Laurent Ott

Robotic Assistance to Flexible Endoscopy by Physiological-Motion Tracking

Flexible endoscopes are used in many diagnostic exams, like gastroscopies or colonoscopies, as well as for small surgical procedures. Recently, they have also been used for endoscopic surgical procedures through natural orifices [natural orifice transluminal endoscopic surgery (NOTES)] and for single-port-access abdominal surgery (SPA). Indeed, flexible endoscopes allow access of operating areas that are not easily reachable with only one small external or internal incision. However, their manipulation is complex, especially for surgical interventions. This study proposes to motorize the flexible endoscope and to partly robotize its movements in order to help the physicians during such interventions. The paper explains how the robotized endoscope can be used to automatically track an area of interest despite breathing motion. The system uses visual servoing and repetitive control strategies and allows stabilization of the endoscopic view. All required parameters are automatically estimated. In vivo experiments show the validity of the proposed solution for the improvement of the manipulation of flexible endoscopes.

Physiological motion rejection in flexible endoscopy using visual servoing

Flexible endoscopes are used in many surgical procedures and diagnostic exams, like in gastroscopy or coloscopy. They have also been used recently for new surgical procedures using natural orifices called NOTES. While these procedures are very promising for the patients, they are quite awkward for the surgeons. The flexible endoscope allows the access to operating areas which are not easily reachable, with small or no incisions; but the manipulation of the system is complex. In order to help the practicians during NOTES or classical interventions with flexible endoscopes, we propose to motorize the system so as to partially robotize the movements. This paper presents the problems in the use of the flexible endoscope and explains how the system can be used to stabilize the endoscope on an area of interest despite physiological motions and therefore to improve the manipulation of the system.

Effects of emotion regulation difficulties on the tonic and phasic cardiac autonomic response.

Background Emotion regulation theory aims to explain the interactions between individuals and the environment. In this context, Emotion Regulation Difficulties (ERD) disrupt the physiological component of emotions through the autonomic nervous system and are involved in several psychopathological states. Objective We were interested in comparing the influence of a film-elicited emotion procedure on the autonomic nervous system activity of two groups with different levels of emotion regulation difficulties. Methods A total of 63 women (undergraduate students) ranging from 18 to 27 (20.7±1.99) years old were included. Using the upper and lower quartile of a questionnaire assessing the daily difficulties in regulating emotions, two groups, one with low (LERD) and one with high (HERD) levels of emotion regulation difficulties, were constituted and studied during a film-elicited emotion procedure. Cardiac vagal activity (HF-HRV) was analyzed during three periods: baseline, film-elicited emotion, and recovery. Results The cardiovascular results showed a decrease in HF-HRV from baseline to elicitation for both groups. Then, from elicitation to recovery, HF-HRV increased for the LERD group, whereas a low HF-HRV level persisted for the HERD group. Conclusions The HERD group exhibited inappropriate cardiac vagal recovery after a negative emotion elicitation had ended. Cardiac vagal tone took longer to return to its initial state in the HERD group than in the LERD group. Prolonged cardiac vagal suppression might constitute an early marker of emotion regulation difficulties leading to lower cardiac vagal tone.

Joystick Interfaces Are Not Suitable for Robotized Endoscope Applied to NOTES

Background NOTES has changed the working environment of endoscopy, leading to new difficulties. The limitations of conventional endoscopes call for the development of new platforms. Robotics may be the answer. Materials and methods The authors compared human to robotized manipulation of a flexible endoscope into the abdominal cavity, in an animal model. Thirty-two participants were enrolled. Results were analyzed according to the clinical background of the participants: experienced endoscopists, experienced laparoscopists, and medical students. Two single-channel gastroscopes were used. Whereas one was not modified, the other had the handling wheels replaced by motors controlled through a computer and a joystick. A NOTES transgastric approach was used to access the peritoneal cavity. The time to touch previously positioned intra-abdominal numbered plastic targets was recorded 3 times with each endoscope. Results Mean time to complete the tasks was significantly shorter using the conventional endoscope (2.71 vs 6.96 minutes, P < .001). When the robotized endoscope was used, the mean times of endoscopists (7.42 minutes), laparoscopists (6.84 minutes), and students (6.77 minutes) were statistically identical. No differences were found between laparoscopists and students in both techniques. Discussion Applying robotics to a flexible endoscope fails to enhance ability to move into the abdominal cavity, partly because of the interface. To overcome the limitations of endoscope when performing complex NOTES tasks, robotics may be useful, especially to control the instruments and to stabilize the endoscope itself. Conclusion Robotized endoscope with joystick interface is not sufficient to enhance immediate intuitiveness of flexible endoscopy applied to NOTES.

