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Digital Airborne Camera Certification (EuroDAC²)
Digital Camera Calibration & Validation

News - Certification - Calibration -  Progress & Documents - Members - Contact

 

EuroDAC2 core team meeting at ICC Barcelona

Beginning of April 2009 the EuroDAC2 core competence team met again to proceed with certification and validation activities. This time the meeting took place at ICC Barcelona, Spain. The core group was supported by ICC experts J. Talaya, W. Kornus, R. Arbiol, L. Martinez & A. Ruiz. Their competences allow for deep discussions on geometrical and radiometrical topics. The meeting notes also include the links to the given meeting presentations.

 

EuroDAC2 core team meeting at IGN Paris

The second meeting of EuroDAC² core competence group was organized at IGN Paris at September 24-25, 2008. The meeting’s primary focus was to review the current activities and to define the future steps. Additional guided tours in IGN laboratories MATIS and LOEMI and the discussions with IGN experts clearly illustrate the most recent developments in digital imaging and processing and helps to stimulate own discussions in future certification activities.  The most recent findings are documented in the meeting notes.  During the meeting the team member Dr. Didier Boldo (IGN) was replaced by his colleague Dr. Marc Pierrot Desseilligny (IGN), who now represents IGN expertise within the team.

 

EuroDAC2 core competence team meeting Castelldefels

The first meeting of the EuroDAC2 core competence team took place at January 30, 2008, parallel to the EuroCOW workshop held in Castelldefels, Spain. The full group met, where D. Boldo and R. Reulke were replaced by one of their colleagues, respectively. Additionally one representative from the US also involved in the USGS Quality Assurance Plan was attending, physically representing a link between both European and US certification strategies.

Coreteam Castelldefels
The group members (from left to right): N. Paparonditis (IGN France, in place of D. Boldo), S. Bauer (DLR Berlin, Germany, in place of R. Reulke), G. Grenzdörffer (Universität Rostock, Germany), L.-E. Blankenberg (Blom Geomatics, Norway), M. Cramer (Universität Stuttgart, Germany), R. Alamus (ICC Barcelona, Spain), D. Moe (guest, involved in the US Geological Survey Quality Assurance Plan) and E. Honkavaara (FGI Finland, Masaala). S. Bovet (Swisstopo, Switzerland) also attended but is missing on the photo.

The following future steps have been decided during the meeting:

  1. Work on transparent and completely described calibration processes and the unique, comparable and unambiguous presentation of calibration results in calibration protocols. So far the results from manufacturer calibrations are listed in sometimes very extensive calibration protocols, and this information is presented in quite heterogeneous ways. A more unified way of result presentation and uniquely definition of parameters will directly influence the user friendliness and acceptance of systems.
     
  2. Work on the optimal design of airborne calibration and validation test fields and the corresponding test methods to comprehensively validate the system performance. The future role of test fields for in-situ calibrations and comprehensive performance tests of individual sensor is obvious from the above discussions. Still the processes and the final layout have to be defined. Note, that performance tests have to cover the geometry and radiometry as well. First substantial evaluations on the layout of such test procedures are already done by Finnish Geodetic Institute FGI. EuroDAC2 developments will be based on this investigation.
     
  3. Work on the formation of a network of international calibration and validation test field providers. All test fields have to be independent, of comparable layout and will offer identical user policies. EuroDAC2 has identified four primary test fields already used for the last years for European airborne tests. These test fields are maintained by
     
    • the Finnish Geodetic Institute (Masaala, Finland), namely the Sjökulla test site
    • the University of Pavia (Pavia, Italy), namely the Pavia test site
    • the Universitaet Stuttgart (Stuttgart, Germany), namely the Vaihingen/Enz test site, and
    • the University of Life Sciences (Aas, Norway), namely the Fredrikstad test site.
       
  4. EuroDAC2 will work on the regular distribution of similar test sites throughout Europe, which then can be used under comparable conditions.

 

For more details please have a look at

 

European Digital Airborne Camera Certification EuroDAC² - The core competence group is there!

