OTB News – September 2020

We realize it has been a long time since last release which was OTB version 7.1, 6 months ago. We have been pretty busy working on a deep refactoring aiming at removing the OSSIM library from OTB’s dependencies.

Removing OSSIM dependency

This is an extended work that implies some changes in the library’s API and the migration of some complex components. But this work brings substantial advantages. First, more simplicity for the installation and compilation with the removal of 3 mandatory dependencies (OSSIM, OssimPlugins, OpenThreads) and 2 modules (OTBOssimAdapters and OTBOpenThreadsAdapters). Secondly, easier support of new sensors models and a well separated metadata architecture which allows better metadata processing in our pipelines. This work will be part of the OTB 8.0 that should be released before Christmas.

A note of warning for users of the develop branch: since the version 8.0 will bring deep changes in the metadata management, the develop branch is in a transition phase with parts of the toolbox that may not function as expected.

Currently, the new metadata mechanism is merged into develop and functional. But the ImageMetadataInterfaces classes (IMI), which are in charge of the reading and the writing of the metadata is a work in progress. The IMI for the optical sensors are being implemented now. The IMI for the SAR sensor are planned for next month.

A new DEMHandler class is also merged into develop. It replaces OSSIM’s DEM handler, and is based on GDAL. The new architecture for sensor models should follow soon, with a new implementation of the RPC model, also based on GDAL. Finally, the SAR sensor model functionalities provided by OSSIM will be moved to the new architecture.

A minor release is coming

In the mean time, we prepare a minor release 7.2. The release candidate should arrive in the coming weeks. More details about this release will come in a specific communication.

Coming soon: S1Tiling remote module

The S1Tiling team proposes to integrate their remote module as an official OTB remote module. They are currently working on that integration. The purpose of this module is to processes Ortho-rectification of Sentinel-1 data on Sentinel-2 grid. It comes with some interesting features that are being integrated directly in the OTB, such as the ResetMargins application.