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Simon Léonard

dblp:04/1594 · DBLP profile ↗
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28ranked-venue papers
10as first author
2since 2021 · last 2023
0000-0001-6429-4755ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 24 · 9 first-author · 2 since 2021Systems, architecture and hardware · 23 · 8 first-author · 2 since 2021Applied, interdisciplinary, general and emerging computing · 4 · 1 first-authorGraphics, computer vision, multimedia, augmented reality and games · 2

Expertise — from the expertise taxonomy: the topics of the expert's papers under the CCF categories. A weight counts papers with recency: 1 for a paper about the topic, 0.3 when the topic is its context, halved every five years.

Artificial intelligence
15 papers
Motion planning and robot control · 42% Robot manipulation · 24% 3D vision · 16%
Human-computer interaction and pervasive computing
3 papers
Human-robot interaction · 96% Haptics and multimodal interaction · 4%
Computer graphics and multimedia
3 papers
Virtual and augmented reality · 100%
Interdisciplinary, comprehensive, and emerging computing
4 papers
Medical and health informatics · 100%

Topics — the 24 heaviest of 26, each with the papers that count most for it

TopicWeightPapersLastEvidence papers
Human-robot interaction
teleoperation
1.332023
A Virtual Reality Planning Environment for High-Risk, High-Latency Teleoperation · ICRA 2023
Experimental Evaluation of Teleoperation Interfaces for Cutting of Satellite Insulation · ICRA 2019
Experimental evaluation of force control for virtual-fixture-assisted teleoperation for on-orbit manipulation of satellite thermal blanket insulation · ICRA 2015
Virtual and augmented reality › immersive interaction › 3d user interfaces
virtual reality interface
0.712023
A Virtual Reality Planning Environment for High-Risk, High-Latency Teleoperation · ICRA 2023
Medical and health informatics
surgical robotics
0.632018
Semi-Autonomous Laparoscopic Robotic Electro-Surgery with a Novel 3D Endoscope * Research reported in this paper was supported by National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under award numbers 1R01EB020610 and R21EB024707. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health · ICRA 2018
Plenoptic cameras in surgical robotics: Calibration, registration, and evaluation · ICRA 2016
Smart Tissue Anastomosis Robot (STAR): Accuracy evaluation for supervisory suturing using near-infrared fluorescent markers · ICRA 2014
Virtual and augmented reality › mixed reality
augmented virtuality
0.412019
Experimental Evaluation of Teleoperation Interfaces for Cutting of Satellite Insulation · ICRA 2019
Human-robot interaction › teleoperation
teleoperation interface
0.412019
Experimental Evaluation of Teleoperation Interfaces for Cutting of Satellite Insulation · ICRA 2019
Robotics › Motion planning and robot control
robot control
0.322018
Model-based telerobotic control with virtual fixtures for satellite servicing tasks · ICRA 2013
Semi-Autonomous Laparoscopic Robotic Electro-Surgery with a Novel 3D Endoscope * Research reported in this paper was supported by National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under award numbers 1R01EB020610 and R21EB024707. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health · ICRA 2018
Computer vision › 3D vision › range sensing
depth sensing
0.212016
Plenoptic cameras in surgical robotics: Calibration, registration, and evaluation · ICRA 2016
Medical and health informatics › surgical robotics
robot-assisted surgery
0.212016
Plenoptic cameras in surgical robotics: Calibration, registration, and evaluation · ICRA 2016
Robotics › Motion planning and robot control › robot control
force control
0.212015
Experimental evaluation of force control for virtual-fixture-assisted teleoperation for on-orbit manipulation of satellite thermal blanket insulation · ICRA 2015
Virtual and augmented reality
augmented reality
0.212015
Registration of planar virtual fixtures by using augmented reality with dynamic textures · ICRA 2015
Knowledge, reasoning and agents › Planning, search and constraint satisfaction
interactive planning
0.212023
A Virtual Reality Planning Environment for High-Risk, High-Latency Teleoperation · ICRA 2023
Robotics › Motion planning and robot control
motion planning
0.222010
Path Planning for Improved Visibility Using a Probabilistic Road Map · IEEE Trans. Robotics 2010
Dynamic visibility checking for vision-based motion planning · ICRA 2008
Robotics › Motion planning and robot control
robot learning
0.232007
On with the Visuomotor Function: A 6DOF Adaptive Approach for Modeling Image-Based Variations and Visual Servoing · ICRA 2007
Adaptive Control for Estimating Translations from Image-based Variations · ICRA 2006
Incremental Learning for Mapping Image Variations to Actions · ICRA 2005
Robotics › Motion planning and robot control › robot control › compliant motion control
hybrid position/force control
0.212013
Model-based telerobotic control with virtual fixtures for satellite servicing tasks · ICRA 2013
Computer vision › 3D vision
3d scene understanding
0.112012
Sequential scene parsing using range and intensity information · ICRA 2012