The expert team working on the concept for a future European approach for digital airborne camera certification is now complete! Six experts from science, national mapping, standards and commercial companies will be responsible for the next project steps. The group members are presented in the following (in alphabetical order):

Image of Ramon Alamus

 Mr. Ramon Alamús is working in the Photogrammetry Section of the Geodetic Department at the Institut Cartogràfic de Catalunya (ICC), Spain. There he is participating in all activities in the field of digital airborne cameras, from acquisition and processing of the Intergraph/ZI-Imaging DMC data to image orientation and sensor modelling.
Image of Leif-Erik Blankenberg Dr. Leif-Erik Blankenberg is technical director at Blom Geomatics AS, Norway. He now is responsible for flights and products obtained from the Microsoft Photogrammetry / Vexcel Ultracam digital camera. Besides his has a strong scientific background in GPS trajectory computations for photogrammetric applications.
Image of Didier Boldo Dr. Didier Boldo from Institut Geographique National (IGN), France is the director of the laboratory MATIS at IGN. His main competencies are in digital image processing, 3D reconstruction and mathematical adjustments and optimisation. He is specialist of calibration and aerial triangulation topics at IGN from both research and production point of views.
Image of Stephane Bovet Mr. Stéphane Bovet is head the photogrammetry and remote sensing section at the Swiss national mapping agency swisstopo. During the last decade, he has been involved in the implementation and use of digital sensors to generate imagery as well as DTMs. He is specialized in classical frame images as well as pushbroom or satellite images.
Image of Michael Cramer Dr. Michael Cramer is senior lecturer at the Institute for Photogrammetry (ifp) at Universitaet Stuttgart, Germany. Since several years he is working in the field of airborne sensor orientation and calibration/validation of digital aerial cameras. Currently he is chairing the EuroSDR science commission I - Sensors, Primary data acquisition and Georeferencing.
Image of Ralf Reulke Prof. Dr. Ralf Reulke is professor for Computer Vision at the Computer Science Department, Humboldt Universität zu Berlin, Germany. Besides, he is associated with the German Aerospace Centre (DLR) where he is heading the signal and image processing group in the Institute of Transportation Research. As physicist he has strong scientific background in optical and sensor characteristics. Currently he is also chairing the standards group Photogrammetry and Remote Sensing of the German Standards Organization (DIN).

Their detailed address information can be accessed here (PDF-File). This core competence group will be closely linked to the activities of other EuroSDR projects which are dealing with the similar or neighboured scientific topics. Continuous information exchange will also strengthen the EuroDAC² initiative. In this context the following three projects are of concern:

  • Medium Format Digital Cameras
    Project leader: Dr. Görres Grenzdörffer (Universität Rostock, Germany)
  • Radiometric Performance of Digital Cameras
    Joint project leaders: Eija Honkavaara, Lauri Markelin (Finnish Geodetic Institute (FGI), Finland) & Roman Arbiol (Institut Cartogràfic de Catalunya (ICC), Spain)
  • Radiometric Calibration of Airborne Laser Scanning (ALS) Intensity
    Joint project leaders: Prof. Dr. Juha Hyyppä et al (Finnish Geodetic Institute (FGI), Finland), Dr. Hannu Hyyppä (Helsinki University of Technology, Finland) & Prof. Dr. Wolfgang Wagner et al (Vienna University of Technology, Austria)

 

New EuroSDR project “Medium Format Digital Camera” started

At the 111th EuroSDR science and steering committee meetings delegates officially approved the project proposal for a new activity related to the analysis of the potential of medium format digital airborne cameras. This project will also be based on the already established experts’ network “Digital Camera Calibration” originated from the earlier project in large-format camera calibration and validation. Project leader will be Dr. Goerres Grenzdoerffer from Universitaet Rostock.

The following gives a short overview on the project design, the complete project proposal is available here (PDF File). Additionally accompanying presentation slides can be accessed via (PDF File).

  • Collection of publicly available material on medium format digital camera systems to compile an extensive report describing the currently used practice and methods (Phase 1).
  • Empirical testing of 4 – 6 professional camera systems with focus on the adoption of commonly accepted procedure(s) for camera calibration and testing, based on the experiences from the frame cameras (EuroDAC²). Radiometric tests in addition to the investigations in the EuroSDR project Radiometric Aspects of Digital Photogrammetric Images (Phase 2).

