Visadapt: Catadioptric adaptive camera for scenes of variable density of visual information.

This paper presents the design method of a multi-resolution camera, named Visadapt. It is made of a conventional compact camera with a sensor and a lens pointed to a new deformable mirror so that the mirror in a flat state is parallel to the image plane. The main novelty of the latter mirror, to our knowledge, is the ability to control automatically strokes of several millimeters.

SofaGym: An Open Platform for Reinforcement Learning Based on Soft Robot Simulations.

OpenAI Gym is one of the standard interfaces used to train Reinforcement Learning (RL) Algorithms. The Simulation Open Framework Architecture (SOFA) is a physics-based engine that is used for soft robotics simulation and control based on real-time models of deformation. The aim of this article is to present , an open-source software to create OpenAI Gym interfaces, called environments, out of soft robot digital twins.

Blood vessel modeling for interactive simulation of interventional neuroradiology procedures.

Endovascular interventions can benefit from interactive simulation in their training phase but also during pre-operative and intra-operative phases if simulation scenarios are based on patient data. A key feature in this context is the ability to extract, from patient images, models of blood vessels that impede neither the realism nor the performance of simulation. This paper addresses both the segmentation and reconstruction of the vasculature from 3D Rotational Angiography data, and adapted to simulation: An original tracking algorithm is proposed to segment the vessel tree while filtering points extracted at the vessel surface in the vicinity of each point on the centerline; then an automatic procedure is described to reconstruct each local unstructured point set as a skeleton-based implicit surface (blobby model).

Monocular 3D Reconstruction and Augmentation of Elastic Surfaces with Self-Occlusion Handling.

This paper focuses on the 3D shape recovery and augmented reality on elastic objects with self-occlusions handling, using only single view images. Shape recovery from a monocular video sequence is an underconstrained problem and many approaches have been proposed to enforce constraints and resolve the ambiguities. State-of-the art solutions enforce smoothness or geometric constraints, consider specific deformation properties such as inextensibility or resort to shading constraints.

Impact of Soft Tissue Heterogeneity on Augmented Reality for Liver Surgery.

This paper presents a method for real-time augmented reality of internal liver structures during minimally invasive hepatic surgery. Vessels and tumors computed from pre-operative CT scans can be overlaid onto the laparoscopic view for surgery guidance. Compared to current methods, our method is able to locate the in-depth positions of the tumors based on partial three-dimensional liver tissue motion using a real-time biomechanical model.

Registration by interactive inverse simulation: application for adaptive radiotherapy.

Purpose: This paper introduces a new methodology for semi-automatic registration of anatomical structure deformations. The contribution is to use an interactive inverse simulation of physics-based deformable model, computed in real time.

Methods: The method relies on nonlinear finite element method (FEM) within a constraint-based framework.

Introducing interactive inverse FEM simulation and its application for adaptive radiotherapy.

We introduce a new methodology for semi-automatic deformable registration of anatomical structures, using interactive inverse simulations. The method relies on non-linear real-time Finite Element Method (FEM) within a constraint-based framework. Given a set of few registered points provided by the user, a real-time optimization adapts the boundary conditions and(/or) some parameters of the FEM in order to obtain the adequate geometrical deformations.

Towards a better understanding of pelvic system disorders using numerical simulation.

Genital prolapse is a pathologic hyper-mobility of the organs that forms the pelvic system. Although this is common condition, the pathophysiology of this disorder is not well known. In order to improve the understanding of its origins, we recreate--virtually--this biomechanical pathology using numerical simulation.

Deformation-based augmented reality for hepatic surgery.

In this paper we introduce a method for augmenting the laparoscopic view during hepatic tumor resection. Using augmented reality techniques, vessels, tumors and cutting planes computed from pre-operative data can be overlaid onto the laparoscopic video. Compared to current techniques, which are limited to a rigid registration of the pre-operative liver anatomy with the intra-operative image, we propose a real-time, physics-based, non-rigid registration.

Local implicit modeling of blood vessels for interactive simulation.

In the context of computer-based simulation, contact management requires an accurate, smooth, but still efficient surface model for the blood vessels. A new implicit model is proposed, consisting of a tree of local implicit surfaces generated by skeletons (blobby models). The surface is reconstructed from data points by minimizing an energy, alternating with an original blob selection and subdivision scheme.

Biomechanical simulation of electrode migration for deep brain stimulation.

Deep Brain Stimulation is a modern surgical technique for treating patients who suffer from affective or motion disorders such as Parkinson's disease. The efficiency of the procedure relies heavily on the accuracy of the placement of a micro-electrode which sends electrical pulses to a specific part of the brain that controls motion and affective symptoms. However, targeting this small anatomical structure is rendered difficult due to a series of brain shifts that take place during and after the procedure.

Towards interactive planning of coil embolization in brain aneurysms.

Many vascular pathologies can now be treated in a minimally invasive way thanks to interventional radiology. Instead of open surgery, it allows to reach the lesion of the arteries with therapeutic devices through a catheter. As a particular case, intracranial aneurysms are treated by filling the localized widening of the artery with a set of coils to prevent a rupture due to the weakened arterial wall.

Interactive simulation of embolization coils: modeling and experimental validation.

Coil embolization offers a new approach to treat aneurysms. This medical procedure is namely less invasive than an open-surgery as it relies on the deployment of very thin platinum-based wires within the aneurysm through the arteries. When performed intracranially, this procedure must be particularly accurate and therefore carefully planned and performed by experienced radiologists.

Interactive contacts resolution using smooth surface representation.

Accurately describing interactions between medical devices and anatomical structures, or between anatomical structures themselves, is an essential step towards the adoption of computer-based medical simulation as an alternative to traditional training methods. However, while substantial work has been done in the area of real-time soft tissue modeling, little has been done to study the problem of contacts occurring during tissue manipulation. In this paper we introduce a new method for correctly handling complex contacts between various combination of rigid and deformable objects.

[Evolution and transformation in animal organism of some polychlorobiphenyls (author's transl)].

Intoxication by pure polychlorobiphenyls and a commercial product is studied, in rats, after intraperitoneal and oral administration. Their fixation and excretion of their metabolites is greater by intraperitoneal than by oral administration. The only hydroxy metabolites, identified by means of synthesis, gas chromatography and mass spectrometry are, all, derivatives from trichlorobiphenyl.

[Experimental toxocologic study of some trichlorobiphenyl isomers].

The authors, after having performed the preparation of a few pure trichlorobiphenyl isomers, proceeded with a preliminary toxicological study of the rat which should then facilitate study for a commerical product. The fixation level of these compounds is considerably higher in lipids and in the spleen than in the other organs. Urinary elimination is very low compared with faecal excretion; furthermore, chromatographic analysis makes it possible to shed light on phenolic products of transformation in the excreta, some of which it was possible to identify with hydroxylated trichlorobiphenyls synthesized in the laboratory.