Animation Movie Abstraction: Key Frame Adaptative Selection Based on Color Histogram Filtering

This paper deals with the construction of animation movie abstracts. The proposed video abstracts are computed using an adaptive selection of key frames obtained by color histogram analysis. The method exhibits three main parts. In the first step, a shot detection is performed. Then, within each shot, an adaptive number of key frames is selected. This selection is performed by analyzing cumulative distances between frame color histograms. In the third step, an inter-shot examination is performed. Using an iterative selection we provide a user-specified number of movie representative frames. The method has been tested on a database from the International Animated Film Festival that takes place yearly in Annecy.

Physiological motion rejection in flexible endoscopy using visual servoing and repetitive control : Improvements on non-periodic reference tracking and non-periodic disturbance rejection

Flexible endoscopes are used in many surgical procedures and diagnostic exams, like in gastroscopy or coloscopy. They have also been used recently for new surgical procedures using natural orifices called NOTES. While these procedures are very promising for the patients, they are quite awkward for the surgeons. The flexible endoscope allows the access to operating areas which are not easily reachable, with small or no incisions; but the manipulation of the system is complex. In order to help the practicians during NOTES or classical interventions with flexible endoscopes, we propose to motorize the system so as to partially robotize the movements. This paper presents the problems in the use of the flexible endoscope and explains how the system can be used to stabilize the endoscope on an area of interest despite physiological motions and therefore to improve the manipulation of the system.

Animation movies trailer computation

This paper presents a method for the automatic generation of animation movie trailers. First, the movie is divided into shots, by detecting the video transitions (cuts, fades and dissolves) and an animation movie specific color effect named short color change or SCC (i.e. explosions, thunders). The movie action content is further highlighted by analyzing the movie at two different granularity levels. First, an inter-shot analysis is performed by measuring the video transition temporal distribution. As repetitive shot changes are related to action, we define as an action shot, a movie segment containing a high shot change ratio. On the other hand, an inter-frame analysis is performed: for each shot within an action shot, an histogram of cumulative inter-frame distances is computed to serve as a measure of the frame spatial activity. Repetitive color changes are also related to action. Since movie trailers only show some of the most attractive movie scenes, the proposed trailer is a moving-image abstract computed on the retained action shots. It provides the user with a compact and efficient representation of the movie action content. The proposed approach was tested on several animation movies.

A simple technique to study embodied language processes: the grip force sensor

Research in cognitive neuroscience has shown that brain structures serving perceptual, emotional, and motor processes are also recruited during the understanding of language when it refers to emotion, perception, and action. However, the exact linguistic and extralinguistic conditions under which such language-induced activity in modality-specific cortex is triggered are not yet well understood. The purpose of this study is to introduce a simple experimental technique that allows for the online measure of language-induced activity in motor structures of the brain. This technique consists in the use of a grip force sensor that captures subtle grip force variations while participants listen to words and sentences. Since grip force reflects activity in motor brain structures, the continuous monitoring of force fluctuations provides a fine-grained estimation of motor activity across time. In other terms, this method allows for both localization of the source of language-induced activity to motor brain structures and high temporal resolution of the recorded data. To facilitate comparison of the data to be collected with this tool, we present two experiments that describe in detail the technical setup, the nature of the recorded data, and the analyses (including justification about the data filtering and artifact rejection) that we applied. We also discuss how the tool could be used in other domains of behavioral research.

Tackling action-based video abstraction of animated movies for video browsing

We address the issue of producing automatic video abstracts in the context of the video indexing of animated movies. For a quick browse of a movies visual content, we propose a storyboard-like summary, which follows the movies events by retaining one key frame for each specific scene. To capture the shots visual activity, we use histograms of cumulative interframe distances, and the key frames are selected according to the distribution of the histograms modes. For a preview of the movies exciting action parts, we propose a trailer-like video highlight, whose aim is to show only the most interesting parts of the movie. Our method is based on a relatively standard approach, i.e., highlighting action through the analysis of the movies rhythm and visual activity information. To suit every type of movie content, including predominantly static movies or movies without exciting parts, the concept of action depends on the movies average rhythm. The efficiency of our approach is confirmed through several end-user studies.

Simultaneous Physiological Motion Cancellation and Depth Adaptation in Flexible Endoscopy

Flexible endoscopes are used in many surgical procedures and diagnostic exams. They have also been used recently for new surgical procedures using natural orifices called NOTES. While these procedures are really promising for the patients, they are really awkward for the surgeons. In order to assist the surgeon, physiological motion cancellation has been successfully applied on a robotized endoscope in [8]. However, the stability and performance of the involved controller were ensured only on a small working area, thus preventing the surgeon to manually move the endoscope during motion rejection. We propose in this paper to improve the physiological motion rejection despite depth changes due to the manual manipulation of the system. For this purpose, the complete model of the system is developed and an adaptive predictive controller based on depth estimation is proposed. The validity of the approach is demonstrated in in vitro experiments.