As a result of Phase 1 it is expected to present a report which will be compiled with the help of all project participants, i.e. camera producers and users. We would like to invite all to contribute with their experiences. Such a summary will help to create a common knowledge base for the formulation on future strategies and later e xperimental work in Phase 2. Such status report could be helpful for system users to gain their experience with medium format digital cameras. This aspect was not covered on the former Digital Camera Calibration network activity. Furthermore this report should list open problems which need to be solved.
The second phase should focus on the adoption and adjustment of commonly accepted procedure(s) for camera calibration and testing. This has to be aligned with the works done in the EuroDAC² project. It seems to be necessary to concentrate on some of the technical aspects in a sequential order, possibly starting with geometrical aspects and verification in a limited number of test flights by different camera producers and discussion on radiometric and image quality aspects. One aspect is the design for optimal calibration flight procedures to be tested then empirically. It has to be checked whether appropriate flight data can be made available for the project. Another aspect is a collection of recommendations of producers on how customers should calibrate and do the processing. Since medium format cameras are portable, radiometric tests may be performed in a lab, e.g. at German Research Centre DLR. Alternatively lab facilities of journals for professional photographers may used. The definition of goals and the design of empirical tests has to be discussed based on the report compiled in Phase 1.

 

First project sketch on EuroSDR project “Radiometric Aspects of Digital Photogrammetric Images” available

EuroSDR will recently start a new project covering the “Radiometric Aspects of Digital Photogrammetric Images”. Official project launch will be in May 2008. Goal of this new activity is to improve knowledge on radiometric aspects of digital photogrammetric cameras. Based on a review of existing methods and procedures for radiometric image improvements, a comparison of these techniques on the same test data set is planned to compare and share operative solutions. Analysis of the benefit of radiometric calibration will point out the new application fields of digital airborne cameras like classification, quantitative remote sensing, change detection etc. Some more details on the project plan are given here (PDF File).
The project will be headed by Eija Honkavaara and Lauri Markelin, Finnish Geodetic Institute (FGI) and Roman Arbiol, Institut Cartogràfic de Catalunya (ICC).
Their activities are also aligned with the EuroSDR project “Medium Format Digital Cameras” under leadership of Görres Grenzdörffer, University of Rostock and the EuroDAC² initiative on digital camera certification, headed by Michael Cramer.

 

European Digital Airborne Camera Certification officially launched

The European Digital Airborne Camera Certifaction (EuroDAC²) initiative was officially accepted by the EuroSDR Science Committee and Board of Delegates in Rotterdam, The Netherlands, May 24, 2007. A position paper is now available which describes this new initiative on the certification on a European level (). Besides it gives basic information on the already ongoing certification approaches, like the USGS quality assurance plan for the United States. In addition to its information content, the paper encourages the reader to support the initiative with his expertise and individual requirements for such future such certification or standard. The responsible project team invites all persons involved in the acquisition, processing and use of such digital airborne sensor data and products to actively participate in the European certification process. Support this activity with your individual experiences, recommendations and ideas! In this way the initiative should lead to a European certification, which avoids solutions specific to a single country and thus becomes accepted not only by users but also by system suppliers.
In addition to this position paper the main ideas of the EuroDAC² initiative have already been presented at the Intergraph/ZI Usermeeting in Aalen (May 2, 2007, in german) () and at the ASPRS annual conference in Tampa / Florida (May 8, 2007). ()
Besides, a paper on this new EuroSDR approach was submitted and accepted for publication in the GIM International journal (externer Link http://www.gim-international.com/) September issue, 2007. This paper will be accompanied by a second paper from the US Geological Survey illustrating the USGS quality assurance plan. Thus two of the main certification activities in digital airborne imaging will be presented in this GIM issue.

 

European initiative on digital airborne camera certification

Within the last months the topic of a future European digital airborne camera certification process has been discussed in the EuroSDR management and science team extensively. This topic was also addressed at the most recent Intergraph ZI European DMC User Meeting in Gävle/Sweden. Both, digital camera users and national mapping and cadastre agencies showed considerable interest in such independent certification. Obviously, the former calibration of analogue cameras, which in the same way certifies the systems' performance, cannot be transferred to the new digital airborne camera systems. It is one of the most important findings of the EuroSDR Camera Calibration Network activities, that for today's digital sensors not only the camera but the whole data processing is of major impact on the obtained quality of final results. Thus, new ways of system certification covering the whole data generation process have to be identified and implemented.

