For the latest news on the Orfeo Toolbox
As you may know, the International Geoscience and Remote Sensing Symposium (IGARSS) will take place in Cape Town this year, starting on July 13th.
We are very proud to have a special session about OTB. You can find the detailed program here: (first part, second part).
If you attend IGARSS, don’t forget to come and see some interesting talks about OTB uses and applications.
CNES is proud to announce the availability of the new major stable version of ORFEO Toolbox.
As usual, you can go to http://www.orfeo-toolbox.org/ and follow the download link or get directly to Sourceforge http://sourceforge.net/projects/orfeo-toolbox/ and get the packages there. Full source code, Software Guide and Windows binaries are available.
The Geoscience and Remote Sensing Society of IEEE, publishes a quarterly Newsletter about “the science and engineering of remote sensing of the Earth’s land, oceans, and atmosphere”.
The last edition (March 2009) features a 7-page article about OTB which is entitled: “Open Source Remote Sensing: Increasing the Usability of Cutting-Edge Algorithms”.
The article explains the goals and philosophy of OTB and presents some examples of available features.
The full pdf file for the Newsletter can be downloaded here.
At first, the visualization module of the Orfeo ToolBox was designed as a lightweight tool to view results at the end of a pipeline and to be integrated into graphical OTB applications. But as the number of these applications increases, we started adding more and more features to this tool: polygonal ROI selection, link betweeen displays, histograms … Since the initial design was not supposed to handle such things, code was growing and side-effects became more and more frequent. Needless to say, the cost of adding new functions tends to grow along with the code … It was about time to do something.
For a few weeks now, the OTB development team has been working on this task called refactoring. In software development, the purpose of refactoring is to rewrite parts of the code to enhance its robustness and clarity, to make it easier to maintain and re-usable in other contexts, without modifying its external functional behaviour (source: wikipedia). That is why end users should not notice a lot of changes appart from minor changes in the way it looks. But behind the curtains, it makes a big difference.
The whole visualization module is now fully compliant with the Model-View-Controller architecture in use in the most recent OTB applications. The initial limited set of classes has been splitted into several lighter classes and customization entry points have been carefully introduced in each critical part in order to provide maximum extensibility at minimal cost. Adding a new user interaction, a new type of curve to display or a new eyecandy object rendering onto the image is now as simple as rewriting a light class with about no code overhead.
The otbFeatureExtractionApplication was chosen to beta-test the refactored module, and was therefore modified to use the new visualization tool. Migrating the applications essentially involved removing hundreds of lines of code without compromising any of its functions, and therefore greatly improved its clarity, robustness and maintainabilty. We are already on the way to migrate other applications in order to make everyone benefit from the changes.
The otbFeatureExtractionApplication now uses the new visualization module
Using the new design, we also built a new overlay component to render the content of a shapefile or a kml file over an image in about no time.
Using the new design, a tool to quickly render vector data files (shapefile or kml) has been built
Of course, this does not extend the functionnal scope of the Orfeo ToolBox or its applications, but in the future, it will help us to reduce the cost and improve the robustness of new applications. Developping users will also find it easier to extend it to suit their needs. For further technical details, you might want to read the OTB wiki page on this topic, which includes a small tutorial to start using the new visualization module.
The International Charter aims at providing a unified system of space data acquisition and delivery to those affected by natural or man-made disasters through Authorized Users. Each member agency has committed resources to support the provisions of the Charter and thus is helping to mitigate the effects of disasters on human life and property.
The “Charter” was activated last week by the French Civil Protection for the wind storm and floods in the South-West of France. CNES, was Project Manager for this activation and the value added products were made by SERTIT.
OTB has been used in order to process some of the images acquired. Some change detection images (using ALOS/PALSAR, ENVISAT/ASAR and TerraSAR-X) were generated using OTB’s change detection framework.
The most interesting application of OTB was a supervised classification (using the otbSupervisedClassificationApplication) of a SPOT4 image in order to produce a flood mask.
Due to bad weather conditions, the SPOT4 image was difficult to handle.
SPOT4 image
As one can see, a major part of the flooded area is covered by translucid clouds. Segmentation by thresholding is very difficult. Manual extraction of the water bodies could take too long.
The supervised SVM classification helped a lot here. Less than 10 regions of interest were manually entered (using the otbSupervisedClassificationApplication). A simple linear SVM with the default parameters was used. The learning took 30 seconds, for an overall accuracy (on the test set) of nearly 100%. The classification of the whole scene took less than a minute (3000×3000 pixels in 4 bands). The result is shown here:
SVM classification
Well. This is a very good result from the image processer point of view. However, this is not the kind of thing that one can give to end users dealing with the crisis management.
This binary layer was made available to the expert interpreters from SERTIT. Using their experience in image interpretation, they could improve this product (reduce the false detections due to clouds and other artifacts). But all in all, the product helped saving time.
The final, professional looking map, which was sent to the users is here:
Map by SERTIT
As a conclusion, one can say that OTB helped in an operational context, although the production of good quality maps needs (and always will) human experts.
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