Earth observation data is becoming increasingly important for our understanding of the planet and for addressing socio-ecological challenges – for example, in environmental monitoring. Methods for data acquisition and processing from space are currently limited by long acquisition times (up to several days per measurement), low spatial resolution (about 1 km), and the usable spectral range (primarily in the visible). Novel camera systems based on spatial light modulators can provide a remedy here. These are being realized and tested for the first time within the EU project SURPRISE. Fraunhofer IPMS contributes with its long-standing expertise with spatial light modulators and plans to develop a spatial light modulator suitable for space applications.
The main goal of the project is to develop a demonstrator. Core parameters include spectrally broadband operating range – in the visible (VIS), near-infrared (NIR), and mid-infrared (MIR) – improved performance in terms of ground resolution, and innovative on-board data processing and encryption functionality. Innovative Compressive Sensing (CS) technology is used for this purpose. It allows a two-dimensional image to be captured using a single-pixel detector. This is particularly interesting for the mid-infrared because no suitable 2D detectors are available in this spectral range. Compressive Sensing also offers advantages in processing large amounts of data as well as native data encryption.
The special CS imaging technology used in the project for Earth observation requires special components. Spatial light modulators are the most suitable solution for this task because variable image patterns can be generated at high speed. These patterns are overlaid with the observation scene and recorded by single pixel detectors. The spatial light modulators developed by Fraunhofer IPMS consist of thousands – or even millions – of individual movable mirrors, each only a few micrometers in size. Fraunhofer IPMS uses its extensive experience in the development and manufacture of spatial light modulators in order to find the best solution for the specific requirements in the project. The biggest challenges here are the space capability of all components and the coverage of a broad spectral range from visible to mid-infrared.
Fraunhofer IPMS leads the activities in the project regarding the spatial light modulators. The main tasks are to contribute to demonstrator development and to prepare a feasibility study and development road map for a first space-qualified spatial light modulator (SLM) developed entirely in Europe.