The US Geological Survey has already defined a concept for such new system certification process. Some more details on their certification can be seen from http://calval.cr.usgs.gov/digital_aerial_imaging_quality_assurance.php.

This so far is the only strong initiative in official digital airborne camera certification. The USGS process is only relevant for systems used in the Us, nevertheless it seems to be obvious that other countries soon will adopt those certification or alternatively will develop their own procedures. EuroSDR decided to be in charge of the initiation and coordination of an European based digital camera certification. A close cooperation with USGS was established to share experiences and to align both certification processes as much as possible. Nevertheless, the European approach also might (partially) differ from the USGS concept if lacks are identified or adoptions to the European situation are necessary.
The final design of the future Eurpean certification is dependent on the recommendations from mainly system users supported by academia and system manufacturers. The idea was to start discussions on this topic within the group of digital camera experts already established through the EuroSDR Calibration Network. Besides, all other persons involved with digital airborne imaging and willing to contribute to this European certification activity are invited to directly contact M. Cramer.

 

Digital Camera Calibration project now completed

With the availability of the Phase 2b results the Digital Camera Calibration and Validation activities are now completed. Altogether 13 different institutions have been actively participated in the phase 2 and phase 2b empirical data processing. 5 participants participated in the DMC phase 2b analysis, 4 participants returned their results from the UltracamD phase 2b processing. Altogether 80 different phase 2b solutions were analysed by the pilot centre. Major findings of the empirical analyses have already been presented at the recent ISPRS workshop “High resolution Earth Imaging” organized by IPI, University of Hannover, Germany. This presentation can be accessed here ().
So far no final report is compiled. This report will become available in fall 2007. Another paper focusing on this EuroSDR test is invited for the upcoming Photogrammetric Week 2007 in Stuttgart, Germany and can be accessed here.

 

Phase 2 analysis extend

So far the analysis of phase 2 empirical test flight data was based on the images from the different cameras directly. The results of active phase 2 participants were obtained from their individual measurements of control, check and tie point image coordinates. Especially for the DMC and UltracamD data, these image measurements were very demanding due to the less optimal image radiometry. As it was mentioned in the data description, both flights were flown late fall with very low sun angles (below 30deg). Needless to say, that the quality of image measurements and the applied set of self-calibration parameters during adjustment are the two main things influencing overall system accuracy. Since the main scope of this study is on the investigation of additional parameters, it was decided to extend phase 2 like follows: The pilot centre now has prepared “reference” image coordinates for all of the DMC and Ultracam flights. These image coordinates have been measured very carefully and have been checked for their correctness. These “reference” image coordinates now can be used for the AT of each individual participant. Since all participants are using the same image measurements the influence of different additional self-calibration parameter sets on the overall accuracy will become more obvious. Each network participant or any other interested person is encouraged to apply for this data set and to join this new phase 2b! The data will be transferred on demand via email attachments. Please have a look at this document () for some more details on the phase 2b data. If you are interested in phase 2, please contact M. Cramer. Please note again, you not necessarily have to be an active member of phase 2 already to start your activities in this new phase 2b!

 

Phase 2 - Preliminary results

Within phase 2 of EuroSDR project on Digital Camera Calibration the offered ADS40, DMC, and UltracamD data was requested by 18 different network members. DMC and UltracamD data sets were distributed to 7 members each, whereas the ADS40 data set was requested 4 times.
Till now (status October 10, 2006) results from 12 network participants were submitted to pilot centre for absolute accuracy analysis.
The results from the different data sets can be found here:

Please also look at this presentation (), which was held at the EuroSDR science and steering committee meeting in October 2006.

 

Start-up of experimental Phase 2

Empirical data sets now available! With certain delay due to several reasons the project core team is glad to announce the empirical airborne data sets to be distributed within the second experimental oriented phase 2 of the project. Thanks to all the persons, who provided access to that data. Explicit thank has to be expressed to representatives of externer Link TerraTec, externer Link IFMS and externer Link Leica for data provision and continuous support!
Despite this delay, the project core group very much hopes to encourage almost all registered and potential new interested people to actively participate in phase 2. We believe that the simultaneous analysis of the same empirical data from different network members will not only increase the individual knowledge and experience of each network member, even more, after re-collecting and documenting the individual results, more general recommendations on the most optimal way of processing of data of the different types of sensor will become possible. And this would be helpful for all of us and any future system users. Based on your effort and active support this project will gain in importance and international reputation!

