Combining 3D Imagery and Lidar with ArcGIS in Aerial and Mobile Applications
Combining 3D Imagery and Lidarwith ArcGIS in aerial and mobile applications Aldo Facchin – Geosoft Srl (Italy) www.geosoft.it
Geosoft Srl - ItalyWho we are ? An italian company focused on software products for … • Map production • 3D photogrammetry • LiDAR • Mobile Imaging & Laser Scanning (from vehicle) Founded in 1992 Main markets (last 3 years) : • 70-85 % Map, Survey and Engineering industry • 15-30 % Public Administration, University and Research
Geosoft Srl - ItalyOur offer… A family of ArcGIS Desktop stereoscopic extensions for : Aerial photogrammetry and lidar (with a patented method) Terrestrial Laser Scanning Mobile Laser Scanning
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combinedGeodatabase updating using orthophotos : Well known datatype Large diffusion Poor photointerpretation Difficult to collect XY position Impossible to collect HEIGHT / Z values Your world is flat We need a 3D system
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combinedGIS is a “decision support system”Which kind of decisions you can take if your data aren’t enough accurate ?Please take care about accuracy...
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combinedIf the ortophoto exists, also the overlapped images exist...“Imagery” is the cheapest dataset already ready for 3D 3D Imageryis part of the “photogrammetry” workflows and products LiDAR is the emerging technology naturally “born for 3D “
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combinedPhotogrammetry (3D imagery) alone is not enough… Optimal photointerpretation (image data is continuous) Use of RGB, CIR images with 8+ bit per channel Already experienced operators, well known procedures and system New digital cameras have bad B/H ratio so Z quality is poor Data quality is not constant (Z in particular) because depends on the operator (stereoscopic perception) Image correlation often have problems exactly where we need (for ex. roof edges)
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combinedLiDAR alone is not enough… Optimal precision (especially Z) respect to the photogrammetry at the same flight height Possibility to classify the points cloud Data quality is constant (Z in particular) because does not depend on the operator (snap) Data have low costs and short acquisition times Interpretation is very poor because the data are discrete Point density impacts a lot on cost The points don’t have directly the color of the objects XY precision is poorer than Z
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combinedThe solution :
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combinedThe solution : The operator move the cursor observing the imagery stereo scene The software update the cursor height according with the point cloud, using different alghoritms Stereo imagery are used for XY and photointerpretation LiDAR point clouds are used for updating collimation mark height (Z) The point cloud is better than using DSM or other resampled products The operator has only the “check” the collimation mark height (Z), not directly and carefully position it !
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combined We requested to register a patent for the industrial process of producing maps using 3D imagery and lidar... The European Patent Office approved it !!! The patent will be extended in Europe, USA, Canada, Brasil, India, etc.
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combinedCharacteristics of ArcGDS LiDAR method (patent pending)It’s a tool for the production of high quality 3D geodatabases. Photointerpretation is available (photos, 3D...not orthophoto) LiDAR acquisition allow much better Z precisions than photo- mapping or orthophoto digitalization Mapping (for ex. streets or buildings) is coherent with LiDAR Operator checks Z during mapping and eventually changes it manually Is for everybody because not require a high photogrammetric experience Snap uses cloud classification Transversal profile view helps operator for a better interpretation
Aerial Stereo Imagery and Lidar3D Imagery and Lidar are better if combinedKey concepts : Stereoscopy is available for all the users at low cost, inside ArcMap, for images and point clouds The time of proprietary CAD platform for maps data capture is over ! Combine stereo images and LiDAR point clouds to obtain the best accuracy and efficiency It’s the ideal tool for QC/QA after automatic feature extraction phase Can be bundled with raw data (images & point cloud) by data providers With this (patented) method… • medium format cameras can be used • low density point clouds can be used
Mobile Laser Scanning and Imagery ArcGDS for MLS
Mobile Laser ScanningUse video to quickly navigate and 3D stereoscopic vision accurate datacollectionNow… The current trend on MLS is to do all the work using laser scanner(s) point cloud The camera(s) are only for give color to point cloud Do you think to handle a mobile laser scanning road network project with a CAD ?
Mobile Laser ScanningUse video to quickly navigate and 3D stereoscopic vision accurate datacollectionWith the “Point cloud only” approach you need high density point cloud… More scanners Lower speed in mission Huge files to manageImpact on : system cost mission productivity post processing productivity
Mobile Laser ScanningUse video to quickly navigate and 3D stereoscopic vision accurate datacollectionOur idea… Try to use camera image sequences (video) to quickly navigate… Use the point cloud only for the 3D precise measure task Use the images to recognize the objects you have to collect Use 3D glasses to save time
Mobile Laser ScanningUse 3D glasses to save time, use images and point clouds as they areThe interface :
Mobile Laser ScanningUse 3D glasses to save time, use images and point clouds as they areThe solution : You can open the video window and the 3D laser window from any point in the ArcMap dataframe You can use normal ArcMap tools pointing in the video window or on the 3D laser window The 3D laser window can be viewed stereoscopically using 3D glasses With 3D glasses you see immediately if are picking More productivity, less mistakes productivity, the right point
Conclusion Images don’t replace point clouds and vice-versa Use the best of each data type Combine them GIS is necessary for a good data collection • for data consistency • for multiuser handling • for versioning • for integration with other sources (ex. ArcGIS Online) • etc. There are no more advantages on using CAD for 3D
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