Fast and Accurate Depth Estimation from Sparse Light Fields

We present a fast and accurate method for dense depth reconstruction from sparsely sampled light fields obtained using a synchronized camera array. In our method, the source images are over-segmented into non-overlapping compact superpixels that are used as basic data units for depth estimation and refinement. Superpixel representation provides a desirable reduction in the computational cost while preserving the image geometry with respect to the object contours. Each superpixel is modeled as a plane in the image space, allowing depth values to vary smoothly within the superpixel area. Initial depth maps, which are obtained by plane sweeping, are iteratively refined by propagating good correspondences within an image. To ensure the fast convergence of the iterative optimization process, we employ a highly parallel propagation scheme that operates on all the superpixels of all the images at once, making full use of the parallel graphics hardware. A few optimization iterations of the energy function incorporating superpixel-wise smoothness and geometric consistency constraints allows to recover depth with high accuracy in textured and textureless regions as well as areas with occlusions, producing dense globally consistent depth maps. We demonstrate that while the depth reconstruction takes about a second per full high-definition view, the accuracy of the obtained depth maps is comparable with the state-of-the-art results.Comment: 15 pages, 15 figure

Potential of terrestrial laserscanning in load test measurements of bridges

The state-of-the-art geodetic and remote sensing techniques can prove their potential through particular engineering applications. Besides the traditional surveying terrestrial laserscanning broadens its application field in civil engineering projects. The Department of Photogrammetry and Geoinformatics has long experience in the measurement methods, accuracy analysis and applications of terrestrial laserscanning. This paper deals with the potential of the technology through the examples of load test measurements of Danube bridges. Prior to the particular bridge surveying projects accuracy analysis has been carried out in laboratory measurements, the results validated the accuracy and reliability of the laserscanned data. The paper discusses the complex measurement procedure, the main steps of the data processing and results. Remote sensing can provide data about specific (e.g. with limited accessibility) areas of the structure that cannot be measured with traditional techniques during the short period of the load test measurements. The post-processing includes comparison analysis using ground-based geodetic measurements (such as high precision leveling) as reference in defining displacements. By computing the accuracy measures of the terrestrial laserscanning the overall technology can be qualified and calibrated

Remote sensing data quality model: from data sources to lifecycle phases

ABSTRACTThe importance of data quality assessment has significantly increased with the boom of information technology and the growing demand for remote sensing (RS) data. The Remote Sensing Data Qu..

Expert evaluation of a novel light-field visualization format

Light-field visualization is continuously emerging in industrial sectors, and the appearance on the consumer market is approaching. Yet this process is halted, or at least slowed down, by the lack of proper display-independent light-field formats. Such formats are necessary to enable the efficient interchange between light-field content creation and visualization, and thus support potential future use case scenarios of this technology. In this paper, we introduce the results of a perceived quality assessment research, performed on our own novel light-field visualization format. The subjective tests, which compared conventional linear camera array visualization to our format, were completed by experts only, thus quality assessment was an expert evaluation. We aim to use the findings gathered in this research to carry out a large-scale subjective test series in the future, with non-expert observers