A detailed overview on the upcoming schedule is given here. A brief description of the three different test flight data, namely ADS40 (flown in Vaihingen/Enz test site) and DMC and UltracamD (flown in Fredrikstad test site) can be obtained from here.

We decided to distribute only one data set for each participant in this first round of data distribution. The distribution itself will be done on USB/Firewire portable discs using a land mail chain, i.e. the data is shipped from one network member to the next member directly and finally will return to the pilot centre.

In case anyone, who was up to now not actively involved in the network activities, is interested in joining the empirical project phase, please contact the project coordinator M. Cramer directly.

 

Background

With the advent of first digital airborne photogrammetric imaging sensors in operational environments an immediate focus on certification on digital camera calibration appears. There is a definite need for sensor calibration in the airborne photogrammetric community, which is fully supported by national mapping agencies. This calibration is well established for the traditional analogue frame cameras but the process has to be modified when dealing with new digital sensors. Since the principle architecture of such digital systems is fairly different (i.e. line scanning approaches versus frame based solutions, multi-head large format systems versus single-head medium format systems, synchronous versus syntopic image data acquisition) individual procedures for system calibration are necessary. With an optional combination and in case of line scanning systems mandatory tight integration of additional GPS/inertial components this situation becomes even more complex. Within this context the need for development of a generally accepted calibration procedure is evident. Such procedures will not only support suppliers and producers of digital camera systems but also provide additional means for potential digital camera users to investigate their features.

On the 103rd EuroSDR Science and Steering Committee Meeting from October 15-17, 2003 in Munich/Germany the new EuroSDR project on Digital Camera Calibration has been accepted and established officially. The goal is to derive the technical background for digital camera procedures based on scientific theory and empirical research. Legal and certification aspects are put to the background for the time being. Within a first initial meeting in September 2003 all larger digital airborne camera producers already signalized their willingness to support this EuroSDR initiative. Till now about 25 experts from camera manufacturers, other companies and research already joined this project. Since this project is open for all other people everyone who is interested in digital airborne camera calibration is invited to become an active member to join his experiences in this project network. Please contact M. Cramer.

 

Objectives

The objective of this Digital Camera Calibration project is two-fold:

  • Collection of publicly available material on digital airborne camera calibration to compile an extensive report describing the currently used practice and methods (Phase 1).
  • Empirical testing with focus on the development of commonly accepted procedure(s) for airborne camera calibration and testing, based on the experiences and advice of individual experts (Phase 2).

As a result of Phase 1 it is expected to present a report which will be compiled with the help of all project participants, i.e. camera producers and users. Such a summary will help to create a common knowledge base for the formulation on future strategies and later experimental work in Phase 2. This status report could be helpful for digital camera system users to gain their experience with digital camera calibration aspects. Furthermore this report should list open problems which need to be solved. All participants of the first initiate meeting welcome the idea that this report is open to producers, users and customers.

The second phase should focus on the development of commonly accepted procedure(s) for camera calibration and testing. It seems to be necessary to concentrate on some of the technical aspects in a sequential order, possibly starting with geometrical aspects and verification in a limited number of test flights by different camera producers and discussion on radiometric and image quality aspects. One aspect is the design for optimal calibration flight procedures to be tested then empirically. Another aspect is a collection of recommendations of producers on how customers should calibrate and do the processing. It requires a fine definition of goals which should not lead to direct comparisons of cameras, but to individual recommendations for each major camera type. The definition of goals and the design of empirical tests has to be discussed based on the report compiled in Phase 1. The aspired timetable for the different project phases is given in the following figure.

It has to be mentioned that the project itself will focus on the calibration of digital airborne camera systems only. The combination of LIDAR and imaging sensors is not considered since this is a registration and no calibration problem.

 

Project progress and documents

Please use Acrobat Reader 5.0 or higher!

