Patent ID: 11893690
Assignee: DASSAULT SYSTEMES
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 15:
16. A system comprising:
a processor coupled to a memory and a graphical user interface, the memory having recorded thereon a computer program for 3D reconstruction that when executed by the processor causes the processor to be configured to:
obtain 2D images which all represent a same real object which is fixed, and, for each 2D image, camera parameters which define a perspective projection,
obtain, for each 2D image, a smooth map, the smooth map having pixel values each representing a measurement of contour presence, the contour being a location of separation between two different textures of the 2D image, the smooth map including local extrema corresponding to contour probability maxima, an energy rewarding high contour probability at projections of silhouette vertices, the smooth map varying from values representing a respective zero contour probability to the local extrema, the smooth map having non-zero gradients at least in a vicinity of image contours, a gradient of the smooth map being thereby non-zero at pixels corresponding to zero contour probability, the smooth map locally varying monotonously towards local optima and presenting C0 continuity, and
determine a 3D modeled object that represents the real object, the determining iteratively optimizing an energy that rewards, for each smooth map, projections of silhouette vertices of the 3D modeled object having pixel values, on the smooth map, representing a high measurement of contour presence, the optimization iteratively following a monotonous gradient path on the smooth map,
wherein the processor is further configured to, at each iteration of the optimizing:
obtain a current first mesh, which is a control mesh;
obtain a current second mesh, the current second mesh being obtained by subdividing the current first mesh;
for each 2D image:
project the current second mesh on the 2D image;
compute a 2D silhouette of the 3D modeled object in the 2D image; and
identify points of the current second mesh corresponding to the 2D silhouette, as the silhouette vertices; and

modify the current first mesh to reduce the energy, the modified current first mesh of each respective iteration having a next iteration being the current first mesh of the next iteration, the current second mesh of the next iteration thereby having different coordinates of vertices from the current second mesh of the respective iteration.