Computer vision › 3D vision
object pose estimation
0.112012
Sequential scene parsing using range and intensity information · ICRA 2012
Computer vision › Image recognition and object detection
object recognition
0.112012
Sequential scene parsing using range and intensity information · ICRA 2012
Computer vision › Segmentation and scene understanding
scene parsing
0.112012
Sequential scene parsing using range and intensity information · ICRA 2012
Robotics › Motion planning and robot control › motion planning › sampling-based motion planning
probabilistic roadmap
0.112010
Path Planning for Improved Visibility Using a Probabilistic Road Map · IEEE Trans. Robotics 2010
Robotics › Motion planning and robot control › motion planning › geometric motion planning
visibility-based planning
0.112010
Path Planning for Improved Visibility Using a Probabilistic Road Map · IEEE Trans. Robotics 2010
Robotics › Robot navigation and mapping
visual navigation
0.142008
Dynamic visibility checking for vision-based motion planning · ICRA 2008
On with the Visuomotor Function: A 6DOF Adaptive Approach for Modeling Image-Based Variations and Visual Servoing · ICRA 2007
Adaptive Control for Estimating Translations from Image-based Variations · ICRA 2006
Robotics › Motion planning and robot control › robot control › sensor-based control
visual servoing
0.142008
Dynamic visibility checking for vision-based motion planning · ICRA 2008
On with the Visuomotor Function: A 6DOF Adaptive Approach for Modeling Image-Based Variations and Visual Servoing · ICRA 2007
Adaptive Control for Estimating Translations from Image-based Variations · ICRA 2006
Robotics › Motion planning and robot control
teleoperation
0.112015
Registration of planar virtual fixtures by using augmented reality with dynamic textures · ICRA 2015
Haptics and multimodal interaction › haptic feedback
force feedback
0.112015
Experimental evaluation of force control for virtual-fixture-assisted teleoperation for on-orbit manipulation of satellite thermal blanket insulation · ICRA 2015

Methods — techniques the papers use, named apart from their topics

user study · 2.4robotic pick-place-decapitate · 1.0computer vision · 1.0human subject study · 0.8structured light · 0.73d endoscope reconstruction · 0.7metric calibration · 0.5hand-eye calibration · 0.5optical flow · 0.4dynamic texturing · 0.4human-subject study · 0.4stereo vision · 0.2force control · 0.2near-infrared fluorescent markers · 0.2multispectral vision · 0.2
YearPublicationVenuePosition
2023 A Virtual Reality Planning Environment for High-Risk, High-Latency Teleoperation
abstract
Teleoperation of robots in space is challenging due to high latency and limited workspace visibility. Previously, the Interactive Planning and Supervised Execution (IPSE) and Augmented Virtuality systems were developed to reduce failure risk. These tools were visualized on a 3D da Vinci surgical console and operated using the da Vinci manipulators or visualized on conventional monitors and operated with a keyboard and mouse. Experimental studies indicated operator preference for the latter. In this work, we develop a 3D virtual reality (VR) interface for IPSE, implemented on a Meta Quest 2 head-mounted display (HMD), and evaluate it against the prior 2D, keyboard-and-mouse-based interface. The results demonstrate improved operator load with the 3D VR interface, with no decrease in task performance, while also providing cost and portability benefits compared to the conventional 2D interface.
Will Pryor, Liam J. Wang, Arko Chatterjee, Balázs Vágvölgyi, Anton Deguet, Simon Léonard, Louis L. Whitcomb, Peter Kazanzides
ICRA6
2021 Automated Mosquito Salivary Gland Extractor for PfSPZ-based Malaria Vaccine Production
abstract
Malaria is a worldwide scourge, and the broad deployment of an effective vaccine would improve the lives of millions of people. A vaccine based on Plasmodium falciparum (PfSPZ) sporozoites extracted from the salivary glands of infected mosquitoes shows significant promise. However, the large-scale industrial production of PfSPZ-based vaccines will benefit from automation of the key step of extracting sporozoites from mosquito salivary glands that is currently performed by manual microdissection. In this work, we demonstrate a robotic system prototype for extracting salivary glands from mosquitoes to streamline vaccine production and reduce the need for operators. In the proposed system, mosquitoes are decapitated in an automated robotic pick-place-decapitate process, then a squeezer apparatus extracts mosquito salivary glands from the body. Mosquito detection and body part localization are performed by computer vision methods. The software allows system operation in simulation and on the robotic hardware, which facilitates subsystem development and integration. Experiments show encouraging results with success rates of 93% in robotic mosquito manipulation and 87.1% in salivary gland extraction. The system has the potential to improve the efficiency of PfSPZ vaccine production with significant gains in throughput and reduction in training times for a highly deskilled initial manual step. Further, this system is expected to pave the way for a more mature future system.