 

Network members (Status November 2007)

# Organization Members
Systemproviders
I.1 ADS 40, Leica Geosystems Udo Tempelmann,  Peter Fricker, Ulrich Beisl, Gert Ferrano
I.2 DMC, ZI-Imaging Christoph Dörstel, Dr. Mostafa Madani
I.3 UltracamD, Vexcel Dr. Michael Gruber
I.4 DIMAC, Dimac Systems Pierre Louis, Julien Losseau
I.5 DSS, Applanix Corp. Dr. Mohamed Mostafa, Eric Liberty
I.6 Starimager, Starlabo Corp. Dr. K. Tsuno
I.7 3-DAS-1, Wherli & Ass. Inc. Dr. Hans. J. Wehrli
I.8 DigiCAM, IGI mbH Dr. Jens Kremer, Michael Müller
Industry & other software developers
II.1 ISTAR Dr. Philippe Nonin
II.2 GEOSYS Technology Solutions Dr. Babak Ameri
II.3 Vito Mr. Jurgen Everaerts
II.4 Optical Metrology Centre Dr. Tim Clarke
II.5 ORIMA Dr. Ludger Hinsken
II.6 inpho Tobias Heuchel
II.7 DLR Oberpfaffenhofen Prof. Manfred Schroeder, Dr. Peter Reinartz, Dr. Rupert Müller, Dr. Manfred Lehner
II.8 DLR Berlin Frank Scholten, Klaus Gwinner
II.9 dgap Dirk Stallmann
II.10 CSIRO Xiaoliang Wu
II.11 stereocarto Thomas Fdez. De Sevilla Riaza
II.12 Geosense Ltd. Ansie Clarence
University
III.1 Ohio State University Prof. Dr. Toni Schenk, Prof. Dean Merchant
III.2 ETH Zürich Prof. Dr. Armin Grün, Dr. Manos Baltsavias, Sultan Kocaman, Henri Eisenbeiss, Jafar Amiri Parian
III.3 University of Glasgow Prof. Dr. Gordon Petrie
III.4 University of Rostock Dr. Görres Grenzdörffer
III.5 University of Stuttgart Dr. Norbert Haala, Dr. Michael Cramer
III.6 University of Hannover Dr. Karsten Jacobsen, Prof. Dr. Christian Heipke
III.7 Humboldt University Berlin Prof. Dr. Ralf Reulke
III.8 University of Applied Sciences Stuttgart Prof. Dr. Eberhard Gülch
III.9 University of Applied Sciences Anhalt Prof. Dr. Hartmut Ziemann
III.10 Institute de Geomatica Castelldefels Dr. Ismael Colomina
III.11 University of Norway Aas Dr. Ivar Maalen-Johansen
III.12 University of Nottingham Dr. Martin J. Smith
III.13 University of Pavia Prof. Vittorio Casella, Marica Franzini
III.14 University of Leon Benjamín Arias Pérez
III.15 Open Skies Prof. Dr. Hartwig Spitzer
III.16 ICSM - Australian Intergovernmental Committee on Survey and Mapping - Permanent Committee on Topographic Information - Special Interest Group on Imagery Paul Duncan
National mapping agencies & other authorities
IV.1 Swedish Land Survey Dr. Dan Klang, Daniel Akerman
IV.2 Finnish Geodetic Institute Prof. Dr. Risto Kuittinen, Prof. Dr. Juha Hyyppä
IV.3 British Ordnance Survey Paul Marshall
IV.4 Swisstopo - Landestopographie Dr. André Streilein, Stéphane Bovet
IV.5 US Geological Survey Dr. Greogory L. Stensaas, Dr. George Y. G. Lee, Dr. Jon Christopherson
IV.6 ICC Barcelona Dr. Julià Talaya, Ramon Alamus, Roman Arbiol
IV.7 IGN France Dr. Marc-Pierrot Deseilligny
IV.8 Bundesamt für Eich- und Vermessungswesen (Austria) Michael Franzen
IV.9 Instituto Cartográfico Valenciano Raquel Fernández
IV.10 ITACYL - Junta de Castila y León David A. Nafría
IV.11 Bayrisches Landesamt für Vermessung und Geoinformation Wolfgang Stößel
IV.12 Institut Géographique National Jean Théatre, Steven Roovers
IV.13 Landesvermessungsamt Baden-Württemberg – Abteilung Geodäsie Berthold Klauser, Manfred Gültlinger
IV.14 AdV – Arbeitskreis Geotopographie Sven Baltrusch, Jörg Schaffer
IV.15 Landesvermessungsamt Schleswig-Holstein Weber, Jürgen (Landesvermessungsamt S-H)
IV.16 Statens kartverk Norway Lars Mardal

 

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