Electronic device for processing image-data, for simulating the behaviour of a deformable object

An improved electronic process for processing image data, of the type that includes the steps of

• providing a user interface (4) capable of generating a force feedback, in accordance with the reactions of a tool (6, 7),
• establishing, on the basis of a deformation law and of an action defined by the user interface (4) and representative of a maneuver of the said tool, a field of internal forces between nodes of a volume meshing dependent on a surface meshing of a 3D object appearing in a set of image data, wherein the volume meshing includes links between the nodes thereof, and additionally includes mesh cells that are defined by the nodes and the links,
• determining the reaction force of the object which corresponds to its deformation estimated on the basis of the internal forces, so that the force generated by the user interface (4) is substantially balanced by this reaction force, and
• calculating new image data of the object, in the presence of the estimated deformations supplemented with the representation of the said tool,
• wherein the improvement comprises:
• estimating a point of intersection between a straight line embodying a displacement derived from the said defined action and the said surface meshing is estimated, and
• estimating the internal force exerted on the nodes of a first part at least of the volume meshing of the object, on the basis of the displacement applied to the nodes belonging to the surface mesh cell containing the said point of intersection, of boundary conditions, and of node tensors and link tensors emanating respectively for each node and each link of this part at least, from stiffness matrices specific to each volume mesh cell of at least the said first part and dependent on the deformation law.

An improved method for permitting a user to manipulate a 3D virtual object with the aid of a user interface that senses movement of a tool by the user and that provides force feedback to the user, the virtual object appearing in a set of image data and having a surface meshing and a volume meshing, said method being of the type that includes

• establishing, on the basis of a deformation law, a field of internal forces between nodes of the volume meshing when the virtual object is deformed by the tool;
• determining a reaction force that is to be exerted by the user interface when the virtual object is deformed by the tool, the deformation of the virtual object being estimated at least in part on the basis of the internal forces;
• and
• calculating new image data of the object, in the presence of the estimated deformation supplemented with a representation of the tool;
• wherein the improvement comprises:
• estimating a point of intersection between a straight line embodying a displacement of the tool and the surface meshing,
• wherein the internal force exerted on the nodes of a part of at least the volume meshing of the virtual object is estimated on the basis of at least one factor, the at least one factor including a displacement applied to the nodes belonging to a surface mesh cell containing the point of intersection.