Wanze Li, Zhuohong He, Parth Vora, Yanzhou Wang, Balázs Vágvölgyi, Simon Léonard, Anna Goodridge, Iulian Iordachita, Stephen L. Hoffman, Sumana Chakravarty, Russell H. Taylor
ICRA6
2020 Visual Monitoring and Servoing of a Cutting Blade during Telerobotic Satellite Servicing
abstract
We propose a system for visually monitoring and servoing the cutting of a multi-layer insulation (MLI) blanket that covers the envelope of satellites and spacecraft. The main contributions of this paper are: 1) to propose a model for relating visual features describing the engagement depth of the blade to the force exerted on the MLI blanket by the cutting tool, 2) a blade design and algorithm to reliably detect the engagement depth of the blade inside the MLI, and 3) a servoing mechanism to achieve the desired applied force by monitoring the engagement depth. We present results that validate these contributions by comparing forces estimated from visual feedback to measured forces at the blade. We also demonstrate the robustness of the blade design and vision processing under challenging conditions.
Amama Mahmood, Balázs Vágvölgyi, Will Pryor, Louis L. Whitcomb, Peter Kazanzides, Simon Léonard
IROS6
2020 Interactive Planning and Supervised Execution for High-Risk, High-Latency Teleoperation
abstract
Ground-based teleoperation of robot manipulators for on-orbit servicing of spacecraft represents an example of high-payoff, high-risk operations that are challenging to perform due to high latency communications, with telemetry time delays of several seconds. In these scenarios, confidence of operating without failure is paramount. We report the development of an Interactive Planning and Supervised Execution (IPSE) system that takes advantage of accurate 3D reconstruction of the remote environment to enable operators to plan motions in the virtual world, evaluate and adjust the plan, and then supervise execution with the ability to pause and return to the planning environment at any time. We report the results of an experimental evaluation of a representative on-orbit telerobotic servicing task from NASA's upcoming OSAM-1 mission to refuel a satellite in low earth orbit; specifically, to change the robot tool to acquire the fuel supply line and then to insert it into the satellite fill/drain valve. Results of a pilot study show that the operators preferred, and were more successful with, the IPSE system when compared to a conventional teleoperation implementation.
Will Pryor, Balázs Vágvölgyi, Anton Deguet, Simon Léonard, Louis L. Whitcomb, Peter Kazanzides
IROS4
2019 Experimental Evaluation of Teleoperation Interfaces for Cutting of Satellite Insulation
abstract
On-orbit servicing of satellites is complicated by the fact that almost all existing satellites were not designed to be serviced. This creates a number of challenges, one of which is to cut and partially remove the protective thermal blanketing that encases a satellite prior to performing the servicing operation. A human operator on Earth can perform this task telerobotically, but must overcome difficulties presented by the multi-second round-trip telemetry delay between the satellite and the operator and the limited, or even obstructed, views from the available cameras.This paper reports the results of ground-based experiments with trained NASA robot teleoperators to compare our recently-reported augmented virtuality visualization to the conventional camera-based visualization. We also compare the master console of a da Vinci surgical robot to the conventional teleoperation interface. The results show that, for the cutting task, the augmented virtuality visualization can improve operator performance compared to the conventional visualization, but that operators are more proficient with the conventional control interface than with the da Vinci master console.
Will Pryor, Balázs Vágvölgyi, William J. Gallagher, Anton Deguet, Simon Léonard, Louis L. Whitcomb, Peter Kazanzides
ICRA5
2019 Autonomous Laparoscopic Robotic Suturing with a Novel Actuated Suturing Tool and 3D Endoscope
abstract
Compared to open surgical techniques, laparoscopic surgical methods aim to reduce the collateral tissue damage and hence decrease the patient recovery time. However, constraints imposed by the laparoscopic surgery, i.e. the operation of surgical tools in limited spaces, turn simple surgical tasks such as suturing into time-consuming and inconsistent tasks for surgeons. In this paper, we develop an autonomous laparoscopic robotic suturing system. More specific, we expand our smart tissue anastomosis robot (STAR) by developing i) a new 3D imaging endoscope, ii) a novel actuated laparoscopic suturing tool, and iii) a suture planning strategy for the autonomous suturing. We experimentally test the accuracy and consistency of our developed system and compare it to sutures performed manually by surgeons. Our test results on suture pads indicate that STAR can reach 2.9 times better consistency in suture spacing compared to manual method and also eliminate suture repositioning and adjustments. Moreover, the consistency of suture bite sizes obtained by STAR matches with those obtained by manual suturing.
