Abstract: Shape measurement of a specular object even in the presence of multiple intra-object reflections such as those at concave regions of the object. Silhouettes of the object are extracted, by positioning the object between a camera and a background. A visual hull of the object is reconstructed based on the extracted silhouettes, such as by image capture of shadows of the object projected onto a screen, and image capture of reflections by the surface of the object of coded patterns onto the screen. The visual hull is used to distinguish between direct (single) reflections of the coded patterns at the surface of the object and multiple reflections. Only the direct (single) reflections are used to triangulate camera rays and light rays onto the surface of the object, with multiple reflections being excluded. The 3D surface shape may be derived by voxel carving of the visual hull, in which voxels along the light path of direct reflections are eliminated.

Abstract: A system includes cameras; a rotating stage, which has an axis of rotation; one or more computer-readable media; and one or more processors that are coupled to the one or more computer-readable media, the rotating state, and the cameras. Also, the one or more processors are configured to cause the system to control the cameras to capture respective images of a calibration target in a first pose, wherein the calibration target is mounted on the rotating stage; control the rotating stage to rotate through a predetermined angular increment to a second pose; control the cameras to capture respective images of the calibration target in the second pose; and calculate a transformation between two of the cameras based on the respective images of the calibration target in the first pose, on the respective images of the calibration target in the second pose, and on the predetermined angular increment.

Abstract: Shape measurement of a specular object even in the presence of multiple intra-object reflections such as those at concave regions of the object. Silhouettes of the object are extracted, by positioning the object between a camera and a background. A visual hull of the object is reconstructed based on the extracted silhouettes, such as by image capture of shadows of the object projected onto a screen, and image capture of reflections by the surface of the object of coded patterns onto the screen. The visual hull is used to distinguish between direct (single) reflections of the coded patterns at the surface of the object and multiple reflections. Only the direct (single) reflections are used to triangulate camera rays and light rays onto the surface of the object, with multiple reflections being excluded. The 3D surface shape may be derived by voxel carving of the visual hull, in which voxels along the light path of direct reflections are eliminated.

Abstract: A system includes cameras; a rotating stage, which has an axis of rotation; one or more computer-readable media; and one or more processors that are coupled to the one or more computer-readable media, the rotating state, and the cameras. Also, the one or more processors are configured to cause the system to control the cameras to capture respective images of a calibration target in a first pose, wherein the calibration target is mounted on the rotating stage; control the rotating stage to rotate through a predetermined angular increment to a second pose; control the cameras to capture respective images of the calibration target in the second pose; and calculate a transformation between two of the cameras based on the respective images of the calibration target in the first pose, on the respective images of the calibration target in the second pose, and on the predetermined angular increment.

Abstract: An endovascular platform is provided that includes a periodic tiling-based stent structure having a parallelogram tile associated with a fundamental domain and an intrinsic cell-shape. A lattice vector includes a section of the parallelogram tile where the lattice vector is circumferentially folded to create helical repetition of cells.