More than two thirds of our planet are covered with water. Nevertheless, we know more about the surface of the moon than about life in the oceans. The importance of the latter as a space for living and economy has been constantly increasing during the last years. Underwater recordings are commercially applied in the production of high-end multimedia material for education and entertainment, in the design, running and supervision of underwater buildings (pipelines, underwater structures of offshore wind power plants etc.), in the course of civil and military supervision, and also in marine biology and aquaculture. Furthermore, there is a growing demand in the private sector, e.g. from non-professional divers.
Compared to photography and filming on land underwater recordings are much more challenging:
The technical equipment for recording and lighting has to be waterproof and – depending on depth – tolerate high pressure.
The optical properties of water lead to a strong attenuation of light, and as depth increases especially the red parts of light are absorbed.
Floating particles in the water, as occurring e. g. in the Baltic Sea, result in poor sight and extremely grainy pictures.
The different light refraction in the transition areas of water, glass and air leads to optical distortion and unwanted enlargement.
The project aims at examining procedures for an efficient production, processing and analysis of underwater videos. In order to obtain a high quality the manual effort for preparation and follow-up of (if necessary stereo) underwater filming is rather high. This is to be considerably reduced. A concept has to be created taking into consideration the physical effects during underwater filming and thus achieving the highest possible quality – from recording up to presentation and analysis.
The project includes the following topics:
Optimal stereo recording under water (photos and video) with flexible stereo basis (new underwater camera)
Automated enhancement of the single images with the focus on color correction, noise reduction and sharpness (software modules for the processing of underwater recordings)
Automated enhancement of the video recordings with the focus on color correction, noise reduction and sharpness (software modules for the processing of underwater recordings)
3D reconstruction from underwater stereo images and sequences (software modules for the analysis of underwater recordings)
Research focus of Fraunhofer IGD
We prototypically develop new approaches to automatic image improvement of underwater recordings and systematically test them. In this course we apply innovative procedures which allow efficient editing of underwater images with best results.
Automatic image improvement encompasses the improvement of contrast, to improve textures, and colors, to counteract the loss of color with increasing depth.
Color improvement is to be supported by information from 3D reconstruction. This model-based approach is one of the main innovations of the project. As absorption of the different wave lengths of light depends on the source of light and also on the distance between the respective object and the camera, additional information about these states can be very useful in the course of the improvement process.
In the project we will make use of 3D stereo depth, which can be calculated by a stereo camera system. In order to express it in metrical units the stereo camera system has to be calibrated. Due to light refraction common calibration procedures under water are not suitable.
In this project we cooperate with PINKAU Interactive Entertainment GmbH.