Hamed Saeidi, Hanh N. D. Le, Justin D. Opfermann, Simon Léonard, Michael H. Hsieh, Jin U. Kang, Axel Krieger
ICRA4
2019 Semi-autonomous Robotic Anastomoses of Vaginal Cuffs Using Marker Enhanced 3D Imaging and Path Planning
Michael Kam, Hamed Saeidi, Shuwen Wei, Justin D. Opfermann, Simon Léonard, Michael H. Hsieh, Jin U. Kang, Axel Krieger
MICCAI (5)5
2018 Semi-Autonomous Laparoscopic Robotic Electro-Surgery with a Novel 3D Endoscope * Research reported in this paper was supported by National Institute of Biomedical Imaging and Bioengineering of the National Institutes of Health under award numbers 1R01EB020610 and R21EB024707. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health
abstract
This paper reports a robotic laparoscopic surgery system performing electro-surgery on porcine cadaver kidney, and evaluates its accuracy in an open loop control scheme to conduct targeting and cutting tasks guided by a novel 3D endoscope. We describe the design and integration of the novel laparoscopic imaging system that is capable of reconstructing the surgical field using structured light. A targeting task is first performed to determine the average positioning error of the system as guided by the laparoscopic camera. The imaging system is then used to reconstruct the surface of a porcine cadaver kidney, and generate a cutting trajectory with consistent depth. The paper concludes by using the robotic system in open loop control to cut this trajectory using a multi degree of freedom electro-surgical tool. It is demonstrated that for a cutting depth of 3 mm, the robotic surgical system follows the trajectory with an average depth of 2.44 mm and standard deviation of 0.34 mm. The average positional accuracy of the system was 2.74±0.99 mm.
Hanh N. D. Le, Justin D. Opfermann, Michael Kam, Sudarshan Raghunathan, Hamed Saeidi, Simon Léonard, Jin U. Kang, Axel Krieger
ICRA6
2018 A Confidence-Based Shared Control Strategy for the Smart Tissue Autonomous Robot (STAR)
abstract
Autonomous robotic assisted surgery (RAS) systems aim to reduce human errors and improve patient outcomes leveraging robotic accuracy and repeatability during surgical procedures. However, full automation of RAS in complex surgical environments is still not feasible and collaboration with the surgeon is required for safe and effective use. In this work, we utilize our Smart Tissue Autonomous Robot (STAR) to develop and evaluate a shared control strategy for the collaboration of the robot with a human operator in surgical scenarios. We consider 2D pattern cutting tasks with partial blood occlusion of the cutting pattern using a robotic electrocautery tool. For this surgical task and RAS system, we i) develop a confidence-based shared control strategy, ii) assess the pattern tracking performances of manual and autonomous controls and identify the confidence models for human and robot as well as a confidence-based control allocation function, and iii) experimentally evaluate the accuracy of our proposed shared control strategy. In our experiments on porcine fat samples, by combining the best elements of autonomous robot controller with complementary skills of a human operator, our proposed control strategy improved the cutting accuracy by 6.4%, while reducing the operator work time to 44% compared to a pure manual control.
