MICROELETROMECÂNICOS (MEMS) VISANDO A INTEGRAÇÃO GPS/INS DE BAIXO CUSTO
IntegrGPS-INS.pdf – 196 KB SANDRO REGINATO SOARES DE LIMA
SÍLVIO ROGÉRIO CORREIA DE FREITAS
CLÁUDIA PEREIRA KRUEGER
Em levantamentos geodésicos, a integração GPS/INS enfrenta desafios em relação a questões de alto custo dos instrumentos e ausência de recursos computacionais específicos. A utilização de dispositivos de baixo custo, baseados em tecnologia MEMS (MicroElectroMechanical Systems), procura a redução do custo instrumental. Desta forma, utilizou-se um dispositivo de baixo custo contendo acelerômetros baseados em MEMS. Entretanto, os sensores inerciais foram observados apenas em modo estático, em laboratório. Neste caso, as observações representam ruído que pode ser utilizado como parâmetro no processo de integração GPS/INS. O monitoramento de vibrações e da inclinação de estruturas são exemplos de aplicações que podem utilizar sensores operando desta forma. Conclui-se que os dispositivos MEMS são uma realidade viável para a pesquisa de baixo custo. Além disso, é esperado o desenvolvimento de novos sensores inerciais baseados em NEMS (NanoElectroMechanical Systems) considerando-se os atuais investimentos em Nanotecnologia.

 

 REPORT: ISPRS COMPARISON OF FILTERS
LiDARFilterComparisons.pdf – 1,29 MB GEORGE SITHOLE,
GEORGE VOSSELMAN
As one of the tools for rapid topographic feature extraction, the commercial use of airborne laser scanning (ALS) has gained wider acceptance in the last few years as more reliable and accurate systems are developed. While airborne laser scanning systems have come a long way, the choice of appropriate data processing techniques for particular applications is still being researched. The tasks in data processing include the “modeling of systematic errors”, “filtering”, “feature detection” and “thinning”. Of these tasks manual classification (filtering) and quality control pose the greatest challenges, consuming an estimated 60 to 80% of processing time and thus underlining the necessity for research in this are

 

 ESTADO ATUAL DOS SISTEMAS ALS NO BRASIL E NO MUNDO
estado.pdf – 42 KB PROFa. Ms. MARIA CECÍLIA BONATO BRANDALIZE
A técnica ALS (Airborne Laser Scanning), ou VLA (Varredura Laser Aerotransportada), permite a coleta de nuvens de pontos semi-aleatoriamente distribuídos sobre a superfície do terreno e, a partir do processamento off-line destas nuvens, a obtenção das coordenadas 3D georreferenciadas dos pontos coletados e a conseqüente geração de modelos digitais 3D (DEMs, DTMs e DSMs) da superfície varrida.

 

 PADRÕES DE CLASSIFICAÇÃO DE EQUIPAMENTOS LASER UTILIZADOS EM LEVANTAMENTOS TERRESTRES E AÉREOS
PadroesSegurancaLaser.pdf – 158 KB PROFa. Ms. MARIA CECÍLIA BONATO BRANDALIZE
PROF. Dr.-ING. JÜRGEN PHILIPS
O presente trabalho é resultado de uma pesquisa bibliográfica elaborada como parte do desenvolvimento da tese de doutorado da autora sobre equipamento laser aerotransportado. A pesquisa estendeu-se também aos equipamentos laser terrestres dada a importância de conhecer os padrões utilizados para sua classificação, em função do tipo de laser utilizado e dos riscos potenciais que representam à saúde humana.

 

 PERFILAMENTO A LASER: COMPARAÇÃO COM MÉTODOS FOTOGRAMÉTRICOS
brandalizeperf.pdf – 1.065 KB AMAURI ALFREDO BRANDALIZE
Uma das atividades que mais consomem tempo na Fotogrametria é a obtenção de Modelos Digitais de Elevação ou do Terreno (MDE ou MDT). Este subproduto cartográfico normalmente é utilizado para a retificação diferencial de ortofotos ou para obtenção automática de curvas de nível. O Perfilamento a LASER é uma tecnologia que está revolucionando esta metodologia, permitindo a obtenção do MDE de maneira mais direta, evitando processos fotogramétricos ou levantamentos com outras técnicas como o GPS. Este trabalho apresenta uma comparação de resultados na obtenção de MDT derivados de Correlação de Imagem, Curvas de Nível e Perfilamento a LASER. Também são enfocados os aspectos de remoção automática de camada vegetal no MDT, uma das características principais deste sistema.

