Optimal DLT-based Solutions for the Perspective-n-Point

We propose a modified normalized direct linear transform (DLT) algorithm for solving the perspective-n-point (PnP) problem with much better behavior than the conventional DLT. The modification consists of analytically weighting the different measurements in the linear system with a negligible increase in computational load. Our approach exhibits clear improvements -- in both performance and runtime -- when compared to popular methods such as EPnP, CPnP, RPnP, and OPnP. Our new non-iterative solution approaches that of the true optimal found via Gauss-Newton optimization, but at a fraction of the computational cost. Our optimal DLT (oDLT) implementation, as well as the experiments, are released in open source.

LOSTU: Fast, Scalable, and Uncertainty-Aware Triangulation

Triangulation algorithms often aim to minimize the reprojection ($L_2$) error, but this only provides the maximum likelihood estimate when there are no errors in the camera parameters or camera poses. Although recent advancements have yielded techniques to estimate camera parameters accounting for 3D point uncertainties, most structure from motion (SfM) pipelines still use older triangulation algorithms. This work leverages recent discoveries to provide a fast, scalable, and statistically optimal way to triangulate called LOSTU. Results show that LOSTU consistently produces lower 3D reconstruction errors than conventional $L_2$ triangulation methods -- often allowing LOSTU to successfully triangulate more points. Moreover, in addition to providing a better 3D reconstruction, LOSTU can be substantially faster than Levenberg-Marquardt (or similar) optimization schemes.

Towards a more efficient use of process and product traceability data for continuous improvement of industrial performances

Nowadays all industrial sectors are increasingly faced with the explosion in the amount of data. Therefore, it raises the question of the efficient use of this large amount of data. In this research work, we are concerned with process and product traceability data. In some sectors (e.g. pharmaceutical and agro-food), the collection and storage of these data are required. Beyond this constraint (regulatory and / or contractual), we are interested in the use of these data for continuous improvements of industrial performances. Two research axes were identified: product recall and responsiveness towards production hazards. For the first axis, a procedure for product recall exploiting traceability data will be propose. The development of detection and prognosis functions combining process and product data is envisaged for the second axis.