Hamed Saeidi, Justin D. Opfermann, Michael Kam, Sudarshan Raghunathan, Simon Léonard, Axel Krieger
IROS5
2018 Evaluation and Stability Analysis of Video-Based Navigation System for Functional Endoscopic Sinus Surgery on In Vivo Clinical Data
abstract
Functional endoscopic sinus surgery (FESS) is one of the most common outpatient surgical procedures performed in the head and neck region. It is used to treat chronic sinusitis, a disease characterized by inflammation in the nose and surrounding paranasal sinuses, affecting about 15% of the adult population. During FESS, the nasal cavity is visualized using an endoscope, and instruments are used to remove tissues that are often within a millimeter of critical anatomical structures, such as the optic nerve, carotid arteries, and nasolacrimal ducts. To maintain orientation and to minimize the risk of damage to these structures, surgeons use surgical navigation systems to visualize the 3-D position of their tools on patients' preoperative Computed Tomographies (CTs). This paper presents an image-based method for enhanced endoscopic navigation. The main contributions are: (1) a system that enables a surgeon to asynchronously register a sequence of endoscopic images to a CT scan with higher accuracy than other reported solutions using no additional hardware; (2) the ability to report the robustness of the registration; and (3) evaluation on in vivo human data. The system also enables the overlay of anatomical structures, visible, or occluded, on top of video images. The methods are validated on four different data sets using multiple evaluation metrics. First, for experiments on synthetic data, we observe a mean absolute position error of 0.21mm and a mean absolute orientation error of 2.8° compared with ground truth. Second, for phantom data, we observe a mean absolute position error of 0.97mm and a mean absolute orientation error of 3.6° compared with the same motion tracked by an electromagnetic tracker. Third, for cadaver data, we use fiducial landmarks and observe an average reprojection distance error of 0.82mm. Finally, for in vivo clinical data, we report an average ICP residual error of 0.88mm in areas that are not composed of erectile tissue and an average ICP residual error of 1.09mm in areas that are composed of erectile tissue.
Simon Léonard, Ayushi Sinha, Austin Reiter, Masaru Ishii, Gary L. Gallia, Russell H. Taylor, Gregory D. Hager
IEEE Trans. Medical Imaging1
2017 Semi-autonomous electrosurgery for tumor resection using a multi-degree of freedom electrosurgical tool and visual servoing
abstract
This paper specifies a surgical robot performing semi-autonomous electrosurgery for tumor resection and evaluates its accuracy using a visual servoing paradigm. We describe the design and integration of a novel, multi-degree of freedom electrosurgical tool for the smart tissue autonomous robot (STAR). Standardized line tests are executed to determine ideal cut parameters in three different types of porcine tissue. STAR is then programmed with the ideal cut setting for porcine tissue and compared against expert surgeons using open and laparoscopic techniques in a line cutting task. We conclude with a proof of concept demonstration using STAR to semi-autonomously resect pseudo-tumors in porcine tissue using visual servoing. When tasked to excise tumors with a consistent 4mm margin, STAR can semi-autonomously dissect tissue with an average margin of 3.67 mm and a standard deviation of 0.89mm.
Justin D. Opfermann, Simon Léonard, Ryan S. Decker, Nicholas A. Uebele, Christopher E. Bayne, Arjun S. Joshi, Axel Krieger
IROS2
2016 Plenoptic cameras in surgical robotics: Calibration, registration, and evaluation
abstract
Three-dimensional sensing of changing surgical scenes would improve the function of surgical robots. This paper explores the requirements and utility of a new type of depth sensor, the plenoptic camera, for surgical robots. We present a metric calibration procedure for the plenoptic camera and the registration of its coordinate frame to the robot (hand-eye calibration). We also demonstrate the utility in robotic needle insertion and application of sutures in phantoms. The metric calibration accuracy is reported as 1.14 ± 0.80 mm for the plenoptic camera and 1.57 ± 0.90 mm for hand-eye calibration. The accuracy of needle insertion task is 1.79 ± 0.35 mm for the entire robotic system. Additionally, the accuracy of suture placement with the presented system is reported at 1.80 ± 0.43 mm. Finally, we report consistent suture spacing with only 0.11 mm standard deviation between inter-suture distances. The measured accuracy of less than 2 mm with consistent suture spacing is a promising result to provide repeatable leak-free suturing with a robotic tool and a plenoptic depth imager.
Azad Shademan, Ryan S. Decker, Justin D. Opfermann, Simon Léonard, Peter C. W. Kim, Axel Krieger
ICRA4
2016 Anatomically Constrained Video-CT Registration via the V-IMLOP Algorithm
abstract
Functional endoscopic sinus surgery (FESS) is a surgical procedure used to treat acute cases of sinusitis and other sinus diseases. FESS is fast becoming the preferred choice of treatment due to its minimally invasive nature. However, due to the limited field of view of the endoscope, surgeons rely on navigation systems to guide them within the nasal cavity. State of the art navigation systems report registration accuracy of over 1mm, which is large compared to the size of the nasal airways. We present an anatomically constrained video-CT registration algorithm that incorporates multiple video features. Our algorithm is robust in the presence of outliers. We also test our algorithm on simulated and in-vivo data, and test its accuracy against degrading initializations. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
Seth Billings, Ayushi Sinha, Austin Reiter, Simon Léonard, Masaru Ishii, Gregory D. Hager, Russell H. Taylor
MICCAI (3)4
2015 Registration of planar virtual fixtures by using augmented reality with dynamic textures
abstract
This paper presents a method to align a virtual plane with a real plane in an augmented reality environment. The method addresses the challenge of configuring a planar virtual fixture during the teleoperation of a robot in a visually challenging environment. The method assists the operator to manually align the virtual plane with the real plane by providing visual cues by dynamically texturing the virtual plane. Following the manual initialization a robust evaluation of the optical flow is used to refine the alignment of the virtual plane. The system combines a stereo camera with a stereo display and generates visual distortions in the displayed images to indicate a misalignment of the virtual plane with the real one. The distortion is computed by displaying warped images from the left camera in the right display and vice versa. Results demonstrate that the method improves the accuracy of the alignment with a real plane that is covered with reflective multi-layer insulation.