 

 TERRAIN MAPPING
terrainmapping.pdf – 2.924 KB MARTIN FLOOD
BILL GUTELIUS
MATT ORR

 

 INSTANT EVALUATION OF BEACH STORM DAMAGE
instant_evaluation.pdf – 2.535 KB RAMESH L. SHRESTHA
BILL CARTER

 

 FLYING HIGHER WORKING FASTER
flying_higher.pdf – 2.573 KB MICHAEL CUDDY

 

 LASER-ALTIMETRY DEM’S APPLIED TO LAND SEISMIC EXPLORATIONS SURVEYS
laser_altimetry.pdf – 2.693 KB MICHAEL FLUCH
WOLFGANG REIL

 

 AIRBORNE LASER SCANNING FOR ELEVATION MODEL
elevation_models.pdf – 2.327 KB FRIEDRICH ACKERMANN

 

 AIRBORNE LASER SCANNING FOR ELEVATION MODEL
elevation_models_1.pdf – 3.522 KB CHUNG SAN HAN

 

 DTM DERIVATION WITH LASER SCANNER DATA – Promising Results in Germany
dtm_scanner.pdf – 3.370 KB HELMUT HOSS

 

 LIDAR PROCESSING: IT’S NOT BLACK MAGIC
LIDARProcessing.pdf – 59 KB ROBERT A. FOWLER
This is an oblique view of a point cloud of LIDAR points. The red portion of the image shows ground points, and the green portion of the image shows the vegetation (tree canopy) points. Software can usually define the difference through nearest-neighbor comparisons.

 

 PRODUCT DEFINITIONS AND GUIDELINES FOR USE IN SPECIFYING DELIVERABLES
ProductDefinitionAndGuidelines.pdf – 214 KB MARTIN FLOOD
Since the mid-1990s the science of laser altimetry has been actively adopted by the remote sensing community as a tool for the rapid generation of accurate, high-resolution, digital terrain models. The fundamental science behind laser altimetry has been studied for decades, going back to the 1960s, but it is only with the increased availability of off-the-shelf sensors and the emergence of commercial data providers that this tool has seen wider deployment and acceptance by geospatial data users. The advantages of laser altimetry include rapid turn-around times, generation of relatively high-accuracy, high-density data sets and the ability to map in areas of low contrast, low relief or relatively dense vegetation cover. The disadvantages include relatively high cost on a project basis, a lack of direct object-oriented information (imagery, spectral information), data processing issues related to robust, efficient feature extraction (bare earth, break lines) and a lack of common standards and professional practices. As a result laser altimetry, or lidar mapping as it is more commonly referred to in the mapping community, is increasingly used in conjunction with other sensors ranging from traditional film imagery to integrated digital cameras, synthetic aperture radar or hyperspectral scanners.

 

 SENSOR INTEGRATION AIDS MAPPING AT GROUND ZERO
sensor.pdf – 465 KB MARY E. HIATT, USA
Hours after the September 11.2001. attack on the Word Trade Center, the New York Office for Technology (NYSOFT) was tasked with gathering and managing the airborne data collection over Ground Zero. On September 14, they enlisted the help of Earthdata, an airborne mapping and remote sensing company headquartered in Washington, D.C.

 

 METHODS FOR MEASURING HEIGHT AND PLANIMETRY DISCREPANCIES IN AIRBORNE LASERSCANNER DATA
methods.pdf – 2.495 KB HANS-GERD MAAS
Airborne laserscanning (or lidar) has become a very important technique for the acquisition of digital terrain model data. Beyond this, the technique is increasingly being used for the acquisition of point clouds for 3D modeling of a wide range of objects, such as buildings, vegetation, or electrical power lines. As an active technique is often specified to be on the order of one to two decimeters. By reason of its primary use in digital terrain madeling, examinations of the precision potential of airborne laserscanning have so for been concentrated on the height precision. With the use of the technique for general 3D reconstruction tasks and the increasing resolution of laserscanner systems, the planimetric precision of laserscanner point clouds becomes an important issue.

