Basic information
Original title:
Automatic generation of true orthoimages from very high-resolution data
1 May 2017–30 April 2019

Remote sensing data is becoming an increasingly important source for supplementing existing geospatial data, or even upgrading it. Due to the high quantity of new and existing data the automation of its processing has become very important, as only (semi)automatic processes can provide large quantities of end products in near real time.

In this respect, a special attention should be given to the very high-resolution (VHR) optical satellite data. Its best resolution (currently 0.3 m) is already comparable to the resolution of aerial images, usage application areas are almost identical. However, since no automated procedures for their processing that would provide sufficiently accurate and high-quality products are available, their potential is still not completely exploited.

Before optical satellite imagery can be used for spatial analysis, combined with a variety of other geo-referenced data, they have to be orthorectified into so-called orthoimages. Orthoimages have a high usability, since they contain both image characteristics of a photograph and geometric properties of a topographic map. Nowadays orthoimages are indispensable in particular as a raster basis for a variety of geospatial applications. They can replace or complement vector data or generate geodetic data for the purpose of planning.

True orthoimages are an improved version of traditional orthoimages as they are adjusted also for high objects (e.g. high buildings). Generation of true orthoimages is more complex than the generation of usual orthoimages, since it requires more images of the same area, acquired from different angles (the so-called image block).

The aim of the research project is to develop an automatic procedure for orthorectification of VHR satellite images, and generation of traditional orthoimages or true orthoimages in a very short time. The results can be used directly by end-users for the production of spatial data or in GIS analyses.

The project deals with a research topic that will bring many innovations in the field of remote sensing and will also have a big potential for application in other scientific fields. The extensive analyses that are going to be performed will enable the transfer of knowledge to actual systems or databases that will be used by potential public or private end-users. The project is harmonized with the needs and demands of current project calls, published by European Space Agency and European Union.

By achieving the project goals, we expect significant advances when compared to the existing approaches in the field of automatic true orthoimage generation from satellite data. With the specific knowledge gained, the Slovenian expertise will contribute to the development of the newest research in this field.

    Project steps

    Most of the project phases will be carried out successively, from the first to the last work package. They represent complete units, but are also strongly connected. The proposed project is organized in five work packages (the work package in bold text is currently under development):

    • WP1: Automatic extraction of ground control points (GCPs) from VHR images,
    • WP2: Geometric model for satellite images processing,
    • WP3: Direct orthorectification for the generation of true orthoimages,
    • WP4: Generation of true orthoimages, and
    • WP5: Automation, optimisation and validation of developed procedures.

    Lead partner

    Project manager

    Project manager at ZRC

    Funded by

    Slovenian Research Agency


    automatic processing • satellite images • orthorectification • true orthoimage • high-resolution surface model • geometric modelling