Simon Léonard
ICRA1
2015 Experimental evaluation of force control for virtual-fixture-assisted teleoperation for on-orbit manipulation of satellite thermal blanket insulation
abstract
The ability to refuel satellites on-orbit using teleoperated robots could extend the life of satellite missions, potentially saving time and resources for both industry and space agencies. One critical step in the refueling process is to gain access to the satellite's fueling port by cutting through a seam of tape that adheres two sections of multi-layer insulation (MLI) covering the satellite body. The deformable, delicate, specular nature of the metalized tape used to adhere sections of MLI to one another makes cutting the tape seams a difficult task to perform remotely, a difficulty that is compounded by unavoidable multi-second communications delays. Virtual-fixture-assisted teleoperation can help mitigate some of these issues by constraining the motion of the cutting blade based on a priori knowledge of the task. Adding force control may further assist teleoperators by automatically setting a desired normal cutting force. This paper presents the results of a 20-participant user study for a representative satellite tape-cutting task, showing that force control based on a virtual fixture mapped to the MLI blanket plane can decrease both tape bunching and operator workload.
Steve Vozar, Simon Léonard, Peter Kazanzides, Louis L. Whitcomb
ICRA2
2014 Smart Tissue Anastomosis Robot (STAR): Accuracy evaluation for supervisory suturing using near-infrared fluorescent markers
abstract
This paper specifies and evaluates the accuracy of the Smart Tissue Anastomosis Robot (STAR). The STAR is a proof of concept vision-guided robotic system equipped with an actuated laparoscopic suturing tool and a multispectral vision system. The STAR supports image-based suturing commands and is capable of detecting near-infrared fluorescent (NIRF) markers that provide reliable visual segmentation and tracking. The paper reports the best case scenario accuracy specifications of the STAR as derived from its configuration and calibration parameters. We also evaluate experimentally the effects of overlaying NIRF markers on the accuracy of the STAR when these markers are used as the source of image-based commands and we compare these results to the accuracy of the STAR with image-based commands generated from plain color images. Our results demonstrate that the STAR is able to place sutures on a planar phantom with an average accuracy of 0.5 mm with a standard deviation of 0.2 mm and that NIRF markers have no statistically significant adverse effect on the accuracy.
Simon Léonard, Azad Shademan, Yonjae Kim, Axel Krieger, Peter C. W. Kim
ICRA1
2013 Model-based telerobotic control with virtual fixtures for satellite servicing tasks
abstract
Our goal is to develop new methods for telerobotic on-orbit servicing of spacecraft under ground-based supervisory control of human operators to perform tasks in the presence of uncertainty and telemetry time delay of several seconds. We propose a new delay tolerant control methodology, using virtual fixtures, hybrid position/force control, task frame formalism, and environment modeling, that is robust to modeling and registration errors. The task model is represented by graphical primitives and virtual fixtures on the teleoperation master and by a hybrid position/force controller on the slave robot. The virtual fixtures guide the operator through a model-based simulation of the task, and the goal of the slave controller is to reproduce this action (after a few seconds of delay) or, if measurements are not consistent with the models, to stop motion and alert the operator. This approach is suitable for tasks in unstructured environments, such as servicing of existing on-orbit spacecraft that were not designed for servicing. We introduce the overall control concept, its main components, and an example application in which the remote slave robot cuts the tape that secures a flap of multi-layer insulation over the access panel of a satellite mockup.