 

 AIRBORNE LASER MAPPING FOR HIGHWAY ENGINEERING APPLICATIONS
highway.pdf – 195 KB RON BERG, M.A.Sc., O.L.S.
JAMES FERGUSON, B.Sc., O.L.S.
Airborne laser mapping integrates three technologies into a single system to produce accurate digital terrain models (DTM) of the earth’s surface. The three technologies, Light Detection and Ranging (LIDAR) using laser, Global Positioning System (GPS) satellites, and Inertial Navigation Systems (INS), have all been available for several years. Developments in all three technologies have allowed the integrated system to be utilized in an airborne environment with increasing levels of accuracy.

 

 EXPERIENCES OF 10 YEARS LASER SCANNING
10yrslaser.pdf – 417 KB CHRISTIAN WEVER AND JOACHIM LINDENBERGER, STEINFURT

 

 QUALITY CONTROL OF LIDAR ELEVATION DATA IN NORTH CAROLINA
ip05_nc_lidar_qc.pdf – 82 KB NORTH CAROLINA COOPERATING TECHNICAL STATE MAPPING PROGRAM
The requirements for digital elevation data for flood insurance studies should be determined early in the process. Typically, for hydraulic modeling, elevation data equivalent to 4′ contours (RMSE = 37 cm) are appropriate for rolling to hilly terrain, and elevation data equivalent to 2′ contours (RMSE = 18.5 cm) are appropriate for flat terrain. North Carolina specified a RMSE of 20 cm for coastal counties and RMSE of 25 cm for inland counties.

 

 AIRBORNE LASER SCANNING AND DERIVATION OF DIGITAL TERRAIN MODELS
airbornels_dem.pdf – 570 KB CHRISTIAN BRIESE, NORBERT PFEIFER
Airborne laser scanning is widely used for the derivation of terrain information in wooded or open areas but also for the production of building models in cities. For this, the generation of a digital terrain model (DTM) is also required. In this paper laser scanning, and the filtering and classification of laser scanner data with a specific algorithm are described. The results for test data sets are presented.

 

 AIRBORNE LASER SCANNING OR AERIAL PHOTOGRAMMETRY FOR THE MINE SURVEYOR
alsorphotogrammetry.pdf – 166 KB H. JAMIE, J. DAVID

 

 DUNWICH IRRIGATION AREA – COMPARING AIRBORNE LASER SCANNING WITH PHOTOGRAMMETRY
alswithphotom.pdf – 1.412 KB ©AAM GEOSCAN PTY LTD
Report on Airborne Laser Scanning (ALS) trials conducted over the Dunwich Irrigation Area on North Stradbroke Island.A digital terrain model was required under dense vegetation. Our client, Redland Shire Council, considered two options. One approach was to use existing 1:10,000 aerial photography, exposed just after a fire had reduced the vegetation on the site. The second approach was to use Airborne Laser Scanning. The existence of aerial photography exposed with little vegetation over the site, plus ALS data captured through dense vegetation offered an interesting comparison of the two survey methods.

 

 A COMPARISON BETWEEN PHOTOGRAMMETRY AND LASER SCANNING
comparisonlaserphotog.pdf – 102 KB EMMANUEL P. BALTSAVIAS
A comparison between data acquisition and processing from passive optical sensors and airborne laser scanning is presented. A short overview and the major differences between the two technologies are outlined. Advantages and disadvantages with respect to various aspects are discussed, like sensors, platforms, flight planning, data acquisition conditions, imaging, object reflectance, automation, accuracy, flexibility and maturity, production time and costs. A more detailed comparison is presented with respect to DTM and DSM generation. Strengths of laser scanning with respect to certain applications are outlined. Although airborne laser scanning competes to a certain extent with photogrammetry and will replace it in certain cases, the two technologies are fairly complementary and their integration can lead to more accurate and complete products, and open up new areas of application. q1999 Elsevier Science B.V. All rights reserved.

