Simulation studies and practical tests using multi-image shape from shading

Multi-image shape from shading (MI-SFS) is a surface reconstruction method, which has been studied intensively by our group over the last years. Our goal is to develop a method incorporating MI-SFS and image matching for use in planetary science. MI-SFS directly relates the grey values of one or more images to the heights of a digital terrain model (DTM) and the parameters of a radiometric surface model, which describes the surface reflectance behaviour. The DTM heights as well as the parameters of the radiometric model are estimated from the image grey values in a least squares adjustment. In this paper, we shortly review the principles of MI-SFS and analyse its characteristics using theoretical investigations and a practical example. Throughout the text, a comparison of two widely used reflectance models in planetary science, the well-known Lambert and the Lommel-Seeliger reflectance models, is given together with an investigation into the pros and cons of using more than one image and, thus, of MI-SFS compared to classical SFS. Results from a practical test using digitised aerial images are described, which demonstrate the potential of MI-SFS and its advantages over single image SFS.