Simon Léonard, Isha Kandaswamy, Amy A. Blank, Louis L. Whitcomb, Peter Kazanzides
ICRA2
2012 Sequential scene parsing using range and intensity information
abstract
This paper describes an extension of the sequential scene analysis system presented by Hager and Wegbreit [12]. In contrast to the original system, which was limited to scenes consisting of geometric primitives, such as spheres, cuboids, and cylinders computed from range data, the extended system is capable of dealing with arbitrarily shaped objects computed from range and intensity images. An object model composed of a triangulated geometry and intensity-based SURF features is introduced. The integration of prior object models into the sequential scene parsing framework is described. The extended system is evaluated with respect to pose estimation and its ability to handle complex scene sequences. It is shown that the new object models enable accurate pose estimation and reliable recognition even in highly cluttered scenes.
Manuel Brucker, Simon Léonard, Tim Bodenmüller, Gregory D. Hager
ICRA2
2012 Augmented reality environment with virtual fixtures for robotic telemanipulation in space
abstract
This paper presents an augmented reality framework, implemented on the master console of a modified da Vinci® surgical robot, that enables the operator to design and implement assistive virtual fixtures during teleoperation. Our specific goal is to facilitate teleoperation with large time delays, such as the delay of several seconds that occurs with ground-based control of robotic systems in earth orbit. The virtual fixtures give immediate visual feedback and motion guidance to the operator, while the remote slave performs motions consistent with those constraints. This approach is suitable for tasks in unstructured environments, such as servicing of existing on-orbit spacecraft that were not designed for servicing. We conducted a pilot study by teleoperating a remote slave robot for a thermal barrier blanket cutting task using virtual fixtures with and without time delay. The results show that virtual fixtures reduce the time required to complete the task while also eliminating significant manipulation errors, such as tearing the blanket. The improvement in performance is especially dramatic when a simulated time delay (4 seconds) is introduced.
Simon Léonard, Anton Deguet, Louis L. Whitcomb, Peter Kazanzides
IROS2
2010 Path Planning for Improved Visibility Using a Probabilistic Road Map
abstract
This paper focuses on the challenges of vision-based motion planning for industrial manipulators. Our approach is aimed at planning paths that are within the sensing and actuation limits of industrial hardware and software. Building on recent advances in path planning, our planner augments probabilistic road maps with vision-based constraints. The resulting planner finds collision-free paths that simultaneously avoid occlusions of an image target and keep the target within the field of view of the camera. The planner can be applied to eye-in-hand visual-target-tracking tasks for manipulators that use point-to-point commands with interpolated joint motion.
Matthew A. Baumann, Simon Léonard, Elizabeth A. Croft, James J. Little
IEEE Trans. Robotics2
2009 Planning collision-free and occlusion-free paths for industrial manipulators with eye-to-hand configuration
abstract
This paper presents a motion planning algorithm for industrial manipulators with the simultaneous constraints of avoiding collisions and avoiding the occlusion of specified pixellated regions of an eye-to-hand camera. The system uses a probabilistic roadmap to satisfy the constraints imposed by the command interface of typical industrial manipulators and uses dynamic collision checking to ensure collision-free motion. In the context of a task monitored by a camera, we enhance a probabilistic roadmap with a dynamic occlusion checking algorithm that is able to determine which pixels of the camera are occluded by the robot during each motion segment. The occlusion algorithm is formulated as collision algorithm where the field of view of the camera is represented as a quadtree of frustums. The proposed algorithm is demonstrated in industrial bin picking simulations where the gripper must not occlude the targeted object throughout the task.
Simon Léonard, Elizabeth A. Croft, James J. Little
IROS1
2008 Dynamic visibility checking for vision-based motion planning
abstract
An important problem in position-based visual servoing (PBVS) is to guarantee that a target will remain within the field of view for the duration of the task. In this paper, we propose a dynamic visibility checking algorithm that, given a parametrized trajectory of the camera, determines if an arbitrary 3D target will remain within the field of view. We reformulate this problem as the problem of determining if the 3D coordinates of the target collide with the frustum formed by the camera field of view during the camera trajectory. To solve this problem, our algorithm computes and compares the shortest distance between the target and the frustum with the length of the trajectory described by the target in the camera's coordinate frame. Furthermore, we demonstrate that our algorithm can be combined with path planning algorithms and, in particular, probabilistic roadmaps (PRM). Results suggest that our algorithm is computationally efficient even when the target moves in the vicinity of image borders. In simulations, we use our dynamic visibility checking algorithm in conjunction with a PRM to plan collision free paths while providing the guarantee that a specific target will not leave the field of view.