 

 DERIVATION OF DIGITAL TERRAIN MODELS IN THE SCOP++ ENVIRONMENT
dem-scop-laser.pdf – 1.931 KB NORBERT PFEIFER, PHILIPP STADLER AND CHRISTIAN BRIESE
Airborne laser scanning is widely used for the derivation of terrain information in wooded or open areas but also for the production of building models in cities. For this, the generation of a digital terrain model (DTM) is also required. In this paper the filtering and classification of laser scanner data with iterative robust linear prediction in a hierarchical fashion using data pyramids is described. The coarse-to-fine approach is advantageous because it strengthens the robustness of the method and makes it faster. The results for test data sets of the OEEPE are presented.

 

 AIRBORNE LASER SCANNING – A TOOL FOR MONITORING AND ASSESSING THE FORESTS AND WOODLANDS OF AUSTRALIA LASER ALTIMETRY REPORT 1
dnr_laser_altimetry_report_1.pdf – 1.591 KB CHRISTIAN WITTE, PHIL NORMAN, ROBERT DENHAM,
DAVE TURTON, DAVE JONAS, PHIL TICKLE
A methodology for forest inventory in south-east Queensland utilising airborne laser scanning was assessed. Trials were conducted in open dry sclerophyll forest in St Marys State Forest near Maryborough and dense wet sclerophyll and complex notophyll vine forest near Springbrook in the Gold Coast hinterland. Use of a laser scanner for the production of digital terrain models (DTM’s) of the ground and derivation of canopy height and foliage density was evaluated.

 

 WORKING GROUP ON LASER DATA ACQUISITION
laser_pesqoeepe_presentation.pdf – 708 KB EUROPEAN ORGANISATION FOR EXPERIMENTAL PHOTOGRAMMETRIC RESEARCH – OEEPE

 

 ACQUISITION OF LASER DATA
laser_pesqquestionnaire.pdf – 69 KB EUROPEAN ORGANISATION FOR EXPERIMENTAL PHOTOGRAMMETRIC RESEARCH – OEEPE

 

 OEEPE PROJECT ON LASER DATA ACQUISITION
laser_pesqreport_1.pdf – 135 KB EUROPEAN ORGANISATION FOR EXPERIMENTAL PHOTOGRAMMETRIC RESEARCH – OEEPE

 

 ON THE MATCHING ACCURACY OF RASTERISED SCANNING LASER ALTIMETER DATA
laseraccuracy.pdf – 165 KB AVRIL BEHAN
For certain applications irregularly distributed scanning laser altimeter data need to be rasterised – such as for use in GIS systems and for creating DEMs. Also, least squares matching on a raster grid can enable the measurement of planimetric and height shifts between overlapping strips of laser data. The shifts are a manifestation of errors in the laser altimeter, most of which are caused by the positioning elements of the system (GPS and/or INS). These translations form the input into a block adjustment to correct for relative and absolute errors. Here a discussion of the issues related to deriving a regular grid of 2.5D points from the original data is presented, with particular reference to the interpolation method, grid size, and quantisation level. An interpolation method based on a TIN of the original points with a grid size that relates as closely as possible to the point density at acquisition is found to give the best results. 8-bit quantisation is found to be sufficient for height differences of up to 100m.

 

 THE LOW DOWN ON LIDAR
lidar.pdf – 18 KB ROBERT A. FOWLER
Every once in a while a technology suddenly seems to catch peoples’ imagination and you start hearing about it all the time. That’s been happening with LIDAR recently. What is LIDAR? Well, like radar, it’s an acronym, except in this case it stands for LIght Detection And Ranging. What does that mean? It is the technology, which uses light, specifically a laser light, to measure distance.

 

 RE&C PINPOINTS SUCCESS WITH LASER SYSTEM AT DETROIT EDISON
raythonarticle.pdf – 428 KB RAYTHEON ENGINEERS & CONSTRUCTORS