Simon Léonard, Elizabeth A. Croft, James J. Little
ICRA1
2008 Occlusion-free path planning with a probabilistic roadmap
abstract
We present a novel algorithm for path planning that avoids occlusions of a visual target for an ldquoeye-in-handrdquo sensor on an articulated robot arm. We compute paths using a probabilistic roadmap to avoid collisions between the robot and obstacles, while penalizing trajectories that do not maintain line-of-sight. The system determines the space from which line-of-sight is unimpeded to the target (the visible region). We assign penalties to trajectories within the roadmap proportional to the distance the camera travels while outside the visible region. Using Dijkstrapsilas algorithm, we compute paths of minimal occlusion (maximal visibility) through the roadmap. In our experiments, we compare a shortest-distance path to the minimal-occlusion path and discuss the impact of the improved visibility.
Matthew A. Baumann, Donna C. Dupuis, Simon Léonard, Elizabeth A. Croft, James J. Little
IROS3
2007 On with the Visuomotor Function: A 6DOF Adaptive Approach for Modeling Image-Based Variations and Visual Servoing
abstract
In this paper, we proposes a visual servoing method that approximates the relation between the variations of image points and the variations of a stereo rig in Euclidian space. As with most image-based visual servoing methods, commands are expressed in the space of image features. However, instead of relating instantaneous image-based variations to instantaneous variations in Euclidian space, the visuomotor function relates arbitrary image-based variations to Euclidian transformations. The visuomotor function is approximated in real-time by using online estimation techniques. The system improves its performance with experience and is able to adapt to different configurations of the cameras or environment. Given the disparities between two sets of corresponding image points, the visuomotor function provides the Euclidian transformation the robot must execute in order to align the image coordinates.
Simon Léonard, Martin Jägersand
ICRA1
2006 Adaptive Control for Estimating Translations from Image-based Variations
abstract
We investigate the problem of learning the mapping between arbitrary image-based variations and variations in Euclidean space for the application of visual-servoing. We derive a linear formulation of the visuomotor function, which captures this relationship for three dimensional translations. The resulting expression defines how the origin of the world coordinate frame shifts in stereo images as the robot translates. The parameters of the visuomotor function are estimated online by using incremental least squares and are generalized to other coordinate frames origins by using a function approximation method. It follows that the system is able to estimate the three dimensional translations between pairs of stereo points without performing 3D reconstruction or requiring a specific coordinate system and is fully adaptive
Simon Léonard, Martin Jägersand
ICRA1
2005 Incremental Learning for Mapping Image Variations to Actions
abstract
In this paper we introduce a method to learn the global relationship between camera motion and its effect on a feature space. Drawing from progress in vision based motion control, we derive an image-based method that learns an approximation of the visuomotor function while performing visual servoing tasks. The result is a reactive agent that measures its performance in the image feature space and controls a robot with position error commands. Thus combining image-based references with position-based commands.
Simon Léonard, Martin Jägersand
ICRA1
2004 Learning based visual servoing
abstract
This paper proposes a method for learning a hand-eye calibration and its application for visual servoing. The goal is to develop a technique that combines the strengths of existing visual servoing methods. Particularly, as in image-based visual servoing, the error is measured in the visual space while the motor command is position-based. Hence this method approximates the visuomotor function that relates variations in the visual space to variations in the motor space at a global scale. The method used for approximating the visuomotor function is derived from the field of reinforcement learning, making our hand-eye calibration autonomous, continuous and adaptable. The visuomotor function is modeled by a linear combination of polynomials, each spanning a non-mutually exclusive subset of the visual space. Each polynomial represents the utility of motor commands for the servoing task. The goal of the calibration is to approximate the parameters of these polynomials while the system interacts with its environment. Preliminary results include centering a target in the image in which the system learns the motor commands that eliminates the errors in the visual space and generalizes the result to neighboring states in the visual space, depths and motor commands.
Simon Léonard, Martin Jägersand
IROS1
1999 Associative memory for geon-based object identification
abstract
Online inspection for defects in manufactured parts is a challenging problem and a crucial issue for any production process. Precise and extended CAD data describe the manufactured part under inspection and can be stored in a database in order to perform comparisons between the measured observed part (with a 3D laser camera, for instance) and its CAD description. The problem is very slow access time to find the right CAD model, because of the huge amount of data necessary to represent even a very simple manufactured piece. We propose a fast access to the database based on a vision-derived representation of the part, much less precise than the CAD representation but which offers a very low storage requirement. CAD representations of the models are converted off-line into a vision-based representation used to train a neural network. Volumetric projected components (geons) and their interrelationship are extracted from the digitized image of the piece under inspection and input to a neural network whose outputs point to the most probable models in the large database. Corresponding CAD data is then available for the inspection module.
Simon Léonard, Richard Lepage, Tanneguy